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  • 1.
    Abdi, Sofia
    KTH, Skolan för kemivetenskap (CHE).
    Preparation and process optimization of encapsulating cellulose microspheres2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Microspheres are spherically shaped particles within the size range of 1-1000 μm in diameter.

    Due to the their small size and round shape, microspheres show many advantages in various

    applications such as pharmaceuticals, composites and coatings. The microspheres can be

    customized to fit a specific application and are manufactured in various forms such as solid,

    hollow and encapsulating.

    Encapsulating cellulose microspheres have been produced in this project by the emulsionsolvent

    evaporation technique. The purpose of this study was to further investigate the

    possibility of producing encapsulating microspheres with a size range of 10-50 μm that will

    have a high encapsulation. A second purpose of this study was optimizing the emulsifier

    system for the preparation of these spheres. This has been accomplished by varying several

    process parameters such as type of emulsifiers and solvents to study the effect on morphology

    and encapsulation efficiency. The analyses of the spheres were performed with optical

    microscopy, thermal gravimetric analyzer (TGA) and scanning electron microscopy (SEM).

    The emulsifier type and concentration affected the encapsulation and size distribution but had

    no direct effect on the internal and external structure, which was multi-cellular and porous,

    respectively. The highest encapsulation in relation to average size was obtained with 0.1 v/v-

    % of the emulsifier mixture Emulsifier 1 (E1)/Emulsifier 2 (E2) (70/30 %). The solvent used

    to dissolve the polymer had a direct effect on encapsulation, a combination of Solvent 2 (S2)

    and Solvent 1 (S1) proved best for the three tested cellulose derivatives with low, medium and

    high number average molecular weight. The solvent also had an effect on the internal

    structure of the microspheres, becoming more core-shell when using the S1/S2 combination.

    Fulltekst (pdf)
    fulltext
  • 2. Adamus, Grazyna
    et al.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Höglund, Anders
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Kowalczuk, Marek
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    MALDI-TOF MS Reveals the Molecular Level Structures of Different Hydrophilic-Hydrophobic Polyether-esters2009Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, nr 6, s. 1540-1546Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 3.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Huang, Ping
    Department of Chemistry – Ångström Laboratory, Uppsala University, Box 523, Uppsala, 751 20, Sweden, Box 523.
    Golda-Cepa, Monika
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Xu, Huan
    School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, P. R. China.
    Kotarba, Andrzej
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Scavenging of DPPH by Persistent Free Radicals in Carbonized Particles2023Inngår i: Advanced Sustainable Systems, E-ISSN 2366-7486, Vol. 7, nr 3, artikkel-id 2200425Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Persistent free radicals (PFR) in carbonized particles may play a role in degradation of environmental compounds. The influence of PFR is evaluated in various carbonized particles on their radical scavenging efficiency upon the common radical indicator 2-2-diphenyl-1-picrylhydrazyl (DPPH). Carbonized particles are derived by hydrothermal carbonization of glucose (C-W) or glucose and urea (NC-W) and ionothermal carbonization of glucose and urea ionic liquid (IL) (NC-IL). The carbonized materials contain OH/COOH, C=C, and C-O functionalities. The addition of urea introduces NH/NH2 functionalities. The content of polar surface groups is lower in IL-processed NC-IL. The scavenging ability, measured as DPPH UV–vis absorption decline, increases with concentration and time for all particles, while the efficiency changes are in the order of C-W > NC-W > NC-IL. Electron paramagnetic resonance analysis reveals similar radical concentration in all carbonized materials studied. The difference in efficiency is, thus, not directly related to the PFR concentration but rather to the type of PFR, surface functionalities and/or scavenging mechanism. According to the g-values, radicals in these particles are carbon-centered. The minor variation in g-values suggests interactions between the radicals and their environmental functional groups. This provides insights into the influence of PFR in carbonized materials on their radical scavenging efficiency.

