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  • 1.
    Abada, Maria
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Fossum, Elin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Brandt, Louise
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Åkesson, Anton
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Property prediction of super-strong nanocellulose fibers2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The innovative technology behind production of strong biofilaments involves the process of spinning filaments from nanoparticles extracted from wood. These nanoparticles are called cellulose nanofibrils (CNFs). The spun filaments can have high mechanical properties, rivaling many other plant based materials, and could be an environmentally friendly replacement for many materials in the future such as fabrics and composites. Before mass production might be possible, the optimal dispersion properties must be determined for the intended use, with regard to concentration, method of oxidation (TEMPO-oxidation or carboxymethylation) and pretreatment through sonication and centrifugation.

    In this bachelor’s thesis attributes of spun filaments were investigated in order to find a correlation between mechanical properties and the effects of concentration, method of oxidation as well as sonication and centrifugation of the dispersions. The mechanical properties were also compared to the fibrils’ ability to entangle and align during flow-focusing. A variety of analytical methods: flow-stop, tensile testing, scanning electron microscopy (SEM) and wide angle X-ray scattering (WAXS) were implemented for the dispersions and filaments.

    The results from this study show that flow-stop analysis could be used to determine which CNF dispersions are spinnable and which are non-spinnable, along with which spinnable dispersion would yield the strongest filament. It was also concluded that crystallinity of fibrils affects the mechanical properties of filaments and that TCNFs are generally more crystalline than CMCs. Pretreatment through sonication and centrifugation seems to have a negative impact on spinnability and sonication in combination with low concentration seems to lead to non-spinnable conditions. On the other hand, sonicated dispersions seem to yield a greater number of samples without aggregates than non-sonicated ones. Aggregates, however, seem to only affect ultimate stress out of the measured mechanical properties. Furthermore, concentration and viscosity affect spinnability and CMC dispersions seem to yield thicker filaments than TCNF dispersions. However, due to lack of statistically validated data any definitive conclusions could not be drawn.

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  • 2.
    Abbasi Aval, Negar
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology. Isfahan Univ Technol, Dept Mat Engn, Biomat Res Grp, Esfahan 8475683777, Iran.;Isfahan Univ Med Sci, Sch Med, Dept Anat Sci, Esfahan, Iran..
    Emadi, Rahmatollah
    Isfahan Univ Technol, Dept Mat Engn, Biomat Res Grp, Esfahan 8475683777, Iran..
    Valiani, Ali
    Isfahan Univ Med Sci, Sch Med, Dept Anat Sci, Esfahan, Iran..
    Kharaziha, Mahshid
    Isfahan Univ Technol, Dept Mat Engn, Biomat Res Grp, Esfahan 8475683777, Iran..
    Finne Wistrand, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    An aligned fibrous and thermosensitive hyaluronic acid-puramatrix interpenetrating polymer network hydrogel with mechanical properties adjusted for neural tissue2022In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 57, no 4, p. 2883-2896Article in journal (Refereed)
    Abstract [en]

    Central nervous system (CNS) injuries such as stroke or trauma can lead to long-lasting disability, and there is no currently accepted treatment to regenerate functional CNS tissue after injury. Hydrogels can mimic the neural extracellular matrix by providing a suitable 3D structure and mechanical properties and have shown great promise in CNS tissue regeneration. Here we present successful synthesis of a thermosensitive hyaluronic acid-RADA 16 (Puramatrix (TM)) peptide interpenetrating network (IPN) that can be applied in situ by injection. Thermosensitive hyaluronic acid (HA) was first synthesized by combining HA with poly(N-isopropylacrylamide). Then, the Puramatrix (TM) self-assembled peptide was combined with the thermosensitive HA to produce a series of injectable thermoresponsive IPNs. The HA-Puramatrix (TM) IPNs formed hydrogels successfully at physiological temperature. Characterization by SEM, rheological measurements, enzymatic degradation and swelling tests was performed to select the IPN optimized for neurologic use. SEM images of the optimized dry IPNs demonstrated an aligned porous structure, and the rheological measurements showed that the hydrogels were elastic, with an elastic modulus of approximately 500 Pa, similar to that of brain tissue. An evaluation of the cell-material interactions also showed that the IPN had biological characteristics required for tissue engineering, strongly suggesting that the IPN hydrogel possessed properties beneficial for regeneration of brain tissue.

  • 3. Abitbol, T.
    et al.
    Ahniyaz, A.
    Álvarez-Asencio, R.
    Fall, A.
    Swerin, Agne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Nanocellulose-Based Hybrid Materials for UV Blocking and Mechanically Robust Barriers2020In: ACS Applied Bio Materials, E-ISSN 2576-6422, Vol. 3, no 4, p. 2245-2254Article in journal (Refereed)
    Abstract [en]

    Nanocellulose (NC)-based hybrid coatings and films containing CeO2 and SiO2 nanoparticles (NPs) to impart UV screening and hardness properties, respectively, were prepared by solvent casting. The NC film-forming component (75 wt % of the overall solids) was composed entirely of cellulose nanocrystals (CNCs) or of CNCs combined with cellulose nanofibrils (CNFs). Zeta potential measurements indicated that the four NP types (CNC, CNF, CeO2, and SiO2) were stably dispersed in water and negatively charged at pH values between 6 and 9. The combination of NPs within this pH range ensured uniform formulations and homogeneous coatings and films, which blocked UV light, the extent of which depended on film thickness and CeO2 NP content, while maintaining good transparency in the visible spectrum (∼80%). The addition of a low amount of CNFs (1%) reduced the film hardness, but this effect was compensated by the addition of SiO2 NPs. Chiral nematic self-assembly was observed in the mixed NC film; however, this ordering was disrupted by the addition of the oxide NPs. The roughness of the hybrid coatings was reduced by the inclusion of oxide NPs into the NC matrix perhaps because the spherical oxide NPs were able to pack into the spaces between cellulose fibrils. We envision these hybrid coatings and films in barrier applications, photovoltaics, cosmetic formulations, such as sunscreens, and for the care and maintenance of wood and glass surfaces, or other surfaces that require a smooth, hard, and transparent finish and protection from UV damage.

  • 4. Adamus, Grazyna
    et al.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kowalczuk, Marek
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    MALDI-TOF MS Reveals the Molecular Level Structures of Different Hydrophilic-Hydrophobic Polyether-esters2009In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, no 6, p. 1540-1546Article in journal (Refereed)
    Abstract [en]

    Multi- and triblock copolymers based on 1,5-dioxepan-2-one/epsilon-caprolactone (DXO/CL) were investigated by MALDI-TOF MS to determine the influence of copolymer composition and architecture on the molecular structures at the individual chain level. The copolymer compositions, average block lengths, and molecular weights were determined by H-1 and C-13 NMR and by SEC, respectively. The structures of polyether-ester oligomers (linear, cyclic) as well as the chemical structures of their end groups were established on the basis of their MALDI-TOF mass spectra. The mass spectrum of PDXO homopolymer was relatively simple, however, complex mass spectra were obtained in the case of multi- and triblock copolymers and the mass spectra clearly discerned the molecular level effect of copolymer composition and copolymer type.

  • 5. Adekunle, Kayode
    et al.
    Cho, Sung-Woo
    Patzelt, Christian
    Blomfeldt, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Skrifvars, Mikael
    Impact and flexural properties of flax fabrics and Lyocell fiber-reinforced bio-based thermoset2011In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 30, no 8, p. 685-697Article in journal (Refereed)
    Abstract [en]

    A bio-based thermoset resin was reinforced with flax fabrics and Lyocell fiber. The effect of different weave architectures was studied with four flax fabrics with different architectures: plain, twill (two different types), and dobby. The effect of the outer ply thickness was studied and characterized with flexural and impact testing. Composites manufactured with plain weave reinforcement had the best mechanical properties. The tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength were 280MPa, 32GPa, 250MPa, 25GPa, and 75 kJ/m (2), respectively. Reinforcements with twill-weave architecture did not impart appreciable flexural strength or flexural modulus even when the outer thickness was increased. Plain- and dobby (basket woven style)-weave architectures gave better reinforcing effects and the flexural properties increased with an increase in outer thickness. Water absorption properties of the composites were studied and it was observed that the hybridization with Lyocell fiber reduced the water uptake. Field-emission scanning electron microscopy was used to study the micro-structural properties of the composites.

