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  • 1. 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.

  • 2.
    Agfors, Gunnar
    et al.
    Ledamot av IVA.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Grenthe, Ingmar
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ödberg, Lars
    et, al
    KEMI: den gränslösa vetenskapen2011Book (Other (popular science, discussion, etc.))
    Abstract [sv]

    Kemi – handlar inte det bara om farliga ämnen och onödiga tillsatser? Det är kanske bildenmånga har av kemi, men faktum är att utan kemi skulle vi inte ha det höga välstånd vi har i dag.Tack vare kemisk kunskap har vi tillgång till läkemedel som botar sjukdomar och lindrar smärta– med hjälp av syntetiska antibiotika kan infektionssjukdomar som tidigare var dödliga botas,magsår kan behandlas utan dyra och plågsamma operationer och många cancerformer kanframgångsrikt behandlas med syntetiska preparat. Konstgödsel och medel som hindrar skadeinsektergör att skördar kan ökas och svälten i världen därigenom begränsas. Tack vare kemin harvi även tillgång till alla de material vi behöver för att tillverka allt från kläder, rengöringsprodukteroch kosmetika till bilar, TV-apparater och reservdelar till kroppen. Det är genom kemisk syntes vikan framställa dessa och alla de övriga produkter vi behöver för vårt dagliga liv och det är keminsom visar vägen till hållbar produktion som utnyttjar förnybara råvaror och ger minimala mängderavfall. Kemisk kunskap är också oumbärlig för utveckling av nanoteknik och medicinskdiagnostik och andra till kemin angränsande områden. Kemin bidrar alltså till att finna lösningartill många av de komplexa globala problem vi står inför: hälsa, klimat, brist på råvaror, utnyttjandetav nya energikällor och tillgång till livsmedel för att föda jordens ökande befolkning.

    DET ÄR OM ALLT DETTA DEN HÄR BOKEN HANDLAR.

  • 3.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Design of green materials by building-in a controlled behavior2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247Article in journal (Other academic)
  • 4.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Frontiers in Biomacromolecules: Functional Materials from Nature2012In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 13, no 12, p. 3901-3901Article in journal (Other academic)
  • 5.
    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.

  • 6.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    David, G.
    Strandberg, C.
    Bilba, D.
    Paduraru, C.
    Synthesis of core-shell structured carboxylated microparticles with a straightforward procedure and their evaluation as a polymer support2005In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 43, no 23, p. 5889-5898Article in journal (Refereed)
    Abstract [en]

    Poly(trimethylolpropane trimethacrylate) microspheres with a narrow size distribution were obtained by precipitation polymerization. They were subsequently modified by surface grafting with acrylic acid in a polar ethanol-water reaction medium, without stabilizer, yielding core-shell particles with diameters in the micrometer range. The resulting polymeric material was characterized by SEM and potentiometric titration, FTIR spectroscopy, and thermal analysis. It was shown that the particle characteristics (size, size distribution, and functionality) obtained by this straightforward procedure can be controlled by modifying the synthesis parameters (monomer concentration, agitation rate, and temperature). The high functionality, the chemical and physico-mechanical stability, as well as the possibility to control the performances of the resulting polymeric materials by synthesis allow its applications in various areas. Envisaging separation and catalysis domains, Cu(II), Cd(II), and Cr(III) uptake capacity from aqueous solutions was investigated under noncompetitive conditions as a function of synthesized particle functionality, time, and pH range. It was also found that the addition of the carboxylated. microparticles to polyethylene stabilized with alpha-tocopherol improved the thermo-oxidative behaviour of the polymeric material.

  • 7.
    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.
    Barrier layers for packaging laminates and packaging laminates comprising such barrier layers2009Patent (Other (popular science, discussion, etc.))
  • 8.
    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.
    Efficient conversion of wood hydrolysates into renewable materials2012In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 244Article in journal (Other academic)
  • 9.
    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)
  • 10.
    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)
  • 11.
    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.
    Vedrester blir förnybar råvara2009In: Miljöforskning, ISSN 1650-4925, no 5, p. 20-21Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Cellulosa används sedan länge i många produkter. Än så länge gäller det främst inom trävaru-, pappers- och massaindustrin. Men veden innehåller även andra ämnen, som idag mest ses som onödiga restprodukter. Aktuell forskning vid KTH visar att sådana produkter i framtiden kan bli användbara i till exempel förpackningar, läkemedelsindustri och jordbruk.