  • 4.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lin, Chia-feng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Microwave Assisted Hydrothermal Carbonization and Solid State Postmodification of Carbonized Polypropylene2018Inngår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 6, nr 8, s. 11105-11114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Functional carbon materials produced through a hydrothermal treatment of waste products have gained interest. Particularly, the method is considered more facile and green compared to conventional decomposition methods. Here, we demonstrated an upcycling of polypropylene (PP) waste to carbon materials by a microwave assisted hydro thermal treatment. The solid product obtained from the hydrothermal treatment was analyzed by multiple techniques to reveal the structure and the influence of processing conditions on PP degradation and hydrothermal carbonization. Chemical analyses showed the presence of carbonaceous material independent of acid amount (20 and 30 mL), temperature (210 and 250 degrees C), and time (20-80 min). A complete transformation of PP content to amorphous carbon required 60 min at 250 degrees C. The mass yield of the solid product decreased as a function of harsher processing conditions. At the same time, thermogravimetric analysis illustrated products with increasing thermal stability and a larger amount of remaining residue at 600 degrees C. The solid products consisted of irregular fragments and sheet-like structures. A solid state microwave process in air atmosphere was performed on a product with incomplete carbonization. The modification resulted in a decreased C/O ratio, and TGA analysis in nitrogen showed high thermal stability and degree of carbonization as indicated by the remaining residue of 86.4% at 600 degrees C. The new insights provided on the hydrothermal carbonization, and postmodification in air atmosphere, can catalyze effective handling of plastic waste by enabling transformation of low quality waste into functional carbon materials.

  • 5.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Sjöberg, I.
    Höglund, O. V.
    Wattle, O.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    In Vivo Versus In Vitro Degradation of a 3D Printed Resorbable Device for Ligation of Vascular Tissue in Horses2021Inngår i: Macromolecular Bioscience, ISSN 1616-5187, E-ISSN 1616-5195, Vol. 21, nr 10, artikkel-id 2100164Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A resorbable 3D printed polydioxanone (PDO) device is manufactured to facilitate ligation of vascular tissue during surgery. The device must provide sufficient mechanical performance throughout the healing period. Therefore, degradation and mechanical performance of the device are investigated as a function of in vivo and in vitro aging. During aging the PDO device released cyclic and linear water-soluble products. In vivo aging resulted in higher relative number of linear oligomers in comparison to in vitro aging. A major loss of mechanical performance is observed after only 10 days in vivo and the Young’s modulus (E) and tensile strength at break (σb) decreased by 28% and 54%, respectively. This is in contrast to in vitro aging, where no loss of mechanical properties is observed during the same period. The in vivo aged devices exhibit clear holes in the matrices after 28 days, while apparent cracks are observed first after 140 days in vitro. These results highlight the sensitivity of the degradation process of resorbable devices with regards to the interactions of the device with the surrounding environment (tissues) and demonstrate the importance of in vivo testing as compliment to in vitro testing before clinical use of devices.

  • 6.
    Aguilar-Sanchez, Andrea
    et al.
    Stockholm Univ, Div Mat & Environm Chem, Frescativagen 8, S-10691 Stockholm, Sweden..
    Jalvo, Blanca
    Stockholm Univ, Div Mat & Environm Chem, Frescativagen 8, S-10691 Stockholm, Sweden..
    Mautner, Andreas
    Univ Vienna, Fac Chem, Inst Mat Chem & Res, Polymer & Composite Engn PaCE Grp, Wahringer Str 42, A-1090 Vienna, Austria..
    Nameer, Samer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Pohler, Tiina
    VTT Tech Res Ctr Finland, Solut Nat Resources & Environm, POB 1000, FI-02044 Espoo, Finland..
    Tammelin, Tekla
    VTT Tech Res Ctr Finland, Solut Nat Resources & Environm, POB 1000, FI-02044 Espoo, Finland..
    Mathew, Aji P.
    Stockholm Univ, Div Mat & Environm Chem, Frescativagen 8, S-10691 Stockholm, Sweden..
    Waterborne nanocellulose coatings for improving the antifouling and antibacterial properties of polyethersulfone membranes2021Inngår i: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 620, artikkel-id 118842Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article presents a waterborne nanocellulose coating process to change the surface characteristics and mitigate fouling of commercially available polyethersulfone (PES) microfiltration membranes. An extensive comparative study between nanoporous and nano-textured layers composed of cellulose nanocrystals (CNC) or TEMPO-oxidized cellulose nanofibrils (T-CNF), which were coated on the PES membrane by taking advantage of the electrostatic interactions between the PES substrate, a polyallylamine hydrochloride (PAHC1) anchoring layer, and the nanocellulose functional layer. Coated PES membranes exhibited decreased surface roughness and pore sizes as well as rejection of compounds with a M-w above 150 kDa, while the water permeability and mechanical properties of remained largely unaffected. The coatings improved the wettability as confirmed by a reduction of the contact angle by up to 52% and exhibited a higher negative surface charge compared to the uncoated membranes over a pH range of 4-8. A significant reduction in organic fouling was observed for the coated membranes demonstrated by bovine serum albumin (BSA) adsorption studies on T-CNF and CNC surfaces using Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), UV-vis spectroscopy and FTIR mapping after exposing the membranes to dynamic adsorption of BSA. The T-CNF coating exhibited effective antibacterial action against Escherichia coli (E. coli) attributed to the pH reduction effect induced by the carboxyl groups; while CNC coatings did not show this property. This work demonstrates a simple, green, and easy-to-scale layer-by-layer coating process to tune the membrane rejection and to improve antifouling and antibacterial properties of commercially available membranes.