  • 6.
    Afewerki, Samson
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Combined Catalysis: A Powerful Strategy for Engineering Multifunctional Sustainable Lignin-Based Materials2023In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 17, no 8, p. 7093-7108Article in journal (Refereed)
    Abstract [en]

    The production and engineering of sustainable materials through green chemistry will have a major role in our mission of transitioning to a more sustainable society. Here, combined catalysis, which is the integration of two or more catalytic cycles or activation modes, provides innovative chemical reactions and material properties efficiently, whereas the single catalytic cycle or activation mode alone fails in promoting a successful reaction. Polyphenolic lignin with its distinctive structural functions acts as an important template to create materials with versatile properties, such as being tough, antimicrobial, self-healing, adhesive, and environmentally adaptable. Sustainable lignin-based materials are generated by merging the catalytic cycle of the quinone-catechol redox reaction with free radical polymerization or oxidative decarboxylation reaction, which explores a wide range of metallic nanoparticles and metal ions as the catalysts. In this review, we present the recent work on engineering lignin-based multifunctional materials devised through combined catalysis. Despite the fruitful employment of this concept to material design and the fact that engineering has provided multifaceted materials able to solve a broad spectrum of challenges, we envision further exploration and expansion of this important concept in material science beyond the catalytic processes mentioned above. This could be accomplished by taking inspiration from organic synthesis where this concept has been successfully developed and implemented.

  • 7.
    Ahlinder, Astrid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Charlon, Sebastien
    IMT Lille Douai, Ecole nationale supérieure Mines-Télécom Lille Douai, Materials & Processes Center, Cité scientifique, Villeneuve d'Ascq Cedex, France.
    Fuoco, Tiziana
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Soulestin, Jeremie
    IMT Lille Douai, Ecole nationale supérieure Mines-Télécom Lille Douai, Materials & Processes Center, Cité scientifique, Villeneuve d'Ascq Cedex, France.
    Finne Wistrand, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Minimise thermo-mechanical batch variations when processing medical grade lactide based copolymers in additive manufacturing2020In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 181, article id 109372Article in journal (Refereed)
    Abstract [en]

    Additive manufacturing is suitable for producing complex geometries; however, variation in thermo-mechanical properties are observed during one batch cycle when degradable aliphatic polyesters of medical grade are used in melt extrusion-based methods. This is one important reason for why additive manufacturing has not yet been fully utilised to produce degradable medical implants. Herein, the internal variation has been minimised during one batch cycle by assessing the effect of different processing parameters when using commercially available medical grade copolymers. To minimise the molar mass, thermal and mechanical variation within one batch cycle, the rheological fingerprint of the commercially available medical grade poly(L-lactide-co-ε-caprolactone) and poly(L-lactide-co-trimethylene carbonate) has been correlated to the process parameters of the ARBURG Plastic Freeforming. An increase in the temperature up to 220°C and the associated increase in pressure are beneficial for the viscoelastic and thermally stable poly(L-lactide-co-ε-caprolactone). In contrast, a temperature below 220°C should be used for the poly(L-lactide-co-trimethylene carbonate) to reduce the variation in strain at break during one batch cycle. The residence time is decreased through the increase of the discharge parameter. An increase in temperature is however required to reduce the viscosity of the polymer and allow the pressure to stay within the machine limitations at higher discharge parameters. The results are highly relevant to the development of additive manufacturing for the production of degradable medical devices with identical properties. In fact, Food and Drug Administration guidelines for additive manufacturing of medical implants specify the need to control changes in material properties during the process.

  • 8.
    Ahlinder, Astrid
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Fuoco, Tiziana
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Finne Wistrand, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Medical grade polylactide, copolyesters and polydioxanone: Rheological properties and melt stability2018In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 72, p. 214-222Article in journal (Refereed)
    Abstract [en]

    Rheological measurements have shown that lactide-based copolymers with L-lactide content between 50 and 100 mol% with varying comonomers, as well as polydioxanone (PDX), can be used in additive manufacturing analogously to poly(L-lactide) (PLLA) if their melt behaviour are balanced. The results indicate that copolymers can be melt processed if the temperature is adjusted according to the melting point, and parameters such as the speed are tuned to conteract the elastic response. Small amplitude oscillatory shear (SAOS) rheology, thermal and chemical characterisation allowed us to map the combined effect of temperature and frequency on the behaviour of six degradable polymers and their melt stability. Values of complex viscosity and Tan delta obtained through nine time sweeps by varying temperature and frequency showed that the molecular structure and the number of methylene units influenced the results, copolymers of L-lactide with D-Lactide (PDLLA) or glycolide (PLGA) had an increased elastic response, while copolymers with trimethylene carbonate (PLATMC) or epsilon-caprolactone (PCLA) had a more viscous behaviour than PLLA, with respect to their relative melting points. PDLLA and PLGA require an increased temperature or lower speed when processed, while PLATMC and PCLA can be used at a lower temperature and/or higher speed than PLLA. PDX showed an increased viscosity compared to PLLA but a similar melt behaviour. Negligible chain degradation were observed, apart from PLGA.

  • 9.
    Ahlström, Leon
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Mattsson, Rebecca
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Eurén, Hampus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Lidén, Alicia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Spruce bark biorefinery2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Spruce Bark contains several fundamental main substances; lignin, non-cellulose polysaccharides, cellulose and extractives. This undergraduate study focuses on developing a process to extract each of these components from spruce bark using a biorefinery concept, with a main focus on extracting lignin without degradation. The purpose of the Bark biorefinery concept is to contribute to a circular bioeconomy, by making use of natural resources. With extended research on the area, it will be possible to produce polymers, green chemicals and biofuel from the components in bark. 

    This report covers the extraction of the bark components with soxhlet extraction, Hot-water extraction, organosolv extraction and peracetic acid delignification. The extraction was made on two samples, matchstick-sized bark (MS) and 20 mesh-sized bark with a diameter of 0.8 mm (20M). The purpose was to be able to compare the efficiency of the extraction between the two samples. Afterwards, the characterisation of extracts and residue was executed with carbohydrate analysis, 2D HSQC-NMR and FTIR-analysis. 

    The results showed that a smaller particle size led to more efficient extractions of all components as well as more pure extract solutions. Lignin concentration determinations of samples at each step showed that a significant amount of lignin was lost prior to the organosolv extraction. Future research should look into ways to reduce this loss in order to increase the lignin yield. The findings in the FTIR and NMR analyses correlates with what could be seen in other reports, discussing similar subjects. For upscaling of this process, future research should go toward optimization of all extraction methods in order to make an upscaling of the process economically viable.  

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  • 10.
    Akhlaghi, Shahin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Brana, M. T. Conde
    Bellander, M.
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Deterioration of acrylonitrile butadiene rubber in rapeseed biodiesel2015In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 111, p. 211-222Article in journal (Refereed)
    Abstract [en]

    The deterioration of acrylonitrile butadiene rubber (NBR) exposed to rapeseed biodiesel at 90 degrees C was studied. The oxidation of biodiesel and NBR during ageing was monitored by H-1 NMR and infrared spectroscopy, HPLC and titration methods. The oxidation of biodiesel was impeded in the presence of NBR, but promoted in biodiesel-exposed rubber. This was explained as being due to the migration of stabilizer from the rubber to biodiesel, the diffusion of dissolved oxygen from biodiesel into NBR and the absorption of oxidation precursors of biodiesel by the rubber. The resemblance between the anomalous sorption kinetics of biodiesel in NBR and the equilibrium benzene uptake by the aged rubbers revealed that biodiesel caused a network defect in NBR, resulting in a gradual increase in the equilibrium swelling. The cleavage of crosslinks was implausible since the Young's modulus of the rubber at low strains, disregarding an initial decrease, increased with increasing exposure time. The appearance of 'naked' carbon black particles in the scanning electron micrographs of the aged rubbers and a drastic decrease in the strain-at-break of NBR after exposure to biodiesel suggests that internal cavitation was caused by the attack of biodiesel on the acrylonitrile units of NBR.