  • 12.
    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.
    Wood hydrolysates turned valuable2012In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Article in journal (Other academic)
  • 13.
    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)
  • 14.
    Albertsson, Ann-Christine
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Edlund, Ulrica
    KTH, Superseded Departments, Polymer Technology.
    Stridsberg, K.
    Controlled ring-opening polymerization of lactones and lactides2000In: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 157, p. 39-46Article in journal (Refereed)
    Abstract [en]

    1,5-dioxepan-2-one (DXO) is presented as a versatile component in biodegradable polymers for biomedical applications. Copolymerization of DXO and L-lactide yielded a semi-crystalline, yet flexible, material where the extent of crystallinity and erosion characteristics were controlled by an appropriate choice of copolymer composition. Crosslinked PDXO was polymerized as a novel biodegradable elastomer. The degradation behavior of these materials were explored in vitro. Microspheres from poly(DXO-co-L-LA) were prepared and shown to be promising candidates for controlled release. The polymer composition and drug solubility provided effective means of controlling the drug delivery pattern.

  • 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.
    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)
  • 16.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Erlandsson, Bengt
    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.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Molecular weight changes and polymeric matrix changes correlated with the formation of degradation products in biodegraded polyethylene1999In: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 64, p. 91-99Article in journal (Refereed)
    Abstract [en]

    The molecular weight changes in abiotically and biotically degraded LDPE and LDPE modified with starch and/or prooxidant were compared with the formation of degradation products, The samples were thermooxidized for 6 days at 100 degrees C to initiate degradation and then either inoculated with Arthobacter paraffineus or kept sterile. After 3.5 years homologous series of mono- and dicarboxylic acids and ketoacids were identified by GC-MS in abiotic samples, while complete disappearance of these acids was observed in biotic environments. The molecular weights of the biotically aged samples were slightly higher than the molecular weights of the corresponding abiotically aged samples, which is exemplified by the increase in (M) over bar(n) from 5200 g/mol for a sterile sample with the highest amount of prooxidant to 6000 g/mol for the corresponding biodegraded sample. The higher molecular weight in the biotic environment is explained by the assimilation of carboxylic acids and low molecular weight polyethylene chains by microorganisms. Assimilation of the low molecular weight products is further confirmed by the absence of carboxylic acids in the biotic samples. Fewer carbonyls and more double bonds were seen by FTIR in the biodegraded samples, which is in agreement with the biodegradation mechanism of polyethylene.

  • 17.
    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: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 238Article in journal (Other academic)
  • 18.
    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 1064-7546, E-ISSN 1572-8900, 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.

  • 19.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Gröning, Mikael
    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.
    Chromatographic analysis as a tool for predicting material performance2005In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, p. 247-248Article in journal (Other academic)
  • 20.
    Albertsson, Ann-Christine
    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.
    Degradable polymers and their interaction with the environment2007In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 223, p. 566-567Article in journal (Other academic)
  • 21.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Designed to degrade Suitably designed degradable polymers can play a role in reducing plastic waste2017In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 358, no 6365, p. 872-873Article in journal (Refereed)
  • 22.
    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)
  • 23.
    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: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 234Article in journal (Other academic)
  • 24.
    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.

  • 25.
    Albertsson, Ann-Christine
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Olander, Björn
    KTH, Superseded Departments, Polymer Technology.
    Edlund, Ulrica
    KTH, Superseded Departments, Polymer Technology.
    Källrot, Martina
    KTH, Superseded Departments, Polymer Technology.
    Increased biocompatibility by surface modification2004In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 228, p. U508-U508Article in journal (Other (popular science, discussion, etc.))
  • 26.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Srivastava, Rajiv K.
    Recent developments in enzyme-catalyzed ring-opening polymerization2008In: Advanced Drug Delivery Reviews, ISSN 0169-409X, E-ISSN 1872-8294, Vol. 60, no 9, p. 1077-1093Article, review/survey (Refereed)
    Abstract [en]

    An exponential growth has been observed in the last decade where enzymes were used as catalysts for polymerization of different monomers and due to enzyme's origin from natural sources they have been taken as a substitute for the metal-based catalytic systems. Mild polymerization conditions, high enantio- and regio-selectivity and recyclability of enzymes give them an extra edge over the use of organo-metallic catallysts. Though the enzyme-catalyzed polymerizations are environmentally highly advantageous, the high cost, large quantity of enzymes required for polymerization and formation of relatively low molecular weight polymers obstruct their employment in the industry. Due to these reasons, this technique is still at die stage of infancy to generate polymeric materials which can be converted to any useful physical form. In this article enzyme-catalyzed ring-opening polymerization of lactones, lactides, cyclic carbonates and depsipeptides has been reviewed with special focus on the molecular weight of the polymers synthesized hitherto using enzyme catalysis. It is necessary to obtain polymers of sufficient molecular weight from enzyme catalysis to withstand the specific requirements of their end applications if this technique is desired to be escalated to commercial level.

