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  • 301.
    Gustafsson, Emil
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Hedberg, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Larsson, Per A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Vibrational sum frequency spectroscopy on polyelectrolyte multilayers – effect of molecular surface structure on macroscopic wetting propertiesManuscript (preprint) (Other academic)
  • 302.
    Gustafsson, Emil
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Pelton, Robert
    McMaster University.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Polyelectrolyte Entanglement across Interfaces and Wet Adhesion- Influence of Polyvinylamine on Wet Adhesion between Cellulose Model Surfaces Modified with CarboxymethylcelluloseManuscript (preprint) (Other academic)
  • 303. Gällstedt, Mikael
    et al.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Türe, Hasan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Production, Chemistry and Properties of Proteins2011In: Biopolymers: New Materials for Sustainable Films and Coatings / [ed] David Plackett, Chichester: John Wiley & Sons, 2011, p. 107-132Chapter in book (Other academic)
  • 304.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Aliphatic polyesters: Abiotic and biotic degradation and degradation products2002In: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 157, p. 113-138Article, review/survey (Refereed)
    Abstract [en]

    This paper reviews the degradation behavior of aliphatic polyesters of current interest, including polylactide, polycaprolactone, poly(3-hydroxybutyrate) and their copolymers. Special focus is given to degradation products formed in different abiotic and biotic environments. The influence of processing and processing additives on the properties and degradation behavior is also briefly discussed.

  • 305.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Multiple headspace single-drop micro-extraction for quantitative determination of lactide in thermally-oxidized polylactide2010In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 95, no 3, p. 270-273Article in journal (Refereed)
    Abstract [en]

    Single-drop micro-extraction (SDME), an emerging micro-extraction technique, was combined with multiple headspace (MHS) extraction to allow quantitative determination of lactide in thermally-oxidized polylactide Different solvents, drop sizes and extraction times were tested to obtain best extraction efficiency and the method was further developed to obtain a linear regression plot for the Multiple extractions. The combination of SDME and MHS extraction offered several advantages over traditional liquid-solid and headspace extraction techniques No concentration step was needed and loss of volatiles was prevented as the ageing and extraction were performed in a closed system Matrix effects, that disturb the quantitation of analytes in solid samples, were removed by the multiple headspace extraction.

  • 306.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    New PVC materials for medical applications - the release profile of PVC/polycaprolactone-polycarbonate aged in aqueous environments2003In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 80, no 3, p. 451-458Article in journal (Refereed)
    Abstract [en]

    Medical grade PVC plasticised with polycaprolactone-polycarbonate (PCL-PC) was subjected to aqueous environments at different temperatures. The release profile during ageing was determined by solid phase microextraction (SPME) and GC-MS. At the same time changes in the surface composition due to, for example, migration of PCL-PC from the blend were followed by FTIR. Almost no changes in the material or its surface composition were observed during 98 days at 37 degreesC in water or phosphate buffer. Only trace amount of 6-hydroxyhexanoic acid the final hydrolysis product of PCL-PC was detected in the GC-MS chromatograms and the weight loss was negligible. Even when the ageing temperature was raised to 70 degreesC only minor increase in the amount of 6-hydroxyhexanoic acid was observed and the weight loss after 98 days was under 1%. Changes in the FTIR spectra indicating migration of PCL-PC towards the surface of the PVC/PCL-PC tubing were observed first after 70 days at 70 degreesC. Large increase in the hydrolysis rate of PCL-PC and almost complete depletion of PCL-PC from the blend was observed when the ageing temperature was raised to 100 degreesC.

  • 307.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Qualitative and quantitative solid-phase microextraction gas chromatographic-mass spectrometric determination of the low-molecular-mass compounds released from poly(vinyl chloride)/polycaprolactone-polycarbonate during ageing2003In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1010, no 1, p. 9-16Article in journal (Refereed)
    Abstract [en]

    A solid-phase microextraction (SPME) method was developed to quantitatively determine the amount of 6-hydroxyhexanoic acid in aqueous solutions. The SPME method in combination with GC-MS was then applied to identify and quantify the low-molecular-mass compounds migrating from a new poly(vinyl chloride) (PVC) material, PVC/polycaprolactone-polycarbonate (PCL-PC) during ageing in water. It was shown that only a small amount of 6-hydroxyhexanoic acid, the final hydrolysis product of PCL-PC, migrated from the blend during ageing at 37 and 70 degreesC. If, however, the temperature was raised to 100 degreesC rapid hydrolysis of PCL-PC resulted. In addition to 6-hydroxyhexanoic acid, 6-hydroxyhexanoic acid dimer, caprolactone, different carboxylic acids, acetophenone and phenol were identified. SPME-GC-MS was also applied to monitor the low-molecular-mass compounds migrating from the PVC/PCL-PC blend during thermo-oxidation.

  • 308.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adamus, Grazyna
    Centre of Polymer and Carbon Materials, Polish Academy of Sciences.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kowalczuk, Marek
    Centre of Polymer and Carbon Materials, Polish Academy of Sciences.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    ESI-MS reveals the influence of hydrophilicity and architecture on the water-soluble degradation product patterns of biodegradable homo- and copolyesters of 1,5-dioxepan-2-one and epsilon-caprolactone2008In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 41, no 10, p. 3547-3554Article in journal (Refereed)
    Abstract [en]

    The hydrolytic degradation process and degradation product patterns of biodegradable homo- and copolyesters of 1,5-dioxepan-2-one (DXO) and epsilon-caprolactone (CL) were monitored by electrospray ionization mass spectrometry (ESI-MS). The degradation product patterns were compared to mass loss, molecular weight changes, copolymer composition, and pH changes after various hydrolysis times. Water-soluble oligomers up to heptadecamer were identified after hydrolysis of hydrophilic PDXO, while only oligomers up to hexamer were detected after hydrolysis of the more hydrophobic PCL. The product pattern of DXO-CL-DXO triblock copolymer mainly consisted of DXO-based oligomers, whereas the CL/DXO multiblock copolymer degradation product pattern contained DXO and CL oligomers as well as oligomers containing both DXO and CL units. The DXO-rich oligomers, however, dominated the product patterns. ESI-MS gave valuable insights into the hydrolysis process of hydrophobic and hydrophilic polyesters and showed that hydrophilicity of the polymer as well as copolymer architecture both greatly influenced the water-soluble degradation product patterns.

  • 309.
    Hakkarainen, Minna
    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.
    Degradation products of aliphatic and aliphatic-aromatic polyesters2008In: Chromatography For Sustainable Polymeric Materials: Renewable, Degradable And Recyclable, BERLIN: SPRINGER-VERLAG , 2008, Vol. 211, p. 85-116Chapter in book (Refereed)
    Abstract [en]

    Analysis of degradation products needs to be included in degradability testing to ensure the environmental adaptability of degradable polymers. Identification of breakdown products from environmental degradation is important for understanding the degradation process, environmental interaction and impact of degradable polymers. with regard to degradability aliphatic polyesters are a particularly interesting group of polymers. They are susceptible to hydrolysis and biological attack due to the ester groups in the main chain. This paper summarizes the work done on the chromatographic analysis of degradation products from the most common aliphatic and aliphatic-aromatic polyesters under different abiotic and biotic conditions including simulated, accelerated and real environmental conditions.