  • 7.
    Ahlinder, Astrid
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi. KTH Royal Institute of Technology.
    Degradable copolymers in additive manufacturing: controlled fabrication of pliable scaffolds2021Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [sv]

    Inom vävnadsregenerering är produktionen av väldefinieradematriser med en porös arkitektur av nedbrytbara polymerer av stortintresse, dessa kan nu skapas genom additiva tillverkningsprocesser. Vidadditiv tillverkning krävs ett smalt munstycke för att skapa detaljrikastrukturer och detta ställer krav på att de reologiska egenskapernaanpassat. Lägre viskositet av smältan gör de lättare att använda, men enhög molmassa krävs för tillverka matriser där de mekaniska egenskapernakan bibehållas under tiden som krävs för vävnadsregenerering. Ytterligareen utmaning uppstår när nedbrytbara polymerer används i smältbaseradadditiva tillverkningsprocesser är att termisk nedbrytning ofta reducerarmolmassan redan under produktionsfasen. För att kunna användanedbrytbara polymerer av medicinsk kvalitet i smältbaserad additivtillverkning och samtidigt minimera den termiska nedbrytningen har, idenna avhandling, reologiska fingeravtryck av nedbrytbara syntetiskapolymerer med medicinsk kvalitet använts för att bestämmaprocessparametrar. Termisk nedbrytning beroende av processparamaterar har analyserats och minimeras i två smältbaserade additivatillverkningsprocesser.En additiv tillverkningsprocess var designad där nedbrytbarapolymerer av hög molmassa kunde användas utan termisk nedbrytning närprocessparametrar hade valts utifrån polymerens egenskaper. Kunskapenom användningen av dessa polymerer inom additiv tillverkning kundeappliceras på en sampolymer som utvecklats inom forskningsgruppen förmjukvävnad, poly(ε-kaprolakton-co-p-dioxanon) för att skapa böjbaramatriser. Genom att använda reologisk analys och polymerkarakteriseringerhölls processparametrar som möjliggjorde additiv tillverkning utantermisk nedbrytning. I tillägg till val av polymer och processparametrar såkan mekaniska egenskaper också styras av den strukturella designen.Poly(ε-kaprolakton) användes som modellmaterial för att reducerastyvheten med hjälp av designen, resultatet visade att det var möjligt medmer än en faktor 10 och mjuka böjbara matriser skapades.

    Fulltekst (pdf)
    fulltext
  • 8.
    Ahlström, Leon
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Evaluation of Woodmer/plastic composites2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Plast ger otroliga möjligheter i form av stor variation för materialanvändning. Tyvärr sker det dock på bekostnad av miljön då de ackumuleras i naturen. En kompromiss mellan hållbarhet och fortsatt plastanvändning skulle kunna vara att använda biomassa som fyllnadsmaterial i plastkompositer istället för plast. Detta skulle i sin tur minska mängden plast och öka användningen av förnybara råvaror. Naturligtvis måste de mekaniska och termiska egenskaperna också vara av acceptabel kvalitet för materialtillämpningar och helst även erbjuda någon form av uppgradering av det redan existerande materialet. Ett potentiellt fyllnadsmaterial är Woodmer, en LCC (lignin kolhydrat komplex) som produceras av Ecohelix. Woodmers förmåga att agera som ett termoplastiskt kompositmaterial analyserades och jämfördes med de respektive jungfruliga termoplasterna. Tre olika plaster används som bas för kompositerna och dessa plaster var akrylnitril-butadien-styren (ABS), polymjölksyra (PLA) och lågdensitetspolyeten (LDPE).

