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  • 1.
    Andersson, Helene
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience. Chalmers University of Technology, Sweden.
    Stading, Mats
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience. Chalmers University of Technology, Sweden.
    Hjärtstam, Johan
    Chalmers University of Technology, Sweden; Astra Zeneca R&D Mölndal, Sweden.
    von Corswant, Christian
    Chalmers University of Technology, Sweden; Astra Zeneca R&D Mölndal, Sweden.
    Larsson, Anette
    Chalmers University of Technology, Sweden.
    Effects of Molecular Weight on Phase Separated Coatings for Controlled Release of Drugs2013In: Annual Transactions of the Nordic Rheology Society, p. 249-Article in journal (Refereed)
    Abstract [en]

    Phase separated films with controlled porosity were made from ethyl cellulose (EC) and 30% w/w hydroxypropyl cellulose (HPC). The molecular weight of EC can be used to modify the mass transfer rate through coatings by effects on microstructure of the film. Processing conditions are, however, affected by the solution rheology, which could influence the film quality when using different molecular weights.

  • 2.
    Belaineh, Dagmawi
    et al.
    Linköping University, Sweden.
    Andreasen, Jens W
    DTU Technical University of Denmark, Denmark.
    Palisaitis, Justinas
    Linköping University, Sweden.
    Malti, Abdellah
    KTH Royal institute of Technology, Sweden.
    Håkansson, Karl
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Wågberg, Lars
    KTH Royal institute of Technology, Sweden.
    Crispin, Xavier
    Linköping university, Sweden.
    Engquist, Isak
    Linköping university, Sweden.
    Berggren, Magnus
    Linköping university, Sweden.
    Controlling the Organization of PEDOT:PSS on Cellulose Structures2019In: ACS Applied Polymer Materials, Vol. 1, no 9, p. 2342-2351Article in journal (Refereed)
    Abstract [en]

    Composites of biopolymers and conducting polymers are emerging as promising candidates for a green technological future and areactively being explored in various applications, such as in energy storage ,bioelectronics, and thermoelectrics. While the device characteristics of these composites have been actively investigated, there is limited knowledge concerning the fundamental intracomponent interactions and the modes of molecular structuring. Here, by use of cellulose and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), it is shown that the chemical and structural makeup of the surfaces of the composite components are critical factors that determine the materials organization at relevant dimensions. AFM, TEM, and GIWAXS measurements show that when mixedwith cellulose nanofibrils, PEDOT:PSS organizes into continuous nanosized beadlike structures with an average diameter of 13 nm on the nanofibrils. In contrast, when PEDOT:PSS is blended with molecular cellulose, a phase-segregated conducting network morphology is reached, with a distinctly relatively lower electric conductivity. These results provide insight into the mechanisms ofPEDOT:PSS crystallization and may have significant implications for the design of conducting biopolymer composites for a vast array of applications.

  • 3.
    Berglin, Mattias
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology. University of Gothenburg, Sweden.
    Cavanagh, Jorunn Pauline
    Amicoat A/S, Norway; UiT The Arctic University of Norway, Norway.
    Caous, Josefin Seth
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology.
    Thakkar, Balmukund Sureshkumar
    Amicoat A/S, Norway.
    Vasquez, Jeddah Marie
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology.
    Stensen, Wenche
    UiT The Arctic University of Norway, Norway.
    Lyvén, Benny
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology.
    Svendsen, John-Sigurd
    Amicoat A/S, Norway; UiT The Arctic University of Norway, Norway.
    Svenson, Johan
    RISE Research Institutes of Sweden, Materials and Production.
    Flexible and Biocompatible Antifouling Polyurethane Surfaces Incorporating Tethered Antimicrobial Peptides through Click Reactions2023In: Macromolecular Bioscience, ISSN 1616-5187, E-ISSN 1616-5195Article in journal (Refereed)
    Abstract [en]

    Efficient, simple antibacterial materials to combat implant-associated infections are much in demand. Herein, the development of polyurethanes, both cross-linked thermoset and flexible and versatile thermoplastic, suitable for “click on demand” attachment of antibacterial compounds enabled via incorporation of an alkyne-containing diol monomer in the polymer backbone, is described. By employing different polyolic polytetrahydrofurans, isocyanates, and chain extenders, a robust and flexible material comparable to commercial thermoplastic polyurethane is prepared. A series of short synthetic antimicrobial peptides are designed, synthesized, and covalently attached in a single coupling step to generate a homogenous coating. The lead material is shown to be biocompatible and does not display any toxicity against either mouse fibroblasts or reconstructed human epidermis according to ISO and OECD guidelines. The repelling performance of the peptide-coated materials is illustrated against colonization and biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis on coated plastic films and finally, on coated commercial central venous catheters employing LIVE/DEAD staining, confocal laser scanning microscopy, and bacterial counts. This study presents the successful development of a versatile and scalable polyurethane with the potential for use in the medical field to reduce the impact of bacterial biofilms. 