  • 310.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Environmental degradation of polyethylene2004In: LONG-TERM PROPERTIES OF POLYOLEFINS, Berlin, 2004, Vol. 169, p. 177-199Chapter in book (Refereed)
    Abstract [en]

    The environmental degradation of polyethylene proceeds by synergistic action of photo- and thermo-oxidative degradation and biological activity. Since biodegradation of commercial high molecular weight polyethylene proceeds slowly, abiotic oxidation is the initial and rate-determining step. Enhanced environmentally degradable polyethylene is prepared by blending with biodegradable additives or photo-initiators or by copolymerisation. One of the key questions for successful development and use of environmentally degradable polymers is to understand the interaction between degradation products and nature. Polymer fragments and degradation products should be environmentally assimilable and should not accumulate or negatively affect the environment. Determination of abiotic and biotic oxidation products is an important step towards establishing the environmental degradation mechanism and environmental impact of the material. More than 200 different degradation products including alkanes, alkenes, ketones, aldehydes, alcohols, carboxylic acid, keto-acids, dicarboxylic acids, lactones and esters have been identified in thermo- and photo-oxidised polyethylene. In biotic environment these abiotic oxidation products and oxidised low molecular weight polymer can be assimilated by microorganisms. In future we will probably see a development of new polyethylenes with tailor-made structures specially designed for environmental degradation through different pathways. Paralleled with the development of these new materials we need to obtain better understanding of the environmental impact of degradable polymers and the interactions between nature and degradation products in a dynamic system.

  • 311.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Heterogeneous biodegradation of polycaprolactone - Low molecular weight products and surface changes2002In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 203, no 11-okt, p. 1357-1363Article in journal (Refereed)
    Abstract [en]

    Gas chromatography-mass spectrometry (GC-MS) analysis showed that caprolactone, 6-hydroxyhexanoic acid, cyclic dimer and cyclic trimer were rapidly assimilated from the surface of polycaprolactone (PCL) films aged in mineral medium inoculated with a mixed culture of compost microorganisms. The degradation in biotic medium proceeded heterogeneously and scanning electron micrographs revealed the formation of parallel grooves, spherical and non-spherical holes in the films. The parallel grooves seen in the scanning electron micrographs after 14 d suggest that the degradation starts preferentially at the amorphous regions. At longer time scales, even the crystalline regions are degraded producing large spherical and non-spherical holes. Comparison of the degradation of melt-pressed and film-blown films made from the same PCL granules in different biotic and abiotic environments showed that both the type of microorganism used and the initial morphology of the films influence the surface erosion pattern and biodegradation mechanism. Rapid degradation and molecular weight decrease required the combined effect of temperature and microorganisms obtained during a biodegradation process, such as composting.

  • 312.
    Hakkarainen, Minna
    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.
    Indicator products: A new tool for lifetime prediction of polymeric materials2005In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 6, no 2, p. 775-779Article in journal (Refereed)
    Abstract [en]

    The possible correlation between the degree of degradation in the polymer matrix and the release of indicator products was investigated. The degree of degradation was measured by following the molar mass changes by size exclusion chromatography, while indicator products were analyzed by gas chromatography -mass spectrometry. The degree of degradation in polyethylene and polyethylene vinyl acetate matrix after thermooxidation was found to be in correlation with the amount of dicarboxylic acids and lactones formed during aging, while the degree of degradation in photooxidized polyethylene could be predicted from the amount of dicarboxylic acids. The relative amount of lactones compared to the relative amount of dicarboxylic acids increased if the oxidation temperature was increased. However, the total amount of indicator products was in correlation with the remaining number average molar mass and the number of chain scissions caused by oxidation. The amount of butanedioic acid and butyrolactone correlated well with the total amount of dicarboxylic acids and lactones, respectively. Thus, instead of the whole compound classes, butanedioic acid or butyrolactone alone could be used as indicators of oxidation. The detected correlation offers a novel tool for making lifetime predictions and studying the long-term properties of polymeric materials.

  • 313.
    Hakkarainen, Minna
    et al.
    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.
    Kalrsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Weight losses and molecular weight changes correlated with the evolution of hydroxyacids in simulated in vivo degradation of homo-and copolymers of PLA and PGA1996In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 52, p. 283-291Article in journal (Refereed)
  • 314.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments, Polymer Technology.
    Migration and emission of plasticizer and its degradation products during thermal aging of nitrite rubber2003In: IJPAC. International journal of polymer analysis and characterization, ISSN 1023-666X, E-ISSN 1563-5341, Vol. 8, no 4, p. 279-293Article in journal (Refereed)
    Abstract [en]

    The behavior of nitrile rubber during long-term thermal aging was evaluated by following the migration of low-molecular-weight additives and additive degradation products from the material. Headspace-GC-MS analysis showed that at 60degreesC the number of low-molecular-weight compounds released was rather low, but a significant increase in the number and amount of products was observed when the temperature was raised from 60degrees to 80degreesC, e.g., several degradation products of tris(2-butoxyethyl)phosphate plasticizer including 2-butoxyethanol and 1-butanol were identified. Oxidation of the plasticizer was also seen in the FTIR spectra. The color of the material changed from light brown to almost black during the aging.

  • 315.
    Hakkarainen, Minna
    et al.
    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.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Solid phase microextraction (SPME) as an effective means to isolate degradation products in polymers1997In: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 5, p. 67-73Article in journal (Refereed)
    Abstract [en]

    A new sample preparation technique, solid phase microextraction (SPME), was compared with direct headspace-GC-MS with respect to the type and amount of identified compounds. Three types of LDPE films containing photosensitising additives according to the Scott-Gilead patents and pure LDPE were used as model substances. The polyethylene films were thermally aged at 80 degrees C after the induction period was surpassed by subjecting the materials to 100 h of UV radiation. The new SPME method was developed using nonpolar poly(dimethylsiloxane) and polar carbowax fibers to extract the low molecular weight products formed in the polyethylene films during aging. Many more products were identified after SPME followed by CC-MS than after direct headspace-GC-MS of the samples. The SPME method allowed the identification of homologous series of carboxylic acids, ketones, and furanones, while direct headspace-GC-MS identified only a few carboxylic acids (C1-C6) and small amounts of some ketones and furanones. In general, SPME was more effective in extracting less volatile products, and in particular, the polar carbowax fiber identified also C7-C12 carboxylic acids and 4-oxopentanoic acid. By SEC and FTIR we confirmed that the number and amount of former degradation products correlated well with the decrease in molecular weights and the amount of formed carbonyl compounds.