  • 11.
    Akhlaghi, Shahin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Pourrahimi, Amir Masoud
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hedenqvist, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Sjöstedt, C.
    Bellander, M.
    Gedde, Ulf
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Degradation of carbon-black-filled acrylonitrile butadiene rubber in alternative fuels: Transesterified and hydrotreated vegetable oils2016In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 123, p. 69-79Article in journal (Refereed)
    Abstract [en]

    The deterioration of acrylonitrile butadiene rubber (NBR), a common sealing material in automobile fuel systems, when exposed to rapeseed biodiesel and hydrotreated vegetable oil (HVO) was studied. The fuel sorption was hindered in HVO-exposed rubber by the steric constraints of bulky HVO molecules, but it was promoted in biodiesel-exposed rubber by fuel-driven cavitation in the NBR and by the increase in diffusivity of biodiesel after oxidation. The absence of a tan δ peak of the bound rubber and the appearance of carbon black particles devoid of rubber suggested that the cavitation was made possible in biodiesel-aged rubber by the detachment of bound rubber from particle surfaces. The HVO-exposed NBR showed a small decrease in strain-at-break due to the migration of plasticizer from the rubber, and a small increase in the Young’s modulus due to oxidative crosslinking. A drastic decrease in extensibility and Payne-effect amplitude of NBR on exposure to biodiesel was explained as being due to the damage caused by biodiesel to the continuous network of bound rubber-carbon black. A decrease in the ZnO crystal size with increasing exposure time suggested that the particles are gradually dissolved in the acidic components of oxidized biodiesel. The Zn2+ cations released from the dissolution of ZnO particles in biodiesel promoted the hydrolysis of the nitrile groups of NBR.

  • 12.
    Albertsson, Ann-Christine
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Celebrating 20 years of Biomacromolecules!2019In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, no 2, p. 767-768Article in journal (Refereed)
  • 13.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Long-Term Properties of Polyolefins2004Collection (editor) (Refereed)
    Abstract [en]

    We dedicate the current volume entitled "Long-Term Properties of Polyolefins"to Professor Kausch on his 25th anniversary as editor of Advances in PolymerScience. Professor Kausch pioneered the work on molecular effects in thefracture of polymers. This is beautifully summarized in his books on polymerfracture. Professor Kausch is also the perfect gentleman - always eager to helpnewcomers to make their entrance into the scientific community and to assisthis colleagues in their work and accomplishments. With his work, ProfessorKausch has demonstrated the importance of "source science" - to present newdata - and to present reviews of previously published material. This book ispresented in the spirit of Professor Kausch, namely showing a good selection ofdata and explaining what they mean.The main focus of this book is the relation between structure and propertiesand the trend towards better quality and reproducibility. The first chapterdescribes the metallocene polymerisation catalysts and their possihility notonly of tailoring polymer properties but also of manufacturing entirely newmaterials. Due to improved control of microstructure, it will also be possible toproduce specialty polyolefins which could compete with non-olefinic polymers.The next chapter shows how in each new development step catalyst and processinnovations have gone hand in hand and how the control over polymer structureand the ability to tailor material properties has increased. For a betterunderstanding of properties and behaviour, the basic of morphology is fundamentaland is described in chapter three, followed by chapter four aboutfracture properties and microdeformation behaviour. Promising model systemsfor the investigations of the relations between crack-tip deformation, fractureand molecular structure are also presented. Chapter five gives an overviewof stabilization of polyethylene crucial for long-term properties. Two mainapproaches have been used; the first advocates the use of biological antioxidants,and the second relies on the use of reactive antioxidants that are chemicallyattached onto the polymer backbone for greater performance and safety.Chemiluminescence is presented as a too1 for studying the initial stages inoxidative degradation and is explained in chapter six. However, for many years,tailor-made structures specially designed for environmental degradation havealso been a reality. One of the key questions for successhl development and useof environmentally degradable polymers is the interaction between the degradationprodncts and nature and this is illustrated in chapter seven. The developmentof chromatographic methods and use of chromatographic fingerprintinggives not only degradation products bnt also information about degradationmechanisms as well as interaction between the polymer and different environments.The obstacles and possibilities for recycling of polyolefins are discussedin chapter eigbt with special emphasis on analytical methods useful in theqnality concept. It is also shown how recycled material could be a valuable resourcein the Future together with renewable resources. Finally, chapter ninegives examples of existing as we11 as emerging techniques of surface modificationof polyethylene.These chapters together will hopefuiiy inspire to a new generation of polyethyleneby mimicking nature and use of new molecular architecture, newmorphology and also "activated" additives in microdomains, with even morereproducible properties within oarrow limits and with predetermined lifetimes.

  • 14.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    New matrices for controlled drug delivery.2000In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, American Chemical Society (ACS), 2000Conference paper (Refereed)
  • 15.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Novel release systems from biodegradable polymers1998In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, American Chemical Society (ACS), 1998Conference paper (Refereed)
  • 16.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Källrot, Martina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Surface modification of degradable polymers2005In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, American Chemical Society (ACS), 2005Conference paper (Refereed)
  • 17.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Varma, Indra Kumari
    Centre for Polymer Science and Engineering, Indian Institute of Technology, Dehli, India.
    Synthesis, Chemistry and Properties of Hemicelluloses2011In: Biopolymers: New Materials for Sustainable Films and Coatings / [ed] David Plackett, Chichester: John Wiley & Sons, 2011, 1, p. 135-150Chapter in book (Other academic)
  • 18.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Degradable polymers with tailored properties for biomedical materials2009In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 238Article in journal (Other academic)
  • 19.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Groning, M.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Emission of volatiles from polymers - A new approach for understanding polymer degradation2006In: Journal of Polymers and the Environment, ISSN 1566-2543, E-ISSN 1572-8919, Vol. 14, no 1, p. 8-13Article in journal (Refereed)
    Abstract [en]

    Emission of low molar mass compounds from different polymeric materials was determined and the results from the volatile analysis were applied to predict the degree of degradation and long-term properties, to determine degradation rates and mechanisms, to differentiate between biotic and abiotic degradation and for quality control work. Solid-phase microextraction and solid-phase extraction together with GC-MS were applied to identify and quantify the low molar mass compounds. Volatiles were released and monitored at early stages of degradation before any matrix changes were observed by e.g. SEC, DSC and tensile testing. The analysis of volatiles can thus also be applied to detect small differences between polymeric materials and their susceptibility to degradation. The formation of certain degradation products correlated with the changes taking place in the polymer matrix, these indicator products could, thus, be analysed to rapidly predict the degree of degradation in the polymer matrix and further to predict the long-term properties and remaining lifetime of the product.

  • 20.
    Albertsson, Ann-Christine
    et al.
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    The influence of biotic and abiotic environments on the degradation of polyethylene1990In: Progress in polymer science, ISSN 0079-6700, E-ISSN 1873-1619, Vol. 15, no 2, p. 177-192Article in journal (Refereed)
  • 21.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Kumari Varma, Indra
    Centre for Polymer Science and Engineering, Indian Institute of Technology, New Dehli, India.
    Srivastava, Rajiv K.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Polyesters from Large Lactones2009In: Handbook of Ring-Opening Polymerization / [ed] Philippe Dubois, Olivier Coulembier, Jean-Marie Raquez, Wiley-VCH Verlagsgesellschaft, 2009, 1, p. 287-306Chapter in book (Other academic)
  • 22.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Källrot, Martina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    POLY 585-Covalent surface modification of degradable polymers2007In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 234Article in journal (Other academic)
  • 23.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Controlled synthesis of star-shaped homo- and co-polymers of aliphatic polyesters2006In: 7th International Biorelated Polymers Symposium, 2006, p. 37-38Conference paper (Refereed)
    Abstract [en]

    The challenges in finding a material with the proper characteristics for a given tissue engineering application are several. One solution is improving the ability to tailor the mechanical and physical properties along with the degradation profile of aliphatic polyesters, by for example alterations in their composition and architecture. In this study, well-defined star-shaped aliphatic polyesters constituted of four arms were synthesized. As a model system, L,L-lactide and a spirocyclic tin initiator was chosen and the affect of the solvent, temperature and monomer-to-initiator ratio on the number average molecular weight, the molecular weight distribution and the conversion of the polymers was shown. Consecutively, we proved that well-defined star-shaped block copolymers composed of 1,5-dioxepan-2-one and L,L-lactide with narrow molecular weight distributions and controlled block lengths can be synthesized using this system.