    Resultaten visar att det är möjligt att skapa homogena Woodmer/termoplast kompositmaterial. När det gäller de termiska egenskaperna, så gav inte UL 94 någon brandklassificering på materialen, några positiva effekter observerades i TGA och resultaten från DSC var mestadels oförändrade jämfört med respektive jungfrulig plast. Dragprovning visade å andra sidan att de mekaniska egenskaperna påverkas negativt av högre Woodmer tillsatser men effekten varierade kraftigt mellan de olika plasterna då LDPE var minst påverkad och PLA mest påverkad. Framtida forskning bör fokusera på att tillverka material genom dubbelskruv extrudering eftersom det tyvärr fanns problem med blandningen i enkelskruv extrudering. Ytterligare forskning kring materialens morfologi, löslighet och så vidare krävs också för att se om kompositerna är lämpliga material eller om det finns några oförutsedda problem.

    Fulltekst (pdf)
    fulltext
  • 9.
    Akan, Rabia
    KTH, Skolan för kemivetenskap (CHE).
    Oorganiska-organiska nanopartikelbaserade supramolekylära strukturer för biomedicinska applikationer2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The possibility to create a multifunctional nanoparticle system via supramolecular chemistry approach with ability to simultaneously target, deliver and diagnose was investigated. Superparamagnetic iron oxide nanoparticles were synthesized by co-precipitation method and surface modified with the cyclic oligosaccharide carboxymethyl-β-cyclodextrin by three different routes. The different routes involved one, two or three reaction steps in order to reach to the final oligosaccharide functionalized nanoparticles. Esterification was performed using the intrinsic hydroxyl functionality of the nanoparticle surfaces or amine functionality was introduced prior to amidization. Further, a polymeric coating was created by incorporation of folic acid functionalized Pluronic® L-35 into carboxymethyl-β-cyclodextrin. The resulting nanoparticle based supramolecular systems were characterized by TEM, TGA, FT-IR, DLS and zeta potential techniques.

     

    The colloidal stabilities of the supramolecular nanoparticle systems were investigated in phosphate buffered saline with pH 7.4 representing body conditions. It was found that a three-step functionalization of iron oxide nanoparticles with citric acid, hexamethylenediamine and finally carboxymethyl-β-cyclodextrin resulted in the most stable ferrofluids. The average size of the resulting carboxymethyl-β-cyclodextrin functionalized nanoparticles was 25 nm prior to, and 50 nm after inclusion of folic acid functionalized Pluronic. The amount of grafted carboxymethyl-β-cyclodextrin on the nanoparticles surfaces was 25 weight %. Thus, the resulting stable ferrofluid creates an efficient platform with potential of multiple uses in biomedicine. This nanoparticle based supramolecular system combines the properties of magnetic targeting and MRI contrast enhancement due to the superparamagnetic iron oxide nanoparticle core, drug delivery of hydrophobic drugs due to the polymer capsule and selective targeting towards tumour cells due to the folic acid.