  • 316.
    Hakkarainen, Minna
    et al.
    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.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Solid-phase extraction and subsequent gas-chromatography-mass spectrometry analysis for identification of complex mixtures of degradation products in starch-based polymers1996In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 741, p. 251-263Article in journal (Refereed)
  • 317.
    Hakkarainen, Minna
    et al.
    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.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Susceptibility of starch-filled and starch-based LDPE to oxygen in water and air1997In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 66, p. 959-967Article in journal (Refereed)
  • 318.
    Hakkarainen, Minna
    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.
    Update on polylactide based materials2011 (ed. 1)Book (Other academic)
    Abstract [en]

    Today both scientists and industry are working to develop more environmentally friendly processes and materials. One of the most current topics is the development of energy and materials from renewable resources. There are fascinating developments in this area and advanced designed products can today be formed in an environmentally friendly way. Polylactide based materials are among the most promising synthetic renewable resource based materials. There is currently extensive research going on to develop polylactide based materials for different applications. These developments include both the use of new resources, development of more effective and environmentally friendly processes as well as modification and tailoring of material properties and degradability to broaden the application range.

    This book discusses recent developments in polylactide based materials including the whole spectra from different material modifications, applications and properties to new advanced synthesis procedures. When it comes to degradable materials, an important aspect is also the influence of different modifications on material properties, degradability and degradation products. The different chapters present new emerging processes and synthetic techniques as well as different material modifications obtained by copolymerization or blending with degradable or inert, natural or synthetic polymers. In addition advancements and developments in polylactide stereocomplexes, nanocomposites and biocomposites are presented. The book is of interest both from the basic and applied science point of view as it presents the latest trends and demonstrates the versatility and great potential of polylactide based materials. Hopefully the book can inspire the reader to further develop synthesis procedures or new ways to modify polylactide materials to broaden the properties to suit new applications.

  • 319.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Gröning, M.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Solid-phase microextraction (SPME) in polymer characterization - Long-term properties and quality control of polymeric materials2003In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 89, no 3, p. 867-873Article in journal (Refereed)
    Abstract [en]

    Solid-phase microextraction (SPME) in combination with GG-MS was applied to quality control polyamide 6.6 collected for recycling and to study the long-term properties and degadation of nitrile rubber, polyethylene, and polyamide 6.6. The migration of plasticizer and other additives reduces the service-life and changes the properties of the material. It is also a possible health hazard, for example, legislation against the use of brominated flame retardants in plastic materials, is under discussion, and fast and reliable methods are required to detect such compounds in plastic materials collected for recycling. SPME rapidly and effectively extracted several brominated compounds from in-plant collected polyamide 6.6. Migration of tris(2-butoxy-ethyl)phosphate plasticizer and its degradation products from nitrile rubber during long-term thermal ageing at 60 and 80degreesC was shown by SPME-GC-MS, while the plasticizer was not volatile enough to be detected by traditional HS-GC-MS. In accordance the number of degradation products extracted from thermo-oxidized PE by HS-SPME was three times larger than the number detected after HS-GC-MS analysis. SPME-GC-MS could also detect early signs of degradation in thermo-oxidized virgin and in-plant recycled polyamide 6.6 before any signs of degradation were observed by, for example, tensile testing or FTIR.

  • 320.
    Hakkarainen, Minna
    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.
    Tuning the release rate of acidic degradation products through macromolecular design of caprolactone-based copolymers2007In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 129, no 19, p. 6308-6312Article in journal (Refereed)
    Abstract [en]

    Macromolecular engineering is presented as a tool to control the degradation rate and release rate of acidic degradation products from biomedical polyester ethers. Three different caprolactone/1,5-dioxepan-2-one (CL/DXO) copolymers were synthesized: DXO/CL/DXO triblock, CL/DXO multiblock, and random cross-linked CL/DXO copolymer. The relation of CL and DXO units in all three copolymers was 60/40 mol %. The polymer discs were immersed in phosphate buffer solution at pH 7.4 and 37 degrees C for up to 364 days. After different time periods degradation products were extracted from the buffer solution and analyzed. In addition mass loss, water absorption, molecular weight changes, and changes in thermal properties were determined. The results show that the release rate of acidic degradation products, a possible cause of acidic microclimates and inflammatory responses, is controllable through macromolecular design, i.e., different distribution of the weak linkages in the copolymers.

  • 321.
    Hakkarainen, Minna
    et al.
    University of Helsinki, Finland.
    Jansson, Robert
    University of Helsinki, Finland.
    Sundholm, Francesca
    University of Helsinki, Finland.
    Liquid-Crystalline Behavior Of Some Carboxylic-Acids1993In: Polymer Bulletin, ISSN 0170-0839, E-ISSN 1436-2449, Vol. 31, no 1, p. 43-48Article in journal (Refereed)
    Abstract [en]

    A series of 4-omega-carboxyalkoxyphenyl-4'-methoxybenzoates 2 underbar has been prepared. Compounds with a spacer length of n=3 and n=5 show liquid crystalline behaviour. The products were characterized by IR and H-1NMR -spectroscopy, mass spectrometry, optical microscopy and DSC -measurements. The compounds are potentially useful as side-groups in liquid-crystalline polymers.

  • 322.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Influence of low molecular weight lactic acid derivatives on degradability of polylactide2000In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 76, no 2, p. 228-239Article in journal (Refereed)
    Abstract [en]

    The presence of low molecular weight lactic acid derivatives in films enhanced the degradability of polylactide in a biotic medium. Two different biotic and abiotic series were investigated. The films used for the first abiotic and biotic series (a-l and b-1 films) initially contained some lactic acid and lactoyl lactic acid, while the films used for the second abiotic and biotic series (a-2 and b-2 films) did not originally contain them. The b-1 films decreased in molecular weight during 3 weeks in the biotic medium, while no molecular weight decrease was seen in the a-1 films aged in a corresponding abiotic mineral medium. The molecular weight for the a-2 and b-2 films without lactic and lactoyl lactic acid remained almost constant. Scanning electron microscopy micro-graphs showed a larger amount of bacteria and fungi growing on the surface of b-1 films compared to b-2 films; thus, the presence of easily assimilated lactic acid and lactoyl lactic acid in the films improved the initial growth of microorganisms on the film surfaces. Gas chromatography and mass spectrometry analysis showed that lactic acid and lactoyl lactic acid were rapidly assimilated from the films aged in a biotic medium. New degradation products (e.g., ethyl ester of lactoyl lactic acid, acetic acid, and propanoic acid) were formed during aging in a biotic medium. Acetic acid and propanoic acid were formed as intermediate degradation products during the initial stages, but they were no longer detected after prolonged aging. The concentration of the ethyl ester of lactoyl lactic acid increased with aging time.