  • 27.
    Albertsson, Ann-Christine
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Varma, I. K.
    Recent developments in ring opening polymerization of lactones for biomedical applications2003In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 4, no 6, p. 1466-1486Article, review/survey (Refereed)
    Abstract [en]

    Aliphatic polyesters prepared by ring-opening polymerization of lactones are now used worldwide as bioresorbabale devices in surgery (orthopaedic devices, sutures, stents, tissue engineering, and adhesion barriers) and in pharmacology (control drug delivery). This review presents the various methods of the synthesis of polyesters and tailoring the properties by proper control of molecular weight, composition, and architecture so as to meet the stringent requirements of devices in the medical field. The effect of structure on properties and degradation has been discussed. The applications of these polymers in the biomedical field are described in detail.

  • 28.
    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)
  • 29.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Voepel, Jens
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Dahlman, Olof
    Soderqvist-Lindblad, Margaretha
    Design of Renewable Hydrogel Release Systems from Fiberboard Mill Wastewater2010In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 11, no 5, p. 1406-1411Article in journal (Refereed)
    Abstract [en]

    A new route for the design of renewable hydrogels is presented. The soluble waste from masonite production was isolated, fractionized, and upgraded. The resulting hemicellulose rich fraction was alkenyl-functionalized and used in the preparation of covalently cross-linked hydrogels capable of sustained release of incorporated agents. Said hydrogels showed a Fickian diffusion-based release of incorporated bovine serum albumin. Also, a method for the coating of seeds with hydrogel was developed. The sustained release of incorporated growth retardant agents from the hydrogel coating on rape seeds was shown to enable the temporary inhibition of germination.

  • 30.
    Andronova, Natalia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Resilient bioresorbable copolymers based on trimethylene carbonate, L-lactide, and 1,5-dioxepan-2-one2006In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 7, no 5, p. 1489-1495Article in journal (Refereed)
    Abstract [en]

    The new combinations of monomers presented in this work were evaluated in order to create an elastic material for potential application in soft tissue engineering. Thermoplastic elastomers (TPE) of trimethylene carbonate (TMC) with L-lactide (LLA) and 1,5-dioxepan-2-one (DXO) have been synthesized using a cyclic five-membered tin alkoxide initiator. The block copolymers were designed in such a way that poly(trimethylene carbonate-co1,5-dioxepan-2-one) formed an amorphous middle block and the poly(L-lactide) (PLLA) formed semicrystalline terminal blocks. The amorphous middle block consisted of relatively randomly distributed TMC and DXO monomer units, and the defined block structure of the PLLA terminal segments was confirmed by C-13 NMR. The properties of the TMC-DXO-LLA copolymers were compared with those of triblock copolymers based either on LLA-TMC or on LLA-DXO. Differential scanning calorimetry and dynamic mechanical analysis data confirmed the micro-phase separation in the copolymers. The mechanical properties of the copolymers were evaluated using tensile testing and cycling loading. All of the copolymers synthesized showed a highly elastic behavior. The properties of copolymers could be tailored by altering the proportions of the different monomers.

  • 31.
    Andronova, Natalia
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Finne, Anna
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Fibrillar structure of resorbable microblock copolymers based on 1,5-dioxepan-2-one and epsilon-caprolactone2003In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, no 15, p. 2412-2423Article in journal (Refereed)
    Abstract [en]

    The copolymerization of 1,5-dioxepan-2-one (DXO) and E-caprolactone, initiated by a five-membered cyclic tin alkoxide initiator, was performed in chloroform at 60 degreesC. Copolymers with different molar ratios of DXO (25, 40, and 60%) were synthesized and characterized. C-13 NMR spectroscopy of the carbonyl region revealed the formation of copolymers with a blocklike structure. Differential scanning calorimetry measurements showed that all the copolymers had a single glass transition between -57 and -49 degreesC and a melting temperature in the range of 30.1-47.7 degreesC, both of which were correlated with the amount of DXO. An increase in the amount of DXO led to an increase in the glass-transition temperature and to a decrease in the melting temperature. Dynamic mechanical thermal analysis measurements confirmed the results of the calorimetric analysis, showing a single sharp drop in the storage modulus in the temperature region corresponding to the glass transition. Tensile testing demonstrated good mechanical properties with a tensile strength of 27-39 MPa and an elongation at break of up to 1400%. The morphology of the copolymers was examined with polarized optical microscopy and atomic force microscopy; the films that crystallized from the melt showed a short fibrillar structure (with a length of 0.05-0.4 mum) in contrast to the untreated solution-cast films. (C) 2003 Wiley Periodicals, Inc.