  • 10.
    Akhlaghi, Shahin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Degradation of acrylonitrile butadiene rubber and fluoroelastomers in rapeseed biodiesel and hydrogenated vegetable oil2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biodiesel and hydrotreated vegetable oil (HVO) are currently viewed by the transportation sector as the most viable alternative fuels to replace petroleum-based fuels. The use of biodiesel has, however, been limited by the deteriorative effect of biodiesel on rubber parts in automobile fuel systems. This work therefore aimed at investigating the degradation of acrylonitrile butadiene rubber (NBR) and fluoroelastomers (FKM) on exposure to biodiesel and HVO at different temperatures and oxygen concentrations in an automated ageing equipment and a high-pressure autoclave. The oxidation of biodiesel at 80 °C was promoted by an increase in the oxygen partial pressure, resulting in the formation of larger amounts of hydroperoxides and acids in the fuel. The fatty acid methyl esters of the biodiesel oxidized less at 150 °C on autoclave aging, because the termination reactions between alkyl and alkylperoxyl radicals dominated over the initiation reactions. HVO consists of saturated hydrocarbons, and remained intact during the exposure. The NBR absorbed a large amount of biodiesel due to fuel-driven internal cavitation in the rubber, and the uptake increased with increasing oxygen partial pressure due to the increase in concentration of oxidation products of the biodiesel. The absence of a tan δ peak (dynamical mechanical measurements) of the bound rubber and the appearance of carbon black particles devoid of rubber suggested that the cavitation was caused by the detachment of bound rubber from particle surfaces. A significant decrease in the strain-at-break and in the Payne-effect amplitude of NBR exposed to biodiesel was explained as being due to the damage caused by biodiesel to the rubber-carbon-black network. During the high-temperature autoclave ageing, the NBR swelled less in biodiesel, and showed a small decrease in the strain-at-break due to the cleavage of rubber chains. The degradation of NBR in the absence of carbon black was due only to biodiesel-promoted oxidative crosslinking. The zinc cations released by the dissolution of zinc oxide particles in biodiesel promoted reduction reactions in the acrylonitrile part of the NBR. Heat-treated star-shaped ZnO particles dissolved more slowly in biodiesel than the commercial ZnO nanoparticles due to the elimination of inter-particle porosity by heat treatment. The fuel sorption was hindered in HVO-exposed NBR by the steric constraints of the bulky HVO molecules. The extensibility of NBR decreased only slightly after exposure to HVO, due to the migration of plasticizer from the rubber. The bisphenol-cured FKM co- and terpolymer swelled more than the peroxide-cured GFLT-type FKM in biodiesel due to the chain cleavage caused by the attack of biodiesel on the double bonds formed during the bisphenol curing. The FKM rubbers absorbed biodiesel faster, and to a greater extent, with increasing oxygen concentration. It is suggested that the extensive biodiesel uptake and the decrease in the strain-at-break and Young’s modulus of the FKM terpolymer was due to dehydrofluorination of the rubber by the coordination complexes of biodiesel and magnesium oxide and calcium hydroxide particles. An increase in the CH2-concentration of the extracted FKM rubbers suggested that biodiesel was grafted onto the FKM at the unsaturated sites resulting from dehydrofluorination.

    Fulltekst (pdf)
    fulltext
  • 11.
    Akhlaghi, Shahin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Amir Masoud, Pourrahimi
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Christian, Sjöstedt
    Martin, Bellander
    Mikael S., Hedenqvist
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ulf W., Gedde
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Degradation of fluoroelastomers in rapeseed biodiesel at different oxygen concentrations2017Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 136, s. 10-19Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The degradation of fluoroelastomers (FKM) based on different monomers, additives and curing systems was studied after exposure to rapeseed biodiesel at 100 °C and different oxygen partial pressures. The sorption of fuel in the carbon black-filled FKM terpolymer was promoted by the fuel-driven cavitation in the rubber. The bisphenol-cured rubbers swelled more in biodiesel than the peroxide-cured FKM, presumably due to the chain cleavage caused by the attack of biodiesel on the double bonds formed during the bisphenol curing. With any of the selected types of monomer, the FKM rubbers absorbed biodiesel faster and to a greater extent with increasing oxygen partial pressure due to the increase in concentration of the oxidation products of biodiesel. Water-assisted complexation of biodiesel on magnesium oxide and calcium hydroxide particles led to dehydrofluorination of FKM, resulting in an extensive fuel uptake and a decrease in the strain-at-break and the Young's modulus of the rubbers. An increase in the CH2-concentration determined by infrared spectroscopy, and the appearance of biodiesel flakes in scanning electron micrographs of the extracted rubbers, were explained as being due to the presence of insoluble biodiesel grafted onto FKM on the unsaturated sites resulting from dehydrofluorination. The extensibility of the GFLT-type FKM was the least affected on exposure to biodiesel because this rubber contained less unsaturation and metal oxide/hydroxide particles.