  • 323.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Rapid (bio)degradation of polylactide by mixed culture of compost microorganisms - low molecular weight products and matrix changes2000In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 41, no 7, p. 2331-2338Article in journal (Refereed)
    Abstract [en]

    Poly(L-lactide) (PLLA) was rapidly (bio)degraded by a mixed culture of compost microorganisms. After 5 weeks in biotic environment, the films had fragmented to fine powder, while the films in corresponding abiotic medium still looked intact. Analysis of the low molecular weight products by GC-MS showed that microorganisms rapidly assimilated lactic acid and lactoyl lactic acid from the films. At the same time, a new degradation product, ethyl ester of lactoyl lactic acid was formed in the biotic environment. This product cannot be formed by abiotic hydrolysis and it was not detected in the abiotic medium. The degradation of the PLLA matrix was monitored by differential scanning calorimetry (DSC), size exclusion chromatography (SEC) and scanning electron microscopy (SEM). A rapid molecular weight decrease and increasing polydispersity was observed in the biotic environment. In the abiotic environment only a slight molecular weight decrease was seen and the polydispersity started decreasing towards 2.0. This indicates different degradation mechanisms, i.e. preferred degradation near the chain ends in the biotic environment and a random hydrolysis of the ester bonds in the abiotic environment. SEM micrographs showed the formation of patterns and cracks on the surface of the films aged in biotic medium, while the surface of the sterile films remained smooth. The SEM micrographs showed a large number of bacteria and mycelium of fungi growing on the surface of the biotically aged films.

  • 324.
    Halonen, Helena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Larsson, Per Tomas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Iversen, Tommy
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Mercerized cellulose biocomposites: A study of influence of mercerization on cellulose supramolecular structure, water retention value and tensile properties2013In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 20, no 1, p. 57-65Article in journal (Refereed)
    Abstract [en]

    In this study the effect of the mercerization degree on the water retention value (WRV) and tensile properties of compression molded sulphite dissolving pulp was evaluated. The pulp was treated with 9, 10, or 11 % aqueous NaOH solution for 1 h before compression molding. To study the time dependence of mercerization the pulp was treated with 12 wt% aqueous NaOH for 1, 6 or 48 h. The cellulose I and II contents of the biocomposites were determined by solid state cross polarization/magic angle spinning carbon 13 nuclear magnetic resonance (CP/MAS 13C NMR) spectroscopy. By spectral fitting of the C6 and C1 region the cellulose I and II content, respectively, could be determined. Mercerization decreased the total crystallinity (sum of cellulose I and cellulose II content) and it was not possible to convert all cellulose I to cellulose II in the NaOH range investigated. Neither increased the conversion significantly with 12 wt% NaOH at longer treatment times. The slowdown of the cellulose I conversion was suggested as being the result from the formation of cellulose II as a consequence of coalescence of anti-parallel surfaces of neighboring fibrils (Blackwell et al. in Tappi 61:71–72, 1978; Revol and Goring in J Appl Polym Sci 26:1275–1282, 1981; Okano and Sarko in J Appl Polym Sci 30:325–332, 1985). Compression molding of the partially mercerized dissolving pulps yielded biocomposites with tensile properties that could be correlated to the decrease in cellulose I content in the pulps. Mercerization introduces cellulose II and disordered cellulose and lowered the total crystallinity reflected as higher water sensitivity (higher WRV values) and poorer stiffness of the mercerized biocomposites.

  • 325.
    Halysh, Vita
    et al.
    Igor Sikorsky Kyiv Polytech Inst, Peremogy Ave 37-4, UA-03056 Kiev, Ukraine.;Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Sevastyanova, Olena
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    de Carvalho, Danila Morais
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Riazanova, Anastasiia
    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.
    Lindström, Mikael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Gomelya, Mykola
    Igor Sikorsky Kyiv Polytech Inst, Peremogy Ave 37-4, UA-03056 Kiev, Ukraine..
    Effect of oxidative treatment on composition and properties of sorbents prepared from sugarcane residues2019In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 139, article id UNSP 111566Article in journal (Refereed)
    Abstract [en]

    Efficient sorbents for the removal of cationic dye were prepared from sugarcane bagasse (stalk) and straw (leaves) by oxidative pre-treatment with hydrogen peroxide (H2O2) in acetic acid. The effects of variables, such as concentration of H2O2, temperature and time on the properties of the fiber sorbents obtained were studied according to a 2(3) full-factorial design. For comparison, an oxidative treatment of sugarcane biomass with glacial acetic acid was also used. The yields of the materials obtained and their chemical composition were characterized and compared. Fourier transform infrared spectroscopy, field-emission scanning electron microscopy and benzene vapor adsorption were used to investigate the structural properties and morphology of the initial materials and sorbents. The sorption of methylene blue dye was used to assess the efficiency of dye removal by the sorbents. The pre-treatment conditions significantly affected the sorbent yield, their chemical composition (contents of cellulose, lignin and ash) as well as their sorption properties. The cellulosic sorbent (C-sorbent) from sugarcane bagasse obtained by pre-treatment with H2O2 in acetic acid and the lignocellulosic sorbent (LC-sorbent) from sugarcane straw obtained by pre-treatment with glacial acetic acid, had the highest sorption capacity for the methylene blue dye. For both types of sorbents, the sorption capacity increased with chemical pretreatment as a result of an increase in pore volume.

  • 326. Hansson, E.
    et al.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Multiple headspace single-drop microextraction - a new technique for quantitative determination of styrene in polystyrene2006In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1102, no 1-2, p. 91-95Article in journal (Refereed)
    Abstract [en]

    Single-drop microextraction (SDME), an emerging miniaturised extraction technique, was for the first time combined with multiple headspace extraction (MHE) to enable the quantitative determination of volatiles in solid matrixes by SDME technique. The concept of multiple headspace single-drop microextraction (MHS-SDME) was then applied for quantitative determination of styrene in polystyrene (PS) samples. Good linearity for the multiple headspace extraction was obtained when the migration of styrene was facilitated by grinding the samples and incubating them for 1 h at 150 degrees C prior the first extraction. Two microlitres of butyl acetate was used as the single-drop microextraction solvent and the extraction time was 5 min per cycle. The relative standard deviation (RSD) for single-drop microextraction of styrene standard at n = 6 was 7.6%. Linearity was shown for styrene concentrations between 0.005 and 0.75 mu g/ml (R-2 = 0.999). This corresponds to total amount of styrene between 0.1 and 15 mu g. The limit of quantitation for styrene standard at S/N 10 was 0.005 mu g/ml. The developed method was validated against and showed good agreement with an earlier reported dissolution-precipitation method.

  • 327.
    Hansson, Susanne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Antoni, Per
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Bergenudd, Helena
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Selective cleavage of polymer grafts from solid surfaces: assessment of initiator content and polymer characteristics2011In: POLYM CHEM, ISSN 1759-9954, Vol. 2, no 3, p. 556-558Article in journal (Refereed)
    Abstract [en]

    A novel initiator for atom transfer radical polymerization, also allowing for selective cleavage of polymer grafts, was designed and immobilized on a solid substrate. After cleavage, the initiator content was determined by utilizing Ellman's reagent and the cleaved polymer grafts were isolated and characterized by size exclusion chromatography.