  • 24.
    Albertsson, Ann-Christine
    et al.
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Olander, Björn
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Edlund, Ulrica
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Källrot, Martina
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Increased biocompatibility by surface modification2004In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 228, p. U508-U508Article in journal (Other (popular science, discussion, etc.))
  • 25.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Percec, Simona
    Future of Biomacromolecules at a Crossroads of Polymer Science and Biology2020In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 21, no 1, p. 1-6Article in journal (Refereed)
  • 26.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Varma, Indra Kumari
    Centre for Polymer Science and Engineering, Indian Institute of Technology, Dehli, India.
    Lochab, Bimlesh
    Centre for Polymer Science and Engineering, Indian Institute of Technology, Dehli, India.
    Finne Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Kumar, Kamlesh
    Centre for Polymer Science and Engineering, Indian Institute of Technology, Dehli, India.
    Design and Syntesis of Different Types of Poly(Lactic acid)2010In: Poly(Lactic Acid): Synthesis, Structures, Properties, Processing and Applications / [ed] Rafael Auras, Loong-Tak Lim, Susan E. M. Selke, Hideto Tsuji, John Wiley & Sons, 2010, p. 43-58Chapter in book (Other academic)
  • 27.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Varma, Indra Kumari
    Centre for Polymer Science and Engineering, Indian Institute of Technology, New Delhi, India.
    Lochab, Bimlesh
    Materials Research Laboratory, Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Greater Noida, India.
    Finne Wistrand, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sahu, Sangeeta
    Materials Research Laboratory, Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Tehsil Dadri, India.
    Kumar, Kamlesh
    Council of Scientific and Industrial Research, Central Scientific Instruments Organization, Chandigarh, India.
    Design and synthesis of different types of poly(lactic acid)/polylactide copolymers2022In: Poly(lactic acid): Synthesis, Structures, Properties, Processing, Applications, and End of Life, Wiley , 2022, p. 45-71Chapter in book (Other academic)
    Abstract [en]

    High molar mass poly(lactic acid) (PLA) is obtained by either the polycondensation of lactic acid or ring-opening polymerization (ROP) of the cyclic dimer 2,6-dimethyl-1,4-dioxane-2,5-dione, commonly referred to as dilactide or lactide (LA). This chapter describes preparation of polymers and copolymers of LAs with different structures, using polycondensation and ROP. Typical comonomers and polymers which are used for lactic acid or LA copolymerization include glycolic acid or glycolide, poly(ethylene glycol) or poly(ethylene oxide), and so on. PLAs having amino, carboxyl, or other functional groups are well reported in the literature. These functional groups can be utilized for chemical modification or as binding sites for biomolecules to impart selective binding and adhesion. PLA and its copolymers especially when used for biological applications, besides requirement of optimization of mechanical properties by engineering at the molecular level, also demands a fast degradation polymer rate.

  • 28.
    Albinsson, Emmy
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Tafesse Belachew, Helina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Swaich, Jasmin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Juhlin, Hannah
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Novel materials from lignocellulosic sources- can they replace thermoplastics?2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Plastic waste is a severe environmental problem in today's society which has been noticed and discussed during the last couple of years. A constant increase of production over the last decades hasled to a large amount of plastic waste ending up in oceans as microplastics. With harder restrictions of plastic use from the European Parliament, alternative plastics that are bio-based and therefore degradable have increased in demand. The aim of this project was therefore to synthesize alignocellulose-based material which contains the minimum amount of latex, the plastic component, while still satisfying the same requirements as a thermoplastic. The original idea was to create the latex with PISA-RAFT technique however, this was not possible since the needed materials could not be delivered due to COVID-19, therefore radical emulsion polymerization was carried out.

    Two latexes were synthesized to create composites with wheat-straw, latex A and latex B. Both latexes consisted of 75% of monomer vinyl acetate (VAc) which was the main component but with different weight percentages of monomers methacrylic acid (MAA) and methyl methacrylate (MMA). Latex A consisted of 20 % MAA and 5% MMA and latex B consisted of 20% MMA and 5% MAA. Latex A and latex B were then mixed with wheat straw to create composites. Due to problems withthe wheat-straw composites one additional composite was created to be able to do all of the analyses. This composite was created by using filter paper as biofiber to mix with the two different latexes. Various characterization analyses including FE-SEM, DLS, DSC, FTIR, NMR, TGA and tensile tests were performed on the composites.

    The NMR and DSC analyses indicated that the actual composition of monomers differs from the theoretical composition and demonstrates that the presence of MAA is hard to detect. This is due to the DSC value for latex A experimental Tg being lower than latex B experimental Tg when latex A consists of more MAA which has a higher detected Tg. During the NMR analysis MAA was also not detected in either latex A nor latex B. The analyses of FTIR contradicts the NMR and DSC analyses hence peaks believed to be from MAA are detected. When comparing the analysis for latex A and B, DLS analysis resulted in latex A having a low PDI and a bigger emulsion sphere size which is preferred when producing composites. The tensile test resulted in latex B achieving the higher values for Young’s modulus and max stress while latex A had a higher value for strain at break. The TGA and DSC analysis however resulted in latex B having a higher Tg and higher thermal stability. The overall analyses indicated that latex B was the most optimal choice for composite production with aslight difference.

    The analysis of the composites indicated by FE-SEM that the interaction between latex and filter paper were higher than for latex and wheat straw. A total of four wheat-straw composites were created with the weight-ratio of wheat-straw:latex, 50:50 and 75:50 for both latex A and B. Due to not being able to grind the wheat straw to the minimum size needed to create composites only FE-SEM and FTIR analyses of the wheat-straw composites could be made. Because of this no conclusion could be made whether the 75:50 or 50:50 weight ratio was the most optimal.

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  • 29.
    Alexakis, Alexandros Efraim
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Nanolatexes: a versatile toolbox for cellulose modification2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cellulosic materials are widely used in our everyday lives, ranging from paperand packaging to biomedical applications. However, in most applications, cellulose must coexist with hydrophobic polymers which can be challenging due to its hydrophilic character. This has encouraged the exploration of chemical and physical modifications of cellulose.

    The projects included in this thesis focus on the physical modification of cellulosic materials with tailor-made, highly versatile colloidal nanoparticles synthesized in water, called nanolatexes. Their synthesis is based on the combination of the reversible addition-fragmentation chain transfer (RAFT) polymerization with polymerization-induced self-assembly (PISA). The bridging of these techniques results in the formation of amphiphilic diblock copolymers which self-assemble in water forming a variety of morphologies. Spheres, worms and vesicles with pH-responsive shell polymers were prepared to investigate the parameters that tune these morphological transitions. Less investigated parameters such as the chemical composition of the RAFT agent were studied which resulted in the formation of bimodal nanolatexes with opal-like characteristics in a reproducible manner. 

    A fundamental investigation of the parameters that govern the adsorption of cationically charged nanolatexes onto silica and regenerated TEMPO-oxidized cellulose model surfaces was also performed. The combination of gravimetric and a reflectometric techniques revealed the complexity of that model surface. Both the size and the charge density of the nanolatexes were found to influence their adsorption. The information gained from this study was implemented in the preparation of cellulose nanofibril (CNF)-nanocomposites with low contents of nanolatexes. It was found that when the nanolatex content was below 1 wt% the mechanical profile of the CNF-nanocomposites was improved. 