  • 12.
    Akhlaghi, Shahin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Pourrahimi, A. M.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Christian, Sjöstedt
    Martin, Bellander
    Mikael S., Hedenqvist
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ulf W., Gedde
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Effects of ageing conditions on degradation of acrylonitrile butadiene rubber filled with heat-treated ZnO star-shaped particles in rapeseed biodiesel2017Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The degradation of acrylonitrile butadiene rubber (NBR) after exposure to biodiesel at different oxygen partial pressures in an automated ageing equipment at 80 °C, and in a high-pressure autoclave at 150 °C was studied. The oxidation of biodiesel was promoted by an increase in oxygen concentration, resulting in a larger uptake of fuel in the rubber due to internal cavitation, a greater decrease in the strain-at-break of NBR due to the coalescence of cavity, and a faster increase in the crosslinking density and carbonyl index due to the promotion of the oxidation of NBR. During the high-temperature autoclave ageing, less fuel was absorbed in the rubber, because the formation of hydroperoxides and acids was impeded. The extensibility of NBR aged in the autoclave decreased only slightly due to the cleavage of rubber chains by the biodiesel attack. The degradation of NBR in the absence of carbon black was explained as being due to oxidative crosslinking. The dissolution of ZnO crystals in the acidic components of biodiesel was retarded by removing the inter-particle porosity and surface defects through heat treating star-shaped ZnO particles. The rubber containing heat-treated ZnO particles swelled less in biodiesel than a NBR filled with commercial ZnO nanoparticles, and showed a smaller decrease in the strain-at-break and less oxidative crosslinking.

    Fulltekst (pdf)
    fulltext
  • 13.
    Al Husseinat, Ali
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lignin Biorefining: Swelling and activation of fibers for lignin extraction2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I världens omvandling mot en bioekonomi kommer lignocellulosa material spela en stor roll i ersättningen av fossila resurser. Lignin är den mest tillgängliga källan av förnybara och naturligt förekommande aromatiska ämne och den utgör 15–30% av ved. Det lignin som är för nuvarande tillgängligt i marknaden är begränsat i sina appliceringar på grund av ämnets komplexa och outforskade kemisk struktur. I ett försök att bidra till ’lignin-först’ bioraffinaderi konceptet, undersöker detta arbete effekten av urea och karboxymetylering som förbehandlingsmetoder på utbyte av lignin såväl som de kemiska och fysiska egenskaperna av lignin. Karaktäriseringstekniker som Fourier-transform infra-red och nuclear magnetic resonance spectroscopy används för att analysera den kemiska strukturen av ligninet efter extraktion. Det resulterade i att båda förbehandlingsmetoder ökade utbytet av lignin med mellan 1% och 16%. Urea förbehandlingen hade ingen effekt på den kemiska strukturen av varken fibrer eller lignin. Men, karboxymetylering förbehandlingen ändrade i kemiska strukturen av lignin genom att lägga till karboxymetyl-grupper i både den alifatiska och den fenoliska regionen. Medans att öka förbehandlingstiden ökade utbyte i båda förbehandlingsmetoder, hade detta effekten att minska mängden kvantifierbara bindningar mellan enheterna för karboxymetylering förbehandlingen. Dessa diskuterade metoder har potential att användas i valorisering av lignin.

    Fulltekst (pdf)
    fulltext
  • 14.
    Alberdi-Muniain, Ane
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strukturakustik.
    Gil-Negrete, N.
    Department of Applied Mechanics, CEIT and Tecnun (University of Navarra).
    Kari, Leif
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strukturakustik.
    Influence of carbon black and plasticisers on dynamic properties of isotropic magnetosensitive natural rubber2012Inngår i: Plastics, rubber and composites, ISSN 1465-8011, E-ISSN 1743-2898, Vol. 41, nr 7, s. 310-317Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dynamic shear modulus of magnetosensitive (MS) natural rubber composites is experimentallystudied, where influences of carbon black, plasticiser and iron particle concentrations areinvestigated at various dynamic shear strain amplitudes and external magnetic fields within thelower structure borne frequency range. The iron particles embedded in natural rubber areirregularly shaped and randomly distributed; the plasticisers simplify the iron particle blendingprocess, while carbon black reduces the production costs and improves the mechanicalproperties. The results show that the relative MS effect on the shear modulus magnitude increaseswith increased plasticiser and iron particle concentration and decreases with increased carbonblack concentration. Furthermore, their relative contributions are quantified. Consequently, thestudy provides a basis for optimising the composition of MS natural rubber to meet a variety ofrequirements, including those of vibration isolation, a promising application area for MS materials.