  • 328.
    Hansson, Susanne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Toward Industrial Grafting of Cellulosic Substrates via ARGET ATRP2015In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 132, no 6, p. 41434-Article in journal (Refereed)
    Abstract [en]

    For the past decade, the interest in controlled grafting of cellulose has increased immensely. Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) has attracted the most interest; however, the sensitivity of this system has so far hindered its utilization in industry. In this study, filter paper, dissolving pulp, bleached and unbleached Kraft-pulp, and chemi-thermomechanical pulp papers were grafted with methyl methacrylate, employing activators regenerated by electron transfer (ARGET) ATRP. The reactions were performed in bulk or with small amounts of aqueous solutions, with no deoxygenation performed. To further demonstrate the robustness of this method towards simpler and more industry-friendly processes, the polymerizations were conducted in glass jars with screw lids. The possibility of recycling the reaction solution was also explored. We believe his thorough study to be an important step towards industrializing the "grafting-from" concept, and the results herein can most likely be extended to other surfaces and monomers.

  • 329.
    Hansson, Susanne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Tischer, Thomas
    Karlsruhe Institute of Technology (KIT).
    Goldmann, Anja S.
    Karlsruhe Institute of Technology (KIT).
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Barner-Kowollik, Christopher
    Karlsruhe Institute of Technology (KIT).
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Comparison of the grafting-from and grafting-to approaches when modifying cellulose via ARGET ATRP2012Conference paper (Other academic)
  • 330.
    Hansson, Susanne
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Tischer, Thomas
    Karlsruhe Institute of Technology (KIT).
    Goldmann, Anja S.
    Karlsruhe Institute of Technology (KIT).
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Barner-Kowollik, Christopher
    Karlsruhe Institute of Technology (KIT).
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Comparison of the grafting-from and grafting-to approaches when modifying cellulose via ARGET ATRP2012Conference paper (Other academic)
  • 331.
    Hansson, Susanne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Tischer, Thomas
    Goldmann, Anja S.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Barner-Kowollik, Christopher
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Visualization of poly(methyl methacrylate) (PMMA) grafts on cellulose via high-resolution FT-IR microscopy imaging2012In: Polymer Chemistry, ISSN 1759-9954, Vol. 3, no 2, p. 307-309Article in journal (Refereed)
    Abstract [en]

    Cellulose surfaces grafted with PMMA of different graft lengths were characterized via high-resolution FT-IR microscopy imaging, visualizing the polymer distribution on the surface. The results from the FT-IR measurements can be compared with the molecular weights obtained from SEC and (1)H NMR of the macromolecules formed in solution.

  • 332.
    Haraldsson, Klas Tommy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fabrication of polymeric microfluidic devices via photocurable liquid monomers2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Microfluidic devices have long been considered an ideal tool for rapid and inexpensive chemical analysis and reactions in areas ranging from point-of-care health to national security applications. However, fabricating microfluidic devices is time consuming, difficult and above all expensive. In commercial applications many thousand units need to be sold before the development costs are recovered. The problem is compounded since most microfluidic devices do not have generalized architectures which means that each end use requires a specialized design. The microfluidics marketplace can therefore be seen as being composed of 1000’s of niche markets.

    To address development costs, there is clearly a need for a versatile technology that can be used for many different applications and that enables rapid testing and optimization of new designs. This work describes such a technology: Contact Liquid Photolithographic Polymerization (CLiPP).

    The thesis consists of two parts: polymerization kinetics and the fabrication of polymeric microfluidic devices via CLiPP.

    The photopolymerization kinetics is evaluated for a number of monomer types, and the results are used to assess their suitability in the CLiPP process. Vinyl ether/maleate photoinitiated copolymerization is examined in detail. It is shown that the polymerization kinetics is dramatically influenced by the availability of easily abstractable hydrogens The presence of α-hydrogens adjacent to the vinyl ether functional group reduces the polymerization rate and the dependence of the polymerization rate as a function of initiation rate. Also, photoinitiated acrylate and methacrylate polymerization kinetics are presented. The kinetics results in these three monomer types are used to explain the different patterning properties of the monomer functionalities used in the CLiPP process, in which acrylates show enhanced patterning properties compared to methacrylates. The polymerization kinetics is studied with traditional tools and methods: photo Differential Scanning Calorimetry (photo-DSC), photo Fourier Transform Real Time Infrared Spectroscopy (photo-RTIR), and photo Real Time Electron Paramagnetic Spectroscopy (ESR).

    The microfluidic fabrication is performed via both in-house fabricated and commercially available CLiPP-specific hardware. The patterning qualities of the structures are evaluated via Scanning Electron Microscopy (SEM) and Optical Microscopy. The finished devices are used in their intended environment and evaluated in suitable manners to assess their utility.

    In this thesis, the development and design of specialized CLiPP fabrication machines, fabrication techniques and resulting microfluidic device features are presented anddiscussed. It is shown that the CLiPP scheme enables features such as 3 dimensional (3D) capabilities for minimized device footprints, a very large number of polymeric materials for optimized device components as well as facile integration of prefabricated components. Also, covalent layer adhesion and permanent surface modifications via living radical processes are demonstrated. These capabilities are exemplified in a number of examples that range from a 3D fluidic channel maze with separated fluidic streams and a device with independently moveable parts to a device constructed from multiple polymeric materials and devices with permanently modified surfaces, Also, batch processing capabilities are shown through fabrication of 400 identical undercut microstructures.

    Rapid and inexpensive design evaluations, multiple materials capabilities and the ability to seamlessly incorporate prefabricated microstructures of the CLiPP process strongly encourages continued method development. The future work that remains to be addressed is divided into two parts. First, to enable novel research devices, new polymer materials with enhanced mechanical and surface properties must be developed. Also, integration of prefabricated microstructures such as sensors and actuators has to be incorporated in a reproducible and rational manner. Secondly, to enable device mass fabrication, new automated equipment is to be developed in order to utilize the full batch processing potential of CLiPP.