  • 32.
    Andronova, Natalia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Srivastava, Rajiv
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Potential tissue implants from the networks based on 1,5-dioxepan-2-one and epsilon-caprolactone2005In: Polymer journal, ISSN 0032-3896, E-ISSN 1349-0540, Vol. 46, no 18, p. 6746-6755Article in journal (Refereed)
    Abstract [en]

    The synthesis and characterization of degradable polymeric networks for biomedical applications was performed. Cross-linked films of poly(epsilon-caprolactone) (PCL) and poly(1,5-dioxepan-2-one) (PDXO) having various mole fractions of monomers and different cross-link densities were successfully prepared using 2,2'-bis-(epsilon-caprolactone-4-yl) propane (BCP) as cross-linking agent. Reaction parameters were carefully examined to optimise, the film-formin.,, conditions. Networks obtained were elastomeric materials. easy to cast and remove from the mould. Effect of CL content and cross-link density on the final properties of the polymer network was evaluated. High CL content or degree of cross-linking led to increase in Young's modulus and decrease in elongation at break. An increase in crystalline domains in films having a higher CL content was observed by optical microscopy. A greater thermal stability was observed in films having a high CL content. The hydrophilicity of the materials could be tailored by changing the CL content. The surface of the films became rougher with higher CL content.

  • 33.
    Arias, Veluska
    et al.
    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.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Polylactides with "green" plasticizers: Influence of isomer composition2013In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 130, no 4, p. 2962-2970Article in journal (Refereed)
    Abstract [en]

    Synthesized polylactides (PLA) with different D-isomer contents in the polymer chain were melt-blended with a series of green plasticizers by extrusion. Mechanical and thermal properties as well as the morphology of the plasticized materials were characterized to demonstrate how the combination of PLA with different D-contents and plasticizer controls the material properties. After addition of acetyl tributyl citrate (ATC), the elongation at break for PLA with a low D-isomer content was twice as high as that for PLAs with high D-isomer contents. Similar variations in the plasticization effect on the PLAs were also observed with the other plasticizers used, glyceryl triacetate (GTA), glycerol trihexanoate (GTH) and polyethylene glycol (PEG). In order to continue with the development of renewable polymers in packaging applications, the interrelation between a plasticizer and a specific polymer needs to be understood.

  • 34.
    Arias, Veluska
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Tailoring the hydrolytic endurance of Poly(L-lactide)-based products2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 248Article in journal (Other academic)
  • 35.
    Arias, Veluska
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Tuning the Degradation Profiles of Poly(L-lactide)-Based Materials through Miscibility2014In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 15, no 1, p. 391-402Article in journal (Refereed)
    Abstract [en]

    The effective use of biodegradable polymers relies on the ability to control the onset of and time needed for degradation. Preferably, the material properties should be retained throughout the intended time frame, and the material should degrade in a rapid and controlled manner afterward. The degradation profiles of polyester materials were controlled through their miscibility. Systems composed of PLLA blended with poly[(R,S)-3-hydroxybutyrate] (a-PHB) and polypropylene adipate (PPA) with various molar masses were prepared through extrusion. Three different systems were used: miscible (PLLA/a-PHB5 and PLLA/a-PHB20), partially miscible (PLLA/PPA5/comp and PLLA/PPA20/comp), and immiscible (PLLA/PPA5 and PLLA/PPA20) blends. These blends and their respective homopolymers were hydrolytically degraded in water at 37 degrees C for up to I year. The blends exhibited entirely different degradation profiles but showed no diversity between the total degradation times of the materials. PLLA presented a two-stage degradation profile with a rapid decrease in molar mass during the early stages of degradation, similar to the profile of PLLA/a-PHB5. PLLA/a-PHB20 presented a single, constant linear degradation profile. PLLA/PPA5 and PLLA/PPA20 showed completely opposing degradation profiles relative to PLLA, exhibiting a slow initial phase and a rapid decrease after a prolonged degradation time. PLLA/PPA5/comp and PLLA/PPA20/comp had degradation profiles between those of the miscible and the immiscible blends. The molar masses of the materials were approximately the same after 1 year of degradation despite their different profiles. The blend composition and topographical images captured at the last degradation time point demonstrate that the blending component was not leached out during the period of study. The hydrolytic stability of degradable polyester materials can be tailored to obtain different and predetermined degradation profiles for future applications.