    Finally, wood-based components were used to replace fossil-based monomers in nanolatexes. They were readily adsorbed onto cellulose filter papers and annealed, thus demonstrating their film formation capacity. Nanolatexes comprised of a wood-based shell polymer have a promising high-end application profile, as showcased by their interactions with Cu(II) ions, where nanolatexes prevented the formation of Cu(II) ion aggregates. 

    The results summarized in this thesis add to the understanding on physical modification of cellulose and are envisaged to further promote the utilization of wood-based monomers in the production of the polymers for high-end applications.

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  • 30.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Ayyachi, Thayanithi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Mousa, Maryam
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Olsen, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    2-Methoxy-4-Vinylphenol as a Biobased Monomer Precursor for Thermoplastics and Thermoset Polymers2023In: Polymers, E-ISSN 2073-4360, Vol. 15, no 9, article id 2168Article in journal (Refereed)
    Abstract [en]

    To address the increasing demand for biobased materials, lignin-derived ferulic acid (FA) is a promising candidate. In this study, an FA-derived styrene-like monomer, referred to as 2-methoxy-4-vinylphenol (MVP), was used as the platform to prepare functional monomers for radical polymerizations. Hydrophobic biobased monomers derived from MVP were polymerized via solution and emulsion polymerization resulting in homo- and copolymers with a wide range of thermal properties, thus showcasing their potential in thermoplastic applications. Moreover, divinylbenzene (DVB)-like monomers were prepared from MVP by varying the aliphatic chain length between the MVP units. These biobased monomers were thermally crosslinked with thiol-bearing reagents to produce thermosets with different crosslinking densities in order to demonstrate their thermosetting applications. The results of this study expand the scope of MVP-derived monomers that can be used in free-radical polymerizations toward the preparation of new biobased and functional materials from lignin.

  • 31.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Engström, Joakim
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Stamm, Arne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Riazanova, Anastasia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Wallenberg Wood Sci Ctr WWSC, Tekn Ringen 56-58, SE-10044 Stockholm, Sweden..
    Brett, Calvin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, Hamburg, 22603, Germany.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, Hamburg, 22603, Germany.
    Syrén, Per-Olof
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Fogelström, Linda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Reid, Michael S.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Modification of cellulose through physisorption of cationic bio-based nanolatexes - comparing emulsion polymerization and RAFT-mediated polymerization-induced self-assembly2021In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 23, no 5, p. 2113-2122Article in journal (Refereed)
    Abstract [en]

    The polymerization of a bio-based terpene-derived monomer, sobrerol methacrylate (SobMA), was evaluated in the design of polymeric nanoparticles (nanolatexes). Their synthesis was accomplished by using emulsion polymerization, either by free-radical polymerization in the presence of a cationic surfactant or a cationic macroRAFT agent by employing RAFT-mediated polymerization-induced self-assembly (PISA). By tuning the length of the hydrophobic polymer, it was possible to control the nanoparticle size between 70 and 110 nm. The average size of the latexes in both wet and dry state were investigated by microscopy imaging and dynamic light scattering (DLS). Additionally, SobMA was successfully copolymerized with butyl methacrylate (BMA) targeting soft-core nanolatexes. The comparison of the kinetic profile of the cationically stabilized nanolatexes highlighted the differences of both processes. The SobMA-based nanolatexes yielded high T-g similar to 120 degrees C, while the copolymer sample exhibited a lower T-g similar to 50 degrees C, as assessed by Differential Scanning Calorimetry (DSC). Thereafter, the nanolatexes were adsorbed onto cellulose (filter paper), where they were annealed at elevated temperatures to result in polymeric coatings. Their morphologies were analysed by Field Emission Scanning Electron Microscopy (FE-SEM) and compared to a commercial sulfate polystyrene latex (PS latex). By microscopic investigation the film formation mechanism could be unravelled. Water contact angle (CA) measurements verified the transition from a hydrophilic to a hydrophobic surface after film formation had occured. The obtained results are promising for the toolbox of bio-based building blocks, focused on sobrerol-based monomers, to be used in emulsion polymerizations either for tailored PISA-latexes or facile conventional latex formation, in order to replace methyl methacrylate or other high T-g-monomers.

  • 32.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    pH-Responsive nanolatexes stabilized by statistical copolymers obtained by RAFT-mediated PISAManuscript (preprint) (Other academic)
  • 33.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Riazanova, Anastasia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Bio-based nanolatexes prepared via polymerization-induced self-assembly: targeting heavy metal capturing applicationsManuscript (preprint) (Other academic)
  • 34.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wilson, Olivia R.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Bimodal nanolatexes prepared via polymerization-induced self-assembly: losing control in a controlled mannerManuscript (preprint) (Other academic)
  • 35.
    Alexakis, Alexandros Efraim
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wilson, Olivia R.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Bimodal nanolatexes prepared via polymerization-induced self-assembly: losing control in a controlled manner2023In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 14, no 19, p. 2308-2316Article in journal (Refereed)
    Abstract [en]

    The combination of reversible addition-fragmentation chain-transfer (RAFT) polymerization with polymerization-induced self-assembly (PISA) is known to yield monodisperse nanolatexes. Interestingly, based on the results of the current study, reproducible bimodal nanolatexes were shown to be the result of chain extension of protonated poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) with methyl methacrylate (MMA) in water when aiming for a longer hydrophobic block, for which we provide the first imaging data to our knowledge. The bimodality was found to be induced by the hydrophilic Z-group of the RAFT agent, which has been reported in the literature to be the cause of bimodal molecular weight distributions in RAFT-mediated PISA in emulsion polymerization. Moreover, the advantages of such reproducible bimodal size distribution nanolatexes in coating applications were investigated briefly, underlining the possibilities of their one-pot synthesis. It was found that when bimodal nanolatexes are adsorbed onto cellulose filter paper, the contact angle against water is higher compared to chemically similar monomodal nanolatexes. Also, the morphological arrangement was found to be dependent on the drying protocol. This study aims to expand our understanding on bimodality and the identification of parameters that could promote it on demand to target high-end applications.

  • 36.
    Alin, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Microwave heating effects on degradation and migration of additives from polypropylene packaging2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The effect of different food types, polymer qualities and microwaves on the overall and specific migration during microwave heating of plastic packaging was investigated to better understand the packaging-food interactions and the effect of microwaves on food packaging. This work focuses on the migration of chemical compounds to food simulants from commercially available polypropylene packages. Packages used were made of polypropylene homopolymer (PP), co-polymer (PP-C) and random co-polymer (PP-R). Polymers matrix changes were monitored by following possible changes in crystallinity after microwave heating. Antioxidants Irgafos 168 and Irganox 1010 were present in all the three PP packages. Other volatiles, primarily degradation products of antioxidants, were also detected and identified in the unaged packages. Significant antioxidant degradation took place during microwave heating of the packages in the fatty food simulants 90/10 isooctane/ethanol and ethanol resulting in the formation and migration of degradation products while no degradation of antioxidants was detected during conventional heating of the packages in the fatty food simulants. Antioxidant Irgafos 168 and Irganox 1010 migration rates were otherwise similar during microwave heating as during conventional heating to the fatty food simulants and antioxidant diffusion coefficients were similar to earlier established values obtained during conventional heating. Antioxidant migration rates from the three polymers to fatty food simulants differed largely with respect to PP type and increased with decreasing degree of crystallinity in the materials, PP-R showing the highest migration rate. Swelling in isooctane food simulant caused the antioxidant diffusion coefficients to increase by factors of 100-1000 at 80 ºC and decreased the temperature dependence of antioxidant migration. It also increased the overall migration to above established overall migration limits during both microwave and conventional heating. Electrospray ionization mass spectrometry (ESI-MS) was shown to be a valuable new tool for additive migration analysis of compounds not detectable by HPLC or GC-MS.