  • 333.
    Haraldsson, Klas Tommy
    et al.
    Department of Chemical and Biological Engineering, ECCH 111, UCB424, University of Colorado.
    Hutchison, J.
    Department of Chemical and Biological Engineering, ECCH 111, UCB424, University of Colorado.
    Sebra, Robert
    Department of Chemical and Biological Engineering, ECCH 111, UCB424, University of Colorado.
    Good, Brian
    Department of Chemical and Biological Engineering, ECCH 111, UCB424, University of Colorado.
    Anseth, Kristi
    Department of Chemical and Biological Engineering, ECCH 111, UCB424, University of Colorado.
    Bowman, Christopher
    Department of Chemical and Biological Engineering, ECCH 111, UCB424, University of Colorado.
    3D Polymeric Microfluidic Device Fabrication via Contact Liquid Photolithographic Polymerization (CLiPP)2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 113, no 1, p. 454-460Article in journal (Refereed)
    Abstract [en]

    In this contribution, a new method for the fabrication of complex polymeric microfluidic devices is presented. The technology, contact liquid photolithographic polymerization (CLIPP). overcomes many of the draw backs associated kith other rapid prototyping schemes, such as limited materials choices and time-consuming microassembly protocols. CUPP shares many traits with other photolithographic methods, but three distinct features: (i) liquid photoresists in contact with the photomask. (ii) readily removed sacrificial Materials. and (iii) living radical processes, enable multiple polymeric chemistries and mechanical properties while simultaneously enabling facile fabrication of 3D geometries and surface chemistry control. This contribution details fabrication techniques and methods for the fabrication of high aspect ratio posts covalently bonded to a polymeric substrate, an array of independently stacked bars on top of perpendicular bars, multiple undercut structures fabricated simultaneously, and a complex 3D geometry with intertwined channels.

  • 334.
    Haraldsson, Klas Tommy
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Bowman, Christopher N.
    Hult, Anders
    KTH, Superseded Departments, Fibre and Polymer Technology.
    The Effects of Hydrogen Abstraction on the Kinetics of Monofunctional Maleate/ Vinyl Ether Radical PhotopolymerizationsManuscript (Other academic)
  • 335.
    Haraldsson, Klas Tommy
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    The Effects of Abstractable Hydrogen in Radical Photopolymerization of Maleate/Vinyl Ether Monomers Studied with EPR and Photo-RTIR2010In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 48, no 13, p. 2810-2816Article in journal (Refereed)
    Abstract [en]

    In this contribution, the influence of abstractable hydrogen on the kinetics of photopolymerized vinyl ether/maleate monomer formulations is reported. The effects of chain transfer on the polymerization rate were studied with photo real-time Infra Red (IR) for formulations composed of equimolar amounts of diethyl (DEMA) and three different vinyl ethers; methyl hexyl vinyl ether where the abstractable hydrogens adjacent to the vinyl functionality have been replaced with methyl groups, ethyl hexyl vinyl ether (EHVE) which has two easily abstractable alpha-hydrogens and triethylene glycol methyl vinyl ether (TEGMVE), which has several abstractable hydrogens. Four conclusions are drawn from these studies: (i) the vinyl ether/maleate kinetics differs significantly from the classical expression R-p = KI0.5, with recorded exponential factors of 0.84 +/- 0.04 in the absence of easily abstractable hydrogens; (ii) the presence of abstractable hydrogens significantly changes the kinetics of vinyl ether/maleate polymerizations with recorded exponential factors of 0.55 +/- 0.04 for EHVE/DEMA and 0.70 +/- 0.04 for TEGMVE/DEMA; (iii) the presence of easily abstractable hydrogens leads to a preferential consumption of maleates; and (iv) electron paramagnetic resonance studies show that vinyloxy-like radicals constitute the majority of the radicals in the systems with easily abstractable hydrogens.

  • 336.
    Haraldsson, Klas Tommy
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Passeraub, P. A.
    Fabrication of a Geometrically Complex Brain Slice Perfusion Device via Contact Liquid Photolithographic Polymerization (CLiPP)2005In: 4M 2005: First International Conference on Multi-Material Micro Manufacture, 2005, p. 427-430Conference paper (Other academic)
  • 337. Harrisson, Simon
    et al.
    Drisko, Glenna L.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Wooley, Karen L.
    Hybrid Rigid/Soft and Biologic/Synthetic Materials: Polymers Grafted onto Cellulose Microcrystals2011In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 12, no 4, p. 1214-1223Article in journal (Refereed)
    Abstract [en]

    Rigid nanoscale polymer rods were prepared by grafting preformed amine-terminated poly(styrene) and poly(tert-butyl acrylate) onto oxidized cellulose microcrystals. Low polydispersity polymers, grown using atom transfer radical polymerization, were characterized and purified prior to cellulose attachment. Oxidation of the cellulose microcrystal led to the formation of carboxylic acids on the surface of the microcrystals. Covalent attachment of the polymers onto the cellulose microcrystals was achieved via a carbodiimide-mediated amidation reaction. The length and diameter of the polymer-cellulose composites increased upon surface modification. Typically, polymer-cellulose composites are synthesized by a grafting-from method because it can be difficult to obtain sufficient graft density using a grafting-to preparation. However, the composites reported here comprised 60-64% grafted polymer by mass. This degree of grafting-to allowed the composite to form stable suspensions in organic solvents.

  • 338.
    Hassanzadeh, Salman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adolfsson, Karin H.
    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.
    Controlling the cooperative self-assembly of graphene oxide quantum dots in aqueous solutions2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 71, p. 57425-57432Article in journal (Refereed)
    Abstract [en]

    Fascinating 3D cooperative self-assembly behavior was observed for 2D graphene oxide quantum dots (GOQDs) in dilute and semi dilute aqueous solutions. In addition the optical properties could be tuned by controlling the supramolecular structures. While the electrostatic interactions between the charged single sheets were assigned as the main secondary interactions that were responsible for the supramolecular fine structures, the concentration, temperature, salt concentration and pH could tune the repulsive/attractive forces and the molecular binding between the GOQD sheets. The morphological studies combined with UV-Vis and fluorescence evaluations proved that after a slow nucleation step, elongation preceded radially by H-aggregate self-association of the GOQD monomers, forming the final porous spheres by radial growth of rods. The quenching properties of the self-associated-assembled GOQDs together with the excitation wavelengths of the GOQD solutions enabled tuning of the fluorescence intensity and color of the final solutions, which could be utilized for e.g. bioimaging and smart spectroscopy.

  • 339.
    Hassanzadeh, Salman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wu, Duo
    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.
    Supramolecular Assembly of Biobased Graphene Oxide Quantum Dots Controls the Morphology of and Induces Mineralization on Poly(epsilon-caprolactone) Films2016In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, no 1, p. 256-261Article in journal (Refereed)
    Abstract [en]

    Biobased 2D graphene oxide quantum dots (GOQDs) were synthesized from waste paper via carbon nanosphere intermediates and evaluated as property-enhancing additives for poly(epsilon-caprolactone) (PCL). The morphology of PCL films was controlled by supramolecular assembly of the small, 2D GOQDs in the polymer matrix. Phase behavior studies of PCL-GOQD in the solid state indicated concentration-dependent self-association of GOQD sheets, which was confirmed by SEM observations. Depending on the GOQD concentration, the formation of, e.g., spheres and stacked sheets was observed. GOQDs also induced mineralization on the surface of the films. A calcium phosphate (CaP) mineralization test revealed that the density of growing CaP crystals was controlled by the type of GOQD aggregates formed. Thus, utilization of the aggregation behavior of small GOQD sheets in polymeric matrices paves the way for tuning the morphology and properties of nanocomposites.