  • 36.
    Arias, Veluska
    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.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nano-Stereocomplexation of Polylactide (PLA) Spheres by Spray Droplet Atomization2014In: Macromolecular rapid communications, ISSN 1022-1336, E-ISSN 1521-3927, Vol. 35, no 22, p. 1949-1953Article in journal (Refereed)
    Abstract [en]

    A direct, efficient, and scalable method to prepare stereocomplexed polylactide (PLA)-based nanoparticles (NPs) is achieved. By an appropriate combination of fabrication parameters, NPs with controlled shape and crystalline morphology are obtained and even pure PLA stereocomplexes (PLASC) are successfully prepared using the spray-drying technology. The formed particles of varying D- and L-LA content have an average size of approximate to 400 nm, where the smallest size is obtained for PLA50, which has an equimolar composition of PLLA and PDLA in solution. Raman spectra of the particles show the typical shifts for PLASC in PLA50, and thermal analysis indicates the presence of pure stereocomplexation, with only one melting peak at 226 degrees C. Topographic images of the particles exhibit a single phase with different surface roughness in correlation with the thermal analysis. A high yield of spherically shaped particles is obtained. The results clearly provide a proficient method for achieving PLASC NPs that are expected to function as renewable materials in PLA-based nanocomposites and potentially as more stable drug delivery carriers.

  • 37.
    Arias, Veluska
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Homocomposites of Polylactide (PLA) with Induced Interfacial Stereocomplex Crystallites2015In: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 3, no 9, p. 2220-2231Article in journal (Refereed)
    Abstract [en]

    The demand for “green” degradable composite materials increases with growing environmental awareness. The key challenge is achieving the preferred physical properties and maintaining their eco-attributes in terms of the degradability of the matrix and the filler. Herein, we have designed a series of “green” homocomposites materials based purely on polylactide (PLA) polymers with different structures. Film-extruded homocomposites were prepared by melt-blending PLA matrixes (which had different degrees of crystallinity) with PLLA and PLA stereocomplex (SC) particles. The PLLA and SC particles were spherical and with 300–500 nm size. Interfacial crystalline structures in the form of stereocomplexes were obtained for certain particulate-homocomposite formulations. These SC crystallites were found at the particle/matrix interface when adding PLLA particles to a PLA matrix with d-lactide units, as confirmed by XRD and DSC data analyses. For all homocomposites, the PLLA and SC particles acted as nucleating agents and enhanced the crystallization of the PLA matrixes. The SC particles were more rigid and had a higher Young’s modulus compared with the PLLA particles. The mechanical properties of the homocomposites varied with particle size, rigidity, and the interfacial adhesion between the particles and the matrix. An improved tensile strength in the homocomposites was achieved from the interfacial stereocomplex formation. Hereafter, homocomposites with tunable crystalline arrangements and subsequently physical properties, are promising alternatives in strive for eco-composites and by this, creating materials that are completely degradable and sustainable.

  • 38.
    Arias, Veluska
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Odent, Jeremy
    Raquez, Jean-Marie
    Dubois, Philippe
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Toward "Green" Hybrid Materials: Core-Shell Particles with Enhanced Impact Energy Absorbing Ability2016In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 4, no 7, p. 3757-3765Article in journal (Refereed)
    Abstract [en]

    Restrained properties of "green" degradable products drive the creation of materials with innovative structures and retained eco-attributes. Herein, we introduce the creation of impact modifiers in the form of core-shell (CS) particles toward the creation of "green" composite materials. Particles with CS structure constituted of PLA stereocomplex (PLASC) and a rubbery phase of poly(epsilon-caprolactone-co-D,L-lactide) (P[CL-co-LA]) were successfully achieved by spray droplet atomization. A synergistic association of the soft P[CL-co-LA] and hard PLASC domains in the core-shell structure induced unique thermo-mechanical effects on the PLA-based composites. The core-shell particles enhanced the crystallization of PLA matrices by acting as nucleating agents. The core-shell particles functioned efficiently as impact modifiers with minimal effect on the composites stiffness and strength. These findings provide a new platform for scalable design of polymeric-based structures to be used in the creation of advanced degradable materials.

  • 39.
    Arias, Veluska
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Olsén, Peter
    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.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Forecasting linear aliphatic copolyester degradation through modular block design2016In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 130, p. 58-67Article in journal (Refereed)
    Abstract [en]

    The development of efficient methods to predict the degradation of renewable polymeric materials is continuously sought in the field of polymer science. Herein, we present a modular build-up approach to create polyester-based materials with forecasted degradation rates based on the hydrolysis of the constituent polymer blocks. This involved the strategic combination of critical factors affecting polyester hydrolysis, i.e. hydrophobicity and degree of crystallinity. The starting point of this method was a toolbox of polymers with different hydrophobicities and degrees of crystallinity, as well as an understanding of their inherent differences in hydrolysis rate. Knowledge of the hydrolysis of each polymer block module enabled the prediction of the overall degradation behavior of the constructed copolymers. Taking advantage of the primary factors that affect polymer degradation, block copolymers could be independently designed to incorporate soft or rigid and faster or slower degradation properties. This approach generated a shift for how molecular design can be used to predict the degradation behavior of intended materials for different applications.