  • 37.
    Alin, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Migration from plastic food packaging during microwave heating2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Microwave heating of food has increased rapidly as a food processing technique. This increases the concern that chemicals could migrate from food packaging to food. The specific effect of microwave heating in contrast to conventional heating on overall and specific migration from common plastic food storage boxes was studied in this work. The purpose was especially to determine the interaction effects of different plastics in contact with different types of foods during microwave heating. The study focused on polycarbonate (PC), poly(ethylene terephthalate) (PET), polypropylene homo-polymer (PP), co-polymer (PP-C) and random co-polymer (PP-R) packages. The migration determinations were evaluated at controlled times and temperatures, using a MAE device. The migrants were analyzed by GC-MS and HPLC. ESI-MS was evaluated as a new tool for migration determinations. Food/food simulant absorption and changes in degree of crystallinity during heating were also followed.

    Significant degradation of antioxidants Irgafos 168 and Irganox 1010 in PP packages occurred during microwave heating of the packages in food simulants containing ethanol, resulting in the formation of antioxidant degradation products. Degradation of PC by Fries chain rearrangement reaction leading to formation of 9,9-dimethylxanthene, and transesterification of PET leading to formation of diethyl terephthalate, were also observed after microwave heating the packages in ethanol and 90/10 isooctane/ethanol. These reactions were not observed during conventional heating of the packages at the same temperature, or after microwave heating of the packages in liquid food (coconut milk). The microwave heating also significantly increased the migration of cyclic oligomers from PET into ethanol and isooctane at 80 °C. Migration of compounds into coconut milk was slightly lower than calculated amounts using the EU mathematical model to predict migration of additives into foodstuffs. The results thus show that the use of ethanol as a fat food simulant during microwave heating can lead to a significant overestimation of migration as well as degradation of polymer or the incorporated additives.

    Some other detected migrants were dimethylbenzaldehyde, 4-ethoxy-ethyl benzoate, benzophenone, m-tert-butyl phenol and 1-methylnaphthalene. All identified migrants with associated specific migration limit (SML) values migrated in significantly lower amounts than the SML values during 1 h of microwave heating at 80 °C. The antioxidant diffusion coefficients in PP and PP co-polymers showed larger relative differences than the corresponding degrees of crystallinity in the same polymers and PP-R showed by far the fastest migration of antioxidants.

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  • 38.
    Alin, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Combined Chromatographic and Mass Spectrometric Toolbox for Fingerprinting Migration from PET Tray during Microwave Heating2013In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 61, no 6, p. 1405-1415Article in journal (Refereed)
    Abstract [en]

    A combined chromatographic and mass spectrometric toolbox was utilized to determine the interactions between poly(ethylene terephthalate) (PET) food packaging and different food simulants during microwave heating. Overall and specific migration was determined by combining weight loss measurements with gas chromatography-mass spectrometry (GC-MS) and electrospray ionization mass spectrometry (ESI-MS). This allowed mapping of low molecular weight migrants in the molecular range up to 2000 g/mol. Microwave heating caused significantly faster migration of cyclic oligomers into ethanol and isooctane as compared to migration during conventional heating at the same temperature. This effect was more significant at lower temperature at which diffusion rates are generally lower. It was also shown that transesterification took place between PET and ethanol during microwave heating, leading to formation of diethyl terephthalate. The detected migrants included cyclic oligomers from dimer to hexamer, in most cases containing extra ethylene glycol units, and oxidized Irgafos 168. ESI-MS combined with CID MS-MS was an excellent tool for structural interpretation of the nonvolatile compounds migrating to the food simulants. The overall migration was below the overall migration limit of 10 mg/dm(2) set by the European commission after 4 h of microwave heating at 100 degrees C in all studied food simulants.

  • 39.
    Alin, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Microwave heating causes rapid degradation of antioxidants in polypropylene packaging leading to greatly increased specific migration to food simulants as shown by ESI-MS and GC-MS2011In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 59, no 10, p. 5418-5427Article in journal (Refereed)
    Abstract [en]

    Microwave heating of commercial microwavable polypropylene packaging in contact with fatty food simulants caused significant antioxidant degradation and increased specific migration as shown by electrospray ionization-mass spectrometry (ESI-MS) and gas chromatography-mass spectrometry (GC-MS). Degradation of the antioxidants Irgafos 168 and Irganox 1010 was not detected during conventional heating of polypropylene packaging at the same temperature. The migration into aqueous food simulants was primarily restricted by the water solubility of the migrants. Using isooctane as fatty food simulant caused significant swelling and greatly enhanced overall migration values compared to the other fatty food simulant, 99.9% ethanol, or the aqueous food simulants 10% ethanol, 3% acetic acid, or water. ESI-MS spectra clearly reflected the overall migration values, and the number and amount of compounds detected decreased as the hydrophilicity of the food simulant increased. ESI-MS was shown to be an excellent tool for the analysis of semivolatile migrants and a good complement to GC-MS analysis of volatile migrants.

  • 40.
    Alin, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Migration from polycarbonate packaging to food simulants during microwave heating2012In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 97, no 8, p. 1387-1395Article in journal (Refereed)
    Abstract [en]

    The interactions between polycarbonate (PC) packaging and different food simulants during microwave heating were evaluated by identifying the compounds migrating into aqueous, alcoholic and fatty food simulants. The migration of compounds, such as 9,9-dimethylxanthene and m-tert-butyl-phenol, from the PC package to ethanol and isooctane increased significantly during microwave heating as compared to conventional heating. The increase in migration can be explained by degradation caused by microwave heating and/or stronger food simulant interactions. Depending on the food simulant the migrants were quantified either by multiple headspace–solid-phase micro-extraction (MHS-SPME) or direct injection in combination with gas chromatography-mass spectrometry. A partial least squares (PLS) regression model was developed to predict the extraction efficiency for headspace–solid-phase micro-extraction (HS-SPME) of food package migrants from the analyte properties. The most significant property for prediction of the enrichment factors was the octanol-water partition coefficient (log Kow). Polydimethylsiloxane (PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibers were compared for the extraction of the migrants. High correlation was found between the PDMS and PDMS/DVB enrichment factors (R2=0.98), but the extraction by PDMS/DVB fiber was much more efficient compared to the extraction by PDMS fiber. The detection limits after SPME extraction by PDMS/DVB fiber were 1, 0.1 and 3 ng/L for 4-ethoxy-ethyl-benzoate, 2,4-di-tert-butyl-phenol and benzophenone, respectively.

  • 41.
    Alin, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Type of Polypropylene Material Significantly Influences the Migration of Antioxidants from Polymer Packaging to Food Simulants During Microwave Heating2010In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 118, no 2, p. 1084-1093Article in journal (Refereed)
    Abstract [en]

    Three different polypropylene materials, polypropylene homopolymer (PP), propylene-ethylene random copolymer (PP-R), and propylene-ethylene copolymer (PP-C) are commonly used in plastic containers designed for microwave heating of food. Migration of antioxidants, Irganox 1010 and Irgafos 168, from PP. PP-R, and PP-C during microwave heating in contact with different food simulants was investigated by utilizing microwave assisted extraction (MAE) and high performance liquid chromatography (HPLC). The polypropylene material significantly influenced the migration rate, which decreased in the order of increasing degree of crystallinity in the materials. PP homopolymer was the most migration resistant of the studied materials especially in contact with fatty food simulants. The use of isooctane as fatty food simulant resulted in rapid depletion of antioxidants, while migration to another fatty food simulant, 96% ethanol, was much more limited. Migration to aqueous and acidic food simulants was in most cases under the detection limits irrespective of microwaving time and temperature. The diffusion coefficients were similar to what have been found previously under similar conditions but without microwaves. The effect of swelling was shown by the large increase in the calculated diffusion coefficients when isooctane was used as food simulant instead of 96% ethanol. (C) 2010 Wiley Periodicals, Inc. I Appl Polym Sci 118: 1084-1093,2010