  • 340.
    Hassanzadeh, Salman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Aminlashgari, Nina
    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.
    Chemo-selective high yield microwave assisted reaction turns cellulose to green chemicals2014In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 112, p. 448-457Article in journal (Refereed)
    Abstract [en]

    Exceptionally high cellulose liquefaction yields, up to 87% as calculated from the amount of solid residue, were obtained under mild conditions by utilizing the synergistic effect of microwave radiation and acid catalysis. The effect of processing conditions on degradation products was fingerprinted by rapid laser desorption ionization-mass spectrometry (LDI-MS) method. The reaction was chemo-tunable, enabling production of glucose (Glc) or levulinic acid (LeA) at significantly high selectivity and yields, the relative molar yields being up to 50 and 69%, respectively. A turning point from pure depolymerization to glucose to further degradation to levulinic acid and formic acid was observed at approximately 50% liquefaction or above 140 degrees C. This was accompanied by the formation of small amounts of solid spherical carbonized residues. The reaction was monitored by multiple analytical techniques. The high yields were connected to the ability of the process to break the strong secondary interactions in cellulose. The developed method has great potential for future production of green platform chemicals.

  • 341. Hassanzadeh, Salman
    et al.
    Feng, Zhaoxuan
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    A proof-of-concept for folate-conjugated and quercetin-anchored pluronic mixed micelles as molecularly modulated polymeric carriers for doxorubicin2015In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 74, p. 193-204Article in journal (Refereed)
    Abstract [en]

    Pluronic, F127 (PEG-PPO-PEG, Mn = 12,500 g/mol) and reverse pluronic, 10R5 (PPO-PEG-PPO, Mn = 2000 g/mol) were molecularly modulated to reach multifunctional mixed micelle systems aiming to overcome some of the inherent weaknesses of pluronic based drug delivery systems. Targeting function was introduced by covalent attachment of folic acid to F127 (F127-FA), while quercetin was anchored to 10R5 (P-Q). The successful syntheses were evidenced by H-1 NMR, FTIR, DSC and UV-Vis. The proof-of-concept for the mixed micelles prepared from the drug anchored pluronics was demonstrated through reduced CMCs, slower release rates and increased Doxorubicin (DOX) encapsulation capacity from similar to 19% to similar to 43%. Quercetin therefore boosted the interactions of DOX with the hydrophobic core of the micelles. This was further evidenced by colloidal probe AFM which demonstrated almost doubled adhesion forces between the DOX coated probe and the quercetin modified pluronic as compared to the plain pluronic. The pre-biological essay of the DOX-modulated mixed micelle demonstrates promising properties. In addition quercetin has previously been proposed as combinatory drug to DOX enhancing its therapeutic function and reducing the side effects to normal cells.

  • 342.
    Hatton, Fiona L.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kedzior, S. A.
    Cranston, E. D.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Grafting-from cellulose nanocrystals via photoinduced Cu-mediated reversible-deactivation radical polymerization2017In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 157, p. 1033-1040Article in journal (Refereed)
    Abstract [en]

    In this work we describe the grafting of cellulose nanocrystals (CNCs) by surface-initiated photoinduced Cu-mediated reversible-deactivation radical polymerization (RDRP). Initially, CNCs obtained through sulfuric acid hydrolysis were functionalized with a tertiary bromo-ester moiety as an initiating group for the subsequent RDRP of methyl acrylate, targeting three different degrees of polymerization for the polymer grafts: 50, 300 and 600. The polymerizations proceeded in DMSO in the presence of CuBr2 and Me6TREN as the catalytic system utilizing a UV source (λmax ≈ 360 nm). The technique proved highly versatile for the modification of CNCs with poly(methyl acrylate), where considerably high grafting was achieved in short reaction times (90 min), with simple purification steps. CNC morphology was maintained and polymer grafts were evident through FT-IR spectroscopy, thermal analysis, contact angle measurements, X-ray photoelectron microscopy and x-ray diffraction.

  • 343.
    Hatton, Fiona
    et al.
    KTH.
    Rogers, Hannah
    Univ Liverpool, Dept Chem, Liverpool, Merseyside, England..
    Dwyer, Andrew
    Univ Liverpool, Dept Chem, Liverpool, Merseyside, England..
    Chambon, Pierre
    Univ Liverpool, Dept Chem, Liverpool, Merseyside, England..
    Rannard, Steve
    Univ Liverpool, Dept Chem, Liverpool, Merseyside, England..
    Hyperbranched-polydendrons: A new branched linear-dendritic hybrid polymer architecture2015In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 250Article in journal (Other academic)
  • 344.
    He, Yunjuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Boluk, Yaman
    Univ Alberta, Dept Civil & Environm Engn, Edmonton, AB T6G 1H9, Canada.
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden.
    Deltin, Tomas
    PTE Coatings AB, Hammarsvagen 4, SE-59432 Gamleby, Sweden.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden.
    Corrosion protective properties of cellulose nanocrystals reinforced waterborne acrylate-based composite coating2019In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 155, p. 186-194Article in journal (Refereed)
    Abstract [en]

    The present investigation highlights corrosion protection of carbon steel by a waterborne acrylate-based matrix coating, with and without reinforcement by cellulose nanocrystals, by using electrochemical impedance spectroscopy in 0.1 M NaCl solution over a period of 35 days. Interactions between cellulose nanocrystals and the matrix coating were demonstrated by Fourier transform infrared spectroscopy. The results show that both coatings have high barrier performance but different protective characteristics during long-term exposure. The differences can be attributed to the reinforcement effect of cellulose nanocrystals caused by hydrogen bonding interactions between cellulose nanocrystals and the matrix coating.

  • 345.
    Hed, Yvonne
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Multifunctional Dendritic Scaffolds: Synthesis, Characterization and Potential applications2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The development of materials for advanced applications requires innovative macromolecules with well-defined structures and the inherent ability to be tailored in a straightforward manner. Dendrimers, being a subgroup of the dendritic polymer family, possess properties which fulfill such demands. They have a highly branched architecture with a high number of functional groups and are one of the most well-defined types of macromolecules ever synthesized. However, despite their well-defined nature and high functional density, traditional dendrimers commonly lack diverse chemical functionalities. Therefore, this thesis focuses on the synthesis of more complex dendritic materials to extend their tailoring capacity by introduction of dualfunctionalities for multipurpose actions. It covers the synthesis of dualfunctional dendrimers, dendritic modification of linear poly(ethylene glycol) polymers and cellulose surfaces, and the synthesis of linear dendritic hybrids. The building blocks enabling this synthesis, AB2C monomers, were also developed during this work. The orthogonal nature between click groups (azide, alkyne and alkene) and hydroxyl groups have efficiently been utilized for postfunctionalization by robust click chemistry and traditional esterification reactions. Furthermore, linear dendritic hybrids were synthesized, merging the properties of linear and dendritic macromolecules. The dendritic frameworks were tailored towards the production of bone fracture adhesives, novel biofunctional dendritic hydrogels, biosensors and micellar drug delivery vehicles.