  • 40.
    Arias, Veluska
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Olsén, Peter
    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.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Selective degradation in aliphatic block copolyesters by controlling the heterogeneity of the amorphous phase2015In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 6, no 17, p. 3271-3282Article in journal (Refereed)
    Abstract [en]

    Controlling the course of the degradation of aliphatic polyesters is a key question when designing new degradable materials. It is shown herein that it is possible to predetermine the degradation path of aliphatic block copolyesters by controlling the heterogeneity of the amorphous phase, which in turn regulates the availability of the hydrolyzable groups in the polyester backbone. To demonstrate these processes, we synthesized a set of degradable materials based on poly(l-lactide) (PLLA), poly(ε-decalactone) (PεDL) and poly(ε-caprolactone) (PCL) with varying compositions. The materials were subjected to hydrolysis for a six months period. The materials composed of PLLA and PεDL exhibited a heterogeneous amorphous phase, whereas the materials composed of PCL and PεDL presented a more homogeneous phase. The kinetics of the degradation indicated that the slowest degradation rate was observed for the more homogeneous compositions. The degradation path of the heterogeneous amorphous phase materials was driven by a random chain scission process, whereas the more homogeneous composition presented a degradation path driven by a more selective chain scission. The confinement of the amorphous phase by the more hydrolytically stable PεDL permitted a selective degradation of the available hydrolyzable groups. The random and more selective chain scission processes were further verified by using previously determined molecular modeling based on Monte Carlo procedures. Topographical images and thermal analyses of the materials under different degradation periods correlated with the proposed degradation paths. Detailed insights and the ability to predetermine the degradation pathways of aliphatic polyesters will continue to expand the great potential of renewable materials and their use in specific applications for a future sustainable society.

  • 41. Brunius, C. F.
    et al.
    Edlund, Ulrica
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Synthesis and in vitro degradation of poly(N-vinyl-2-pyrrolidone)-based graft copolymers for biomedical applications2002In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 40, no 21, p. 3652-3661Article in journal (Refereed)
    Abstract [en]

    This work is devoted to the design of a novel family of hydrosoluble biomaterials: poly(N-vinyl-2-pyrrolidone) (PVP)-based graft copolymers. A synthesis route has been elaborated in which omega-functionalized PVP is prepared via chain-transfer radical polymerization, end-group modified, and subsequently grafted onto a polyhydroxylated backbone, typically dextran or poly(vinyl alcohol). The resulting graft copolymer biomaterials are designed for use in various biomedical applications, particularly as materials with a stronger potential for plasma expansion than already existing products have. The graft copolymers are potentially degradable because the PVP grafts are connected to the polyol backbone via a hydrolytically labile carbonate or ester linkage. The degradation of the graft copolymers was performed in vitro over a period of 6 weeks.

  • 42.
    Burman, Lina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Chromatographic Fingerprinting - a Tool for Classification and for Predicting the Degradation State of Degradable Polyethylene2005In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 89, no 1, p. 50-63Article in journal (Refereed)
    Abstract [en]

    The number of degradable polyethylene films on the market is increasing. These degradable films show different degradation behaviour depending on the pro-oxidant system incorporated in them. The degradation of the films gives rise to complex collections of degradation products. The key question in this work was to classify the types of pro-oxidant systems in degradable polyethylene films and the state of degradation of the films. The classification was performed with chromatographic fingerprints of carboxylic acids, the most abundant type of degradation product. The acids were extracted from films oxidised at 80 ° C and were thereafter methylated and analysed by GC-MS. Classification and prediction models were obtained by Multivariate Data Analysis. The diacids were grouped according to both the type of pro-oxidant system and the state of degradation. This showed that both the type of pro-oxidant system and the state of degradation are predictable from the diacid fingerprints. The monoacids were shown to be useful for classifying materials from their initial compositions of stearates but not for predicting the degradation state. The goal was also to see how changes in activation energies for hydroperoxides, noticed earlier with chemiluminescence, were reflected in the degradation mechanisms. The observed increase in chemiluminescence peak temperature of the polyoctylene-containing film was related to the initial degradation of the polyoctylene.