  • 42.
    Alipour, Nazanin
    KTH, School of Chemical Science and Engineering (CHE).
    Migration of different additives from polyethylen2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Insecticidal polymer nets are used to combat malaria. It combines polyethylene fibers and two chemicals, deltamethrin (DM) and a synergist piperonyl butoxide (PBO) which increases efficacy of deltamethrin. The migration and evaporation of DM and PBO through polyethylene was studied in this report. The crystallinity and melting temperature of pristine DM, a prepared polymer compound and Vestergaard samples were characterized by differential scanning calorimetry (DSC). It was found that DM does not crystallize and remains liquid after cooling to room temperature. A small depression in melting temperature of the polymer was observed when samples were covered by a layer of DM. Rate constants and activation energies of evaporation were determined by thermogravimetry (TG) including pristine DM, PBO and their solution and also PE compound and Vestergaard samples. Higher rate constant for DM and PBO solution was observed in comparison with pure DM and PBO. The migration of DM and PBO from the polyethylene was studied in liquid water and air with different relative humidity (60 and 80%) at 80 ⁰C. Water caused degradation of the DM present in the material and generated product species containing nitro and amine groups. Besides, the degraded products including some undegraded DM formed a layer on the surface of the material (blooming). Liquid chromatography (HPLC) and infrared spectroscopy (IR) showed faster migration of the active species in liquid water than in air with 60 and 80% RH; (approximately 7 times for DM and 2 times for PBO). Some DM agglomerates was observed on the plate surface after exposure to air with 80 % RH.

  • 43.
    Alipour, Nazanin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Enebro, J.
    Strömberg, Emma
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Qualitative characterization of nanoclay particle emissions from PP nanocomposites after thermal degradation2015In: 20th International Conference on Composite Materials, ICCM 2015, International Committee on Composite Materials , 2015Conference paper (Refereed)
    Abstract [en]

    The use of nanomaterials in polymeric materials is a rapidly expanding field, and the polymer nanocomposites are being introduced into various markets. But there is still little known about the fate of nanocomposites and nanoparticles during service life and end-of-life of the materials. To avoid possible environmental, health and safety problems, simulating different scenarios for nanoparticles release from the polymer matrix plays a key role in commercialization of these advanced materials. The polymer/nanoclay nanocomposites show superior material properties in comparison with the pure polymers, such as improved mechanical properties, heat resistance, flame retardancy and decreased gas permeability. Polypropylene (PP) nanocomposites have attracted a considerable interest due to the material's low cost, low density and extensive production volumes. In this study, in order to obtain reliable results regarding the release of nanoclays from PP nanocomposites, homogenous composite with predetermined content of nanoclay was produced and characterized to obtain information regarding content, dispersion and size of the nanoclays in the matrix. The PP nanocomposite was degraded under controlled conditions and the surface morphology as well as oxidation of the material was characterized with scanning electron microscopy (SEM) and infrared spectroscopy during degradation. A prototype environmental chamber was designed in order to collect nano-sized particles in a controlled manner and subsequent characterization of the released or formed particles was performed with transmission electron microscopy (TEM) and the exposed nanocomposite was analysed with thermogravimetric analysis (TGA). 

  • 44.
    Alipour, Nazanin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Gedde, Ulf W
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Yu, Shun
    Roth, Stephan
    Brüning, Karsten
    Vieyres, Arnaud
    Schneider, Konrad
    Structure and properties of polyethylene-based and EVOH-based multilayered films with layer thicknesses of 150 nm and greater2015In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 64, p. 36-51Article in journal (Refereed)
    Abstract [en]

    This paper presents the structure and properties of two multilayered systems where polymers in adjacent layers were either miscible or immiscible. The miscible system consisted of 2, 17, 18, 24 and nominally 288 layers of alternating low-density (LDPE) and low-density/linear-low density (mPE) polyethylene layers with observed thicknesses ranging from 150 nm to 20 urn. The immiscible system consisted of 5 and 19 layer films with a combination of poly(ethylene-co-vinyl alcohol) (EVOH) (thickness: 9 and 1 gm, respectively), LDPE (17 and 7 gm) and a polyethylene adhesive (3 and 1 gm). The purpose of the multi-layering was to increase the crack growth resistance and, in the EVOH-based system, to decrease the oxygen transmission rate. Indeed, the crack growth resistance, as measured on tensile-tested notched films, increased with increasing number of layers. The thinnest polyethylene and polyethylene adhesive layers showed a clear ductile failure when fractured even in liquid nitrogen. Simultaneous synchrotron wide-angle/small-angle X-ray scattering and tensile testing indicated no new deformation features with changes in the layer thickness. The oxygen permeability was the same in the 5- and 19-layer EVOH-based films, but the uptake of n-hexane was strongly reduced in the 19-layer films, demonstrating the effective protective role of the EVOH layers. The n-hexane desorption data of the 2-layer LDPE/mPE film was successfully modeled using the diffusivities and solubilities of the single layers. Crystallization was slower and more confined in the films with thinner layers. The interlayer mixing in the melt (measured by isothermal crystallization from melts of initially layered polyethylene-based systems) was, as expected, significantly faster in the 24- and 288-multilayer films than in the 2-layer film.

  • 45.
    Alipour, Nazanin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Vinneras, Bjorn
    SLU Swedish Univ Agr Sci, Dept Energy & Technol, POB 7032, SE-75007 Uppsala, Sweden..
    Gouanve, Fabrice
    Univ Lyon 1, Univ Lyon, Ingn Mat Polymeres, CNRS,UMR 5223, 15 Bd Andre Latarjet, F-69622 Villeurbanne, France..
    Espuche, Eliane
    Univ Lyon 1, Univ Lyon, Ingn Mat Polymeres, CNRS,UMR 5223, 15 Bd Andre Latarjet, F-69622 Villeurbanne, France..
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.
    A Protein-Based Material from a New Approach Using Whole Defatted Larvae, and Its Interaction with Moisture2019In: Polymers, E-ISSN 2073-4360, Vol. 11, no 2, article id 287Article in journal (Refereed)
    Abstract [en]

    A protein-based material created from a new approach using whole defatted larvae of the Black Soldier fly is presented. The larvae turn organic waste into their own biomass with high content of protein and lipids, which can be used as animal feed or for material production. After removing the larva lipid and adding a plasticizer, the ground material was compression molded into plates/films. The lipid, rich in saturated fatty acids, can be used in applications such as lubricants. The amino acids present in the greatest amounts were the essential amino acids aspartic acid/asparagine and glutamic acid/glutamine. Infrared spectroscopy revealed that the protein material had a high amount of strongly hydrogen-bonded beta-sheets, indicative of a highly aggregated protein. To assess the moisture-protein material interactions, the moisture uptake was investigated. The moisture uptake followed a BET type III moisture sorption isotherm, which could be fitted to the Guggenheim, Anderson and de Boer (GAB) equation. GAB, in combination with cluster size analysis, revealed that the water clustered in the material already at a low moisture content and the cluster increased in size with increasing relative humidity. The clustering also led to a peak in moisture diffusivity at an intermediate moisture uptake.