  • 346.
    Hed, Yvonne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Zhang, Yuning
    Andrén, Olver C. J.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Zeng, Xianghui
    Nyström, Andreas M.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Side-by-side comparison of dendritic-linear hybrids and their hyperbranched analogs as micellar carriers of chemotherapeutics2013In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 51, no 19, p. 3992-3996Article in journal (Refereed)
    Abstract [en]

    Amphiphilic block copolymers are successfully synthesized possessing a hydrophobic dendritic component based on the bis-MPA monomer and a hydrophilic linear polyethylene glycol (PEG) component. The hybrids were either conjured in small scale using robust click reactions between perfect dendrons and linear PEG or multigram polycondensation of hyperbranched blocks from PEG. In all cases, the amphiphiles were assembled to micelles, were found nontoxic and successfully loaded with the chemotherapeutic doxorubicin.

  • 347.
    Hedenqvist, Mikael S.
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Yousefi, Hamid Reza
    KTH, Superseded Departments, Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Gedde, Ulf W.
    KTH, Superseded Departments, Polymer Technology.
    Trollsas, M.
    Hedrick, J. L.
    Transport properties of hyperbranched and dendrimer-like star polymers2000In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 41, no 5, p. 1827-1840Article in journal (Refereed)
    Abstract [en]

    Moisture transport properties were assessed by sorption and desorption measurements on hydroxyl-functional hyperbranched polyesters based on 2,2-bis(methylol) propionic acid (bis-MPA) as AB(2)-monomer with ethoxylated pentaerythritol. A series of these polymers with different molar masses were studied. For the first time, it is reported that sigmoidal sorption curves were successfully modelled using a time-dependent surface boundary concentration, where the relaxation time was obtained from the mechanical stress relaxation data. The zero concentration diffusivities were very small and comparable with the values of fully amorphous poly(vinyl alcohol). Both the diffusivity data and the stress relaxation data indicated that these materials were plasticized by moisture. Ethylene glycol transport properties were measured on a hexadecanoate(C16)-terminated bis-MPA hyperbranched polymer. The replacement of the hydroxyl groups with C16 paraffin tails resulted in an increase in solute diffusivity despite the fact that these polymers became semicrystalline. The shape of the desorption curves indicated that continuous micropores were present and facilitated mass transport. The moisture transport properties were also measured on a series of semicrystalline dendrimer-like star poly(epsilon-caprolactone(s)). The low measured densities of these highly crystalline dendrimers confirmed that the porosity, as indicated by the shape of the desorption curves, had to be discontinuous. The porosity in the (C16)-terminated and the poly(epsilon-caprolactone(s)) was impossible to eliminate by applying a high external pressure during crystallization. A collective view of all the results obtained confirm that the transport properties are primarily controlled by the hydroxyl group concentration.

  • 348.
    Hedenström, Hanna
    KTH, School of Chemical Science and Engineering (CHE).
    The Set-Up of a Foundation Colorant File for the Purpose of Color-Matching Foundations, With a View to Improving the Current Foundation Color-Matching Process in the Future2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The process of color-matching any color product is a process that can be quite complicated and requires great skill from a color analyst. As the name suggests color-matching is the process in which the color of a standard is obtained from a sample through careful inspection and precision in order for the colors to match up. It is a process that can vary in length dependent of the amount of pigments used.

     Foundations are a type of liquid emulsion cosmetic and consist of five main pigments; white (titanium dioxide), red, brown, yellow and black iron oxides. These five pigments can when mixed together result in hundreds of shades. One of the greatest challenges for cosmetics companies is to successfully manufacture these shades often from a benchmark, a desired shade, as well as maintaining this same shade when the batch is scaled up from lab production to factory.

     Oriflame is a direct-selling cosmetics company in which the Marketing department and Color Cosmetic department work closely in order to produce new products and shades for each catalogue. Liquid foundation shades are decided by the Marketing department and given to the Color Cosmetic department to color-match.

     Currently the process of color-matching is carried out through the visual assessment by the color analyst. In order to improve the efficiency and lead - time of the current method, Oriflame has drawn inspiration from other sectors dealing with color and taken the decision to color-match with the use of a spectrophotometer coupled with color-appropriate software. The method was divided into four separate processes; confirming a sample method presentation to the spectrophotometer, colorant file set-up & process, color-matching process with the color-appropriate software and color match comparison.

    The results showed that with an adequate sized colorant file a method for color-matching with a spectrophotometer was established. The lead-time could be decreased by, as much as 66.6 % and providing strong evidence that this is a valuable tool for color analysts working at Oriflame.

  • 349. Helden, Laurent
    et al.
    Eichhorn, Ralf
    KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
    Bechinger, Clemens
    Direct measurement of thermophoretic forces2015In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 11, no 12, p. 2379-2386Article in journal (Refereed)
    Abstract [en]

    We study the thermophoretic motion of a micron sized single colloidal particle in front of a flat wall by evanescent light scattering. To quantify thermophoretic effects we analyse the nonequilibrium steady state (NESS) of the particle in a constant temperature gradient perpendicular to the confining walls. We propose to determine thermophoretic forces from a "generalized potential" associated with the probability distribution of the particle position in the NESS. Experimentally we demonstrate, how this spatial probability distribution is measured and how thermophoretic forces can be extracted with 10 fN resolution. By varying temperature gradient and ambient temperature, the temperature dependence of Soret coefficient ST(T) is determined for r = 2.5 mm polystyrene and r = 1.35 mm melamine particles. The functional form of ST(T) is in good agreement with findings for smaller colloids. In addition, we measure and discuss hydrodynamic effects in the confined geometry. The theoretical and experimental technique proposed here extends thermophoresis measurements to so far inaccessible particle sizes and particle solvent combinations.

  • 350.
    Henschen, Jonatan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Dongfang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ek, Monica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Preparation of cellulose nanomaterials via cellulose oxalates2019In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 213, p. 208-216Article in journal (Refereed)
    Abstract [en]

    Nanocellulose prepared from cellulose oxalate has been discussed as an alternative to other methods to prepare cellulose nanofibrils or crystals. The current work describes the use of a bulk reaction between pulp and oxalic acid dihydrate to prepare cellulose oxalate followed by homogenization to produce nanocellulose. The prepared nanocellulose is on average 350 nm long and 3–4 nm wide, with particles of size and shape similar to both cellulose nanofibrils and cellulose nanocrystals. Films prepared from this nanocellulose have a maximum tensile stress of 140–200 MPa, strain at break between 3% and 5%, and oxygen permeability in the range of 0.3–0.5 cm 3 μm m −2 day −1 kPa −1 at 50% relative humidity. The presented results illustrate that cellulose oxalates may be a low-cost method to prepare nanocellulose with properties reminiscent of those of both cellulose nanofibrils and cellulose nanocrystals, which may open up new application areas for cellulose nanomaterials.

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