  • 43.
    Burman, Lina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Evaluation of Long-Term Performance of Antioxidants Using Prooxidants instead of Thermal Acceleration2005In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 43, no 19, p. 4537-4546Article in journal (Refereed)
    Abstract [en]

    Evaluation of stabilization efficiencies of different antioxidants in polymers at low temperature and relatively short time was performed using incorporation of a prooxidant for catalytic oxidation. Comparisons were made between polypropylene films stabilized with primary antioxidants (Irganox 1076, Irganox 1010, and α-tocopherol), with or without the prooxidant manganese stearate at different temperatures. A faster degradation was obtained in the presence of a prooxidant than without it. The relative efficiency of the antioxidants at prooxidant acceleration correlated better to low temperature long-term test than at the thermal acceleration. The results were affected by initial differences in the amounts of the antioxidants present after the processing of the films. These differences were corrected for by a recalculation using microwave-assisted extraction (MAE) and high performance liquid chromatography analysis from the exponential decrease in the amount of antioxidant in the films. The fastest comparison of the antioxidants efficiency was obtained from oxidation induction times, using total luminescence intensity measurements, but reliable results could also be obtained from the time to apparent failure.

  • 44.
    Burman, Lina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Indicator products and chromatographic fingerprinting: New tools for degradation state and lifetime estimation2008In: CHROMATOGRAPHY FOR SUSTAINABLE POLYMERIC MATERIALS: RENEWABLE, DEGRADABLE AND RECYCLABLE, Berlin: Springer Verlag , 2008, Vol. 211, p. 1-22Chapter in book (Refereed)
    Abstract [en]

    The demands on polymeric products are growing both with respect to their function and purity. There is a need for new high-throughput characterisation tools for rapid quality control and evaluation of materials. Precise control over degradation rate and service-life are also prerequisites for successful use of degradable polymers in an increasing number of applications. The chromatographic fingerprinting and indicator product concepts, presented in the current paper, are novel and attractive alternatives for rapid evaluation of the product quality, degradability, durability and service-life. The sensitivity of these techniques allows for detection of small initial changes in the materials and signs of early degradation. The possible applications include evaluation of different pro-oxidants or antioxidants, optimisation of processing parameters, evaluation of long-term properties or storage stability and lifetime prediction. The same principal could also be applied to process control and monitoring, acceptance or rejection of raw materials, intermediate and final products. The usefulness of indicator products and chromatographic fingerprinting is shown for estimation of the degradation state of degradable polyethylene. in addition, chromatographic fingerprinting together with multivariate data analysis is utilised to classify degradable polyethylene materials based on their incorporated pro-oxidant systems.

  • 45.
    Burman, Lina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    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.
    Solid-Phase Microextraction for Qualitative and Quantitative Determination of Migrated Degradation Products of Antioxidants in an Organic Aqueous Solution2005In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1080, no 2, p. 107-116Article in journal (Refereed)
    Abstract [en]

     Low molecular weight aromatic substances may migrate out from plastic packaging to their contents, especially if they consist of organic aqueous solutions or oils. It is, therefore, extremely important to be able to identify and quantify any migrated substances in such solutions, even at very low concentrations. We have in this work investigated and evaluated the use of solid-phase microextraction for the specific task of extraction from an organic aqueous solution such as a simulated pharmaceutical solution consisting of 10 vol.% ethanol in water. The goal was furthermore to investigate the possibility of simultaneously identifying and quantifying the substances in spite of differences in their chemical structures. Methods were developed and evaluated for extraction both with direct sampling and with headspace sampling. Difficulties appeared due to the ethanol in the solution and the minute amounts of substances present. We have shown that a simultaneous quantification of migrated low molecular weight degradation products of antioxidants using only one fibre is possible if the extraction method and temperature are adjusted in relation to the concentration levels of the analytes. Comparions were made with solid-phase extraction.

  • 46.
    Dahlman, Olof
    et al.
    Innventia AB.
    Söderqvist Lindblad, Margaretha
    Södra Cell AB.
    Parkaas, Jim
    Södra Cell AB.
    Albertsson, Ann-Christine
    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.
    Utilization of a wood hydrolysate2007Patent (Other (popular science, discussion, etc.))
  • 47. Danmark, Staffan
    et al.
    Finne Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wendel, Mikael
    Arvidson, Kristina
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Mustafa, Kamal
    Osteogenic Differentiation by Rat Bone Marrow Stromal Cells on Customized Biodegradable Polymer Scaffolds2010In: Journal of bioactive and compatible polymers (Print), ISSN 0883-9115, E-ISSN 1530-8030, Vol. 25, no 2, p. 207-223Article in journal (Refereed)
    Abstract [en]