  • 15.
    Albertsson, A-C.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Andersson, S-O.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    The mechanism of biodegradation of polyethylene1987Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 18, s. 73-87Artikkel i tidsskrift (Fagfellevurdert)
  • 16. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Degradation of enhanced environmentally degradable polyethylene in biological aqueous media: mechanisms during the first stages1994Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 51, nr 6, s. 1097-1105Artikkel i tidsskrift (Fagfellevurdert)
  • 17. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Increased biodegradation of a low-density polyethylene (LDPE) matrix in starch-filled LDPE materials1993Inngår i: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 1, nr 4, s. 241-245Artikkel i tidsskrift (Fagfellevurdert)
  • 18. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Solid-phase extraction and gas chromatographic-mass spectrometric identification of degradation products from enhanced environmentally degradable polyethylene1995Inngår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 690, nr 2, s. 207-217Artikkel i tidsskrift (Fagfellevurdert)
  • 19. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Susceptibility of enhanced environmentally degradable polyethylene to thermal and photo-oxidation1992Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 37, nr 2, s. 163-171Artikkel i tidsskrift (Fagfellevurdert)
  • 20. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Lindberg, T.
    Degradation product pattern and morphology changes as means to differentiate abiotically and biotically aged degradable polyethylene1995Inngår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 36, nr 16, s. 3075-83Artikkel i tidsskrift (Fagfellevurdert)
  • 21. Albertsson, A-C.
    et al.
    Griffin, G. J. L.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Nishimoto, K.
    Watanabe, Y.
    Spectroscopic and mechanical changes in irradiated starch-filled LDPE1994Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 45, nr 2, s. 173-178Artikkel i tidsskrift (Fagfellevurdert)
  • 22. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Abiotic degradation products from enhanced environmentally degradable polyethylene1994Inngår i: Acta Polymerica, ISSN 0323-7648, E-ISSN 1521-4044, Vol. 45, nr 2, s. 97-103Artikkel i tidsskrift (Fagfellevurdert)
  • 23. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Aspects of biodeterioration of inert and degradable polymers1993Inngår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 31, nr 3, s. 161-170Artikkel i tidsskrift (Fagfellevurdert)
  • 24. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Biodegradable polymers1992Inngår i: Comprehensive Polymer Science, Supplement Series, Midland, Michigan: Pergamon Press, 1992, s. 285-Kapittel i bok, del av antologi (Fagfellevurdert)
  • 25. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Biodegradation and testmethods for environmental and biomedical applications of polymers1990Inngår i: Degradable Materials, Boca Raton: CRC Press, 1990, s. 263-Kapittel i bok, del av antologi (Fagfellevurdert)
  • 26. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Chemistry and biochemistry of polymer biodegradation1994Inngår i: Chemistry and Technology of Biodegradable Polymers / [ed] G.J.L. Griffin, London, England: Blackie Academic & Professional , 1994, s. 7-17Kapittel i bok, del av antologi (Fagfellevurdert)
  • 27. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Chromatographic fingerprinting as a means to predict degradation mechanisms1996Inngår i: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 4, nr 1, s. 51-3Artikkel i tidsskrift (Fagfellevurdert)
  • 28. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Controlled degradation by artificial and biological processes1996Inngår i: Macromol. Design of Polymeric Materials, Marcel Dekker, 1996, s. 54-Kapittel i bok, del av antologi (Fagfellevurdert)
  • 29. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Degradable polyethylene-starch complex1991Inngår i: Makromolekulare Chemie, Macromolecular Symposia, Vol. 48-49, nr Eur. Polym. Fed. Symp. Polym. Mater., 3rd, 1990, s. 395-402Artikkel i tidsskrift (Fagfellevurdert)
  • 30. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Degradable Polymers1996Inngår i: The Polymeric Materials Encyclopedia: Synthesis, Properties and Applications / [ed] J. C. Salamone, Boca Raton, USA: CRC Press, 1996, s. 150-Kapittel i bok, del av antologi (Fagfellevurdert)
  • 31. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Degradable polymers for the future1995Inngår i: Acta Polymerica, ISSN 0323-7648, E-ISSN 1521-4044, Vol. 46, nr 2, s. 114-123Artikkel i tidsskrift (Fagfellevurdert)
  • 32. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Environment-adaptable polymers1993Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 41, nr 3, s. 345-349Artikkel i tidsskrift (Fagfellevurdert)
  • 33. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Increased biodegradation of LDPE-matrix in starch-filled LDPE materials1992Inngår i: Materials Science and Engineering, Vol. 67, s. 296-297Artikkel i tidsskrift (Fagfellevurdert)
  • 34. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Macromolecular architecture-nature as model for degradable polymers1996Inngår i: Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, Vol. 33, nr 10, s. 1565-1570Artikkel i tidsskrift (Fagfellevurdert)