  • 46.
    Alizadehgiashi, Moien
    et al.
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Nemr, Carine R.
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Chekini, Mahshid
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Ramos, Daniel Pinto
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Mittal, Nitesh
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Fluid Physics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada.
    Ahmed, Sharif U.
    Univ Toronto, Dept Pharmaceut Sci, Toronto, ON M5S 3M2, Canada..
    Khuu, Nancy
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada..
    Kelley, Shana O.
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada.;Univ Toronto, Dept Pharmaceut Sci, Toronto, ON M5S 3M2, Canada.;Univ Toronto, Inst Biomat & Biomed Engn, Toronto, ON M5S 3G9, Canada..
    Kumacheva, Eugenia
    Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada.;Univ Toronto, Inst Biomat & Biomed Engn, Toronto, ON M5S 3G9, Canada.;Univ Toronto, Dept Chem Engn & Appl Chem, Toronto, ON M5S 3E5, Canada..
    Multifunctional 3D-Printed Wound Dressings2021In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 15, no 7, p. 12375-12387Article in journal (Refereed)
    Abstract [en]

    Personalized wound dressings provide enhanced healing for different wound types; however multicomponent wound dressings with discretely controllable delivery of different biologically active agents are yet to be developed. Here we report 3D-printed multicomponent biocomposite hydrogel wound dressings that have been selectively loaded with small molecules, metal nanoparticles, and proteins for independently controlled release at the wound site. Hydrogel wound dressings carrying antibacterial silver nanoparticles and vascular endothelial growth factor with predetermined release profiles were utilized to study the physiological response of the wound in a mouse model. Compared to controls, the application of dressings resulted in improvement in granulation tissue formation and differential levels of vascular density, dependent on the release profile of the growth factor. Our study demonstrates the versatility of the 3D-printed hydrogel dressings that can yield varied physiological responses in vivo and can further be adapted for personalized treatment of various wound types.

  • 47. Altuna, Facundo I.
    et al.
    Riccardi, Carmen C.
    Marin Quintero, Diana C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Ruseckaite, Roxana A.
    Stefani, Pablo M.
    Effect of an Anhydride Excess on the Curing Kinetics and Dynamic Mechanical Properties of Synthetic and Biogenic Epoxy Resins2019In: International Journal of Polymer Science, ISSN 1687-9422, E-ISSN 1687-9430, article id 5029153Article in journal (Refereed)
    Abstract [en]

    This work analyzes the effect of the anhydride excess on the nonisothermal curing kinetics and on the final properties of synthetic and biobased epoxy resins. Diglycidyl ether of bisphenol A (DGEBA) and epoxidized soybean oil (ESO) were crosslinked using methyltetrahydrophthalic anhydride (MTHPA) as a curing agent and 1-methylimidazole (1MI) as an initiator. It was shown that the ESO/MTHPA/1MI system reacts slower than the DGEBA/MTHPA/1MI system, giving place to a more significant evaporation of the curing agent during the reaction. As a result, an excess of anhydride improves the final thermal properties of the ESO/MTHPA/1MI network, contrary to the behavior observed for DGEBA/MTHPA/1MI. The knowledge of the kinetics of the curing process and the optimal amount of the curing agent for each system is of critical importance for a more efficient processing of these materials.

  • 48. Amanizadeh, Farhad
    et al.
    Akhlaghi, Shahin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Mobarakeh, Hamid Salehi
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Starve fed emulsion copolymerization of vinyl acetate and 1-hexene at ambient pressure2014In: Polymer international, ISSN 0959-8103, E-ISSN 1097-0126, Vol. 63, no 10, p. 1850-1855Article in journal (Refereed)
    Abstract [en]

    A novel emulsion copolymer of vinyl acetate (VAc) and 1-hexene was synthesized at ambient pressure. The feeding technique, initiation system and reaction time of the copolymerization were optimized based on molecular characteristics such as the weight contribution of 1-hexene in the copolymer chains and glass transition temperature (T-g) as well as on bulk properties like minimum film-formation temperature (MFFT) and solid content. According to nuclear magnetic resonance spectroscopy and differential scanning calorimetry results, the combination of starve feeding and redox initiation, within a reaction time of 4h, effectively led to the copolymerization at ambient pressure between highly reactive polar VAc monomers and non-polar 1-hexene monomers of low reactivity. The copolymer showed a lower T-g and MFFT, and a reasonable solid content compared to the poly(vinyl acetate) (PVAc) homopolymer. The consumption rate, hydrolysis of acetate groups and chain transfer reactions during the polymerization were followed using infrared spectroscopy. Based on the results, the undesirable reactions between the VAc blocks were hindered by the neighbouring 1-hexene molecules. Tensile testing revealed an improvement in the toughness and elongation at break of VAc-1-hexene films compared to PVAc films.

  • 49.
    Amaral, Sarah da Costa
    et al.
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil..
    Barbieri, Shayla Fernanda
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil..
    Ruthes, Andrea C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience. UF, GCREC, Dept Entomol & Nematol, Wimauma, FL USA..
    Bark, Juliana Mueller
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil..
    Brochado Winnischofer, Sheila Maria
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil.;Univ Fed Parana, Dept Biochem & Mol Biol, PB 19046, BR-81531980 Curitiba, PR, Brazil.;Univ Fed Parana, Postgrad Program Cellular & Mol Biol, BR-81531980 Curitiba, PR, Brazil..
    Meira Silveira, Joana Lea
    Univ Fed Parana, Sect Biol Sci, Postgrad Program Biochem Sci, BR-81531990 Curitiba, PR, Brazil.;Univ Fed Parana, Dept Biochem & Mol Biol, PB 19046, BR-81531980 Curitiba, PR, Brazil..
    Cytotoxic effect of crude and purified pectins from Campomanesia xanthocarpa Berg on human glioblastoma cells2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 224, article id UNSP 115140Article in journal (Refereed)
    Abstract [en]

    A new source of pectin with a cytotoxic effect on glioblastoma cells is presented. A homogeneous GWP-FP-S fraction (M-w, of 29,170 g mol(-1)) was obtained by fractionating the crude pectin extract (GW) from Campomanesia xanthocarpa pulp. According to the monosaccharide composition, the GWP-FP-S was composed of galacturonic acid (58.8%), arabinose (28.5%), galactose (11.3%) and rhamnose (1.1%), comprising 57.7% of homogalacturonans (HG) and 42.0% of type I rhamnogalacturonans (RG-I). These structures were characterized by chromatographic and spectroscopic methods; GW and GWP-FP-S fractions were evaluated by MIT and crystal violet assays for their cytotoxic effects. Both fractions induced cytotoxicity (15.55-37.65%) with concomitant increase in the cellular ROS levels in human glioblastoma cells at 25-400 mu g mL(-)(1), after 48 h of treatment, whereas no cytotoxicity was observed for normal NIH 3T3 cells. This is the first report of in vitro bioactivity and the first investigation of the antitumor potential of gabiroba pectins.

  • 50.
    Aminlashgari, Nina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    SALDI-MS Method Development for Analysis of Pharmaceuticals and Polymer Degradation Products2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Surface assisted laser desorption ionization-mass spectrometry (SALDI-MS) was evaluated as a new tool for analysis of polymer degradation products. A SALDI method was developed enabling rapid analysis of low molecular mass polyesters and their degradation products. In addition, the possibility to utilize nanocomposite films as easy-to-handle surfaces for analysis of pharmaceutical compounds was investigated.

    Poly(ε-caprolactone) was used as a model compound for SALDI-MS method development. The signal-to-noise values obtained by SALDI-MS were 20 times higher compared to traditional matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) of the same samples with 2,5-dihydroxybenzoic acid as a matrix. Halloysite nanoclay and magnesium oxide showed best potential as surfaces and clean backgrounds in the low mass range were observed. The SALDI-MS method for the analysis of polyester degradation products was also verified by electrospray ionization-mass spectrometry (ESI-MS). An advantage over ESI-MS is the possibility to directly analyze degradation products in buffer solutions. Compared to gas chromatography-mass spectrometry (GC-MS) it is possible to analyze polar compounds and larger molecular mass ranges at the same time as  complicated extraction steps are avoided.

    The possibility to use nanocomposite films as surfaces instead of free nanoparticles was evaluated by solution casting of poly(lactide) (PLA) films with eight inorganic nanoparticles. The S/N values of the pharmaceutical compounds, acebutolol, propranolol and carbamazepine, analyzed on the nanocomposite surfaces were higher than the values obtained on the surface of plain PLA showing that the nanoparticles participated in the ionization/desorption process even when they are immobilized. Beside the ease of handling, the risk for instrument contamination is reduced when nanocomposites are used instead of free nanoparticles. The signal intensities depended on the type of drug, type and concentration of nanoparticle. PLA with 10 % titanium oxide or 10 % silicon nitride functioned best as SALDI-MS surfaces.

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