    In this report, poly(L-lactide-co-epsilon-caprolactone), poly(LLA-co-CL) and poly(L-lactide-co-1,5-dioxepan-2-one), poly(LLA-co-DXO) were evaluated and compared for potential use in bone tissue engineering constructs together with bone marrow stromal cells (BMSC). The copolymers were tailored to reduce the level of harmful tin residuals in the scaffolding. BMSC isolated from Sprague-Dawley rats were seeded onto the scaffolds and cultured in vitro for up to 21 days. Cell spreading and proliferation was analyzed after 72 h by scanning electron microscopy and thiazolyl blue tetrazolium bromide (MTT) conversion assay. Osteogenic differentiation of BMSC was evaluated by real-time PCR after 14 and 21 days of culture. Hydrophilicity was significantly different between poly(LLA-co-CL) and poly(LLA-co-DXO) with the latter being more hydrophilic. After 72 h, both scaffolds supported increased cell proliferation and the mRNA expression of osteocalcin and osteopontin was significantly increased after 21 days. Further investigation of these constructs, with lower levels of tin residuals, are being pursued.

  • 48. David, Geta
    et al.
    Simionescu, Bogdan C.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Rapid deswelling response of poly(N-isopropylacrylamide)/poly(2-alkyl-2-oxazoline)/poly(2-hydroxyethy l methacrylate) hydrogels2008In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 9, no 6, p. 1678-1683Article in journal (Refereed)
    Abstract [en]

    Ternary poly(N-isopropylacrylamide)/poly(2-alkyl-2-oxazoline)/poly(2-hydroxyethy l methacrylate) (PNIPAAm/PROZO/PHEMA) hydrogels were prepared by the free-radical copolymerization of N-isopropylacrylamide (NIPAAm), 2-hydroxyethyl methacrylate (HEMA), and poly(2-alkyl-2-oxazoline) (PROZO) multifunctional macromonomers. The resulting polymeric materials were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), as well as by equilibrium swelling experiments. All synthesized hydrogels display temperature sensitivity in the 28-38 degrees C range. A high rate of response was registered as compared to that of materials based only on PNIPAAm. The swelling-deswelling peculiar behavior was related to the chemical composition (hydrophile/hydrophobe balance), the length of the inserted PROZO sequence, and inner morphology, an aspect which points on its possible control by synthesis. It was evidenced that the architecture of the resulting porous materials has a high order degree, emerging from the self-assembling of the microgel particles, which provided numerous, nearly uniform, large water release channels.

  • 49.
    Dånmark, Staffan
    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.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Patarroyo, Manuel
    Institutionen for Odontologi, Karolinska Institute.
    Mustafa, Kamal
    Insititutt for klinisk Odontologi, Medicinska och Odontologiska Fakulteten, Universitetet i Bergen, Norge.
    Integrin-mediated adhesion of human mesenchymal stem cells to extracellular matrix proteins adsorbed to polymer surfaces2012In: Biomedical Materials, ISSN 1748-6041, E-ISSN 1748-605X, Vol. 7, no 3, p. 035011-Article in journal (Refereed)
    Abstract [en]

    In vitro, degradable aliphatic polyesters are widely used as cell carriers for bone tissue engineering, despite their lack of biological cues. Their biological active surface is rather determined by an adsorbed layer of proteins from the surrounding media. Initial cell fate, including adhesion and proliferation, which are key properties for efficient cell carriers, is determined by the adsorbed layer of proteins. Herein we have investigated the ability of human bone marrow derived stem cells (hBMSC) to adhere to extracellular matrix (ECM) proteins, including fibronectin and vitronectin which are present in plasma and serum. hBMSC expressed integrins for collagens, laminins, fibronectin and vitronectin. Accordingly, hBMSC strongly adhered to these purified ECM proteins by using the corresponding integrins. Although purified fibronectin and vitronectin adsorbed to aliphatic polyesters to a lower extent than to cell culture polystyrene, these low levels were sufficient to mediate adhesion of hBMSC. It was found that plasma- and serum-coated polystyrene adsorbed significant levels of both fibronectin and vitronectin, and fibronectin was identified as the major adhesive component of plasma for hBMSC; however, aliphatic polyesters adsorbed minimal levels of fibronectin under similar conditions resulting in impaired cell adhesion. Altogether, the results suggest that the efficiency of aliphatic polyesters cell carriers could be improved by increasing their ability to adsorb fibronectin.

  • 50.
    Dånmark, Staffan
    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.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Mustafa, Kamal
    Insititutt for klinisk Odontologi, Medicinska och Odontologiska Fakulteten, Universitetet i Bergen, Norge.
    Enhanced Osteoconductivity of Degradable co-Polyester Scaffolds through Covalent Immobilization of BMP-2Manuscript (preprint) (Other academic)
123456 1 - 50 of 299
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