  • 35. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    New tools for analyzing degradation1995Inngår i: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 98, nr 35th IUPAC International Symposium on Macromolecules, 1995, s. 797-801Artikkel i tidsskrift (Fagfellevurdert)
  • 36. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Polyethylene degradation and degradation products1990Inngår i: Agricultural and Synthetic Polymers: Biodegradability and Utilization, American Chemical Society (ACS), 1990, Vol. 433, nr Agricultural & Synthetic Polymers, s. 60-64Kapittel i bok, del av antologi (Fagfellevurdert)
  • 37. Albertsson, A-C.
    et al.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    The Influence of Biotic and Abiotic Environments on the Degradation of Polyethylene.1990Inngår i: Progress in polymer science, ISSN 0079-6700, E-ISSN 1873-1619, Vol. 15, nr 2, s. 177-192Artikkel i tidsskrift (Fagfellevurdert)
  • 38. Albertsson, A-C.
    et al.
    Sares, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Increased biodegradation of low-density polyethylene (LDPE) with nonionic surfactant1993Inngår i: Acta Polymerica, ISSN 0323-7648, E-ISSN 1521-4044, Vol. 44, nr 5, s. 243-246Artikkel i tidsskrift (Fagfellevurdert)
  • 39.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Frontiers in Biomacromolecules: Functional Materials from Nature2012Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 13, nr 12, s. 3901-3901Artikkel i tidsskrift (Annet vitenskapelig)
  • 40.
    Albertsson, Ann-Christine
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Micro- and macromolecular design of aliphatic polyesters2015Inngår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikkel i tidsskrift (Annet vitenskapelig)
  • 41.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Barrier layers for packaging laminates and packaging laminates comprising such barrier layers2009Patent (Annet (populærvitenskap, debatt, mm))
  • 42.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Erlandsson, Bengt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Molecular weight changes and polymeric matrix changes correlated with the formation of degradation products in biodegraded polyethylene1999Inngår i: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 64, s. 91-99Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 43.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Groning, M.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Emission of volatiles from polymers - A new approach for understanding polymer degradation2006Inngår i: Journal of Polymers and the Environment, ISSN 1566-2543, E-ISSN 1572-8919, Vol. 14, nr 1, s. 8-13Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 44.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Gröning, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Chromatographic analysis as a tool for predicting material performance2005Inngår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, s. 247-248Artikkel i tidsskrift (Annet vitenskapelig)
  • 45.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Degradable polymers and their interaction with the environment2007Inngår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 223, s. 566-567Artikkel i tidsskrift (Annet vitenskapelig)
  • 46.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Designed to degrade Suitably designed degradable polymers can play a role in reducing plastic waste2017Inngår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 358, nr 6365, s. 872-873Artikkel i tidsskrift (Fagfellevurdert)
  • 47.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Biodegradation and test methods for environmental and biomedical applications of polymers2018Inngår i: Degradable Materials: Perspectives, Issues, and Opportunities, CRC Press , 2018, s. 263-293Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 48.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    The three stages in the degradation of polymers- polyethylene as a model substance1988Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 35, s. 1289-1302Artikkel i tidsskrift (Fagfellevurdert)
  • 49. Albertsson, Ann-Christine
    et al.
    Renstad, Rasmus
    Erlandsson, Bengt
    Eldsäter, Carina
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Effect of processing additives on (bio)degradability of film-blown poly(ε-caprolactone)1998Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 70, nr 1, s. 61-74Artikkel i tidsskrift (Fagfellevurdert)
  • 50.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Varma, Indra Kumari
    Centre for Polymer Science and Engineering, Indian Institute of Technology, New Delhi, India.
    Lochab, Bimlesh
    Materials Research Laboratory, Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Greater Noida, India.
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sahu, Sangeeta
    Materials Research Laboratory, Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Tehsil Dadri, India.
    Kumar, Kamlesh
    Council of Scientific and Industrial Research, Central Scientific Instruments Organization, Chandigarh, India.
    Design and synthesis of different types of poly(lactic acid)/polylactide copolymers2022Inngår i: Poly(lactic acid): Synthesis, Structures, Properties, Processing, Applications, and End of Life, Wiley , 2022, s. 45-71Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

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

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