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  • 4.
    Carmona, Pierre
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food. Chalmers University of Technology, Sweden.
    Röding, Magnus
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food. Chalmers University of Technology, Sweden.
    Särkkä, Aila
    Chalmers University of Technology, Sweden.
    von Corswant, Christian
    AstraZeneca, Sweden.
    Olsson, Eva
    Chalmers University of Technology, Sweden.
    Loren, Niklas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food. Chalmers University of Technology, Sweden.
    Structure evolution during phase separation in spin-coated ethylcellulose/hydroxypropylcellulose films2021In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 17, no 14, p. 3913-3922Article in journal (Refereed)
    Abstract [en]

    Porous phase-separated films made of ethylcellulose (EC) and hydroxypropylcellulose (HPC) are commonly used for controlled drug release. The structure of these thin films is controlling the drug transport from the core to the surrounding liquids in the stomach or intestine. However, detailed understanding of the time evolution of these porous structures as they are formed remains elusive. In this work, spin-coating, a widely applied technique for making thin uniform polymer films, was used to mimic the industrial manufacturing process. The focus of this work was on understanding the structure evolution of phase-separated spin-coated EC/HPC films. The structure evolution was determined using confocal laser scanning microscopy (CLSM) and image analysis. In particular, we determined the influence of spin-coating parameters and EC : HPC ratio on the final phase-separated structure and the film thickness. The film thickness was determined by profilometry and it influences the ethanol solvent evaporation rate and thereby the phase separation kinetics. The spin speed was varied between 1000 and 10 000 rpm and the ratio of EC : HPC in the polymer blend was varied between 78 : 22 wt% and 40 : 60 wt%. The obtained CLSM micrographs showed phase separated structures, typical for the spinodal decomposition phase separation mechanism. By using confocal laser scanning microscopy combined with Fourier image analysis, we could extract the characteristic length scale of the phase-separated final structure. Varying spin speed and EC : HPC ratio gave us precise control over the characteristic length scale and the thickness of the film. The results showed that the characteristic length scale increases with decreasing spin speed and with increasing HPC ratio. The thickness of the spin-coated film decreases with increasing spin speed. It was found that the relation between film thickness and spin speed followed the Meyerhofer equation with an exponent close to 0.5. Furthermore, good correlations between thickness and spin speed were found for the compositions 22 wt% HPC, 30 wt% HPC and 45 wt% HPC. These findings give a good basis for understanding the mechanisms responsible for the morphology development and increase the possibilities to tailor thin EC/HPC film structures. 

  • 5.
    Chinga-Carrasco, Gary
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Biocomposite Inks for 3D Printing2021In: Bioengineering, E-ISSN 2306-5354, Vol. 8, no 8, article id 102Article in journal (Other academic)
    Abstract [en]

    Three-dimensional (3D) printing has evolved massively during the last years and is demonstrating its potential in tissue engineering, wound dressings, cell culture models for drug testing, and prosthesis, to name a few [...]

  • 6.
    Chiulan, Ioana
    et al.
    The National Institute for Research and Development in Chemistry and Petrochemistry, Romania; Advanced Polymer Materials Group, University Politehnica of Bucharest, Romania.
    Heggset, Ellinor B
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Voicu, Stefan
    Chinga-Carrasco, Gary
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Photopolymerization of Bio-Based Polymers in a Biomedical Engineering Perspective2021In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 22, no 5, p. 1795-1814Article in journal (Refereed)
    Abstract [en]

    Photopolymerization is an effective method to covalently cross-link polymer chains that can be shaped into several biomedical products and devices. Additionally, polymerization reaction may induce a fluid-solid phase transformation under physiological conditions and is ideal for in vivo cross-linking of injectable polymers. The photoinitiator is a key ingredient able to absorb the energy at a specific light wavelength and create radicals that convert the liquid monomer solution into polymers. The combination of photopolymerizable polymers, containing appropriate photoinitiators, and effective curing based on dedicated light sources offers the possibility to implement photopolymerization technology in 3D bioprinting systems. Hence, cell-laden structures with high cell viability and proliferation, high accuracy in production, and good control of scaffold geometry can be biofabricated. In this review, we provide an overview of photopolymerization technology, focusing our efforts on natural polymers, the chemistry involved, and their combination with appropriate photoinitiators to be used within 3D bioprinting and manufacturing of biomedical devices. The reviewed articles showed the impact of different factors that influence the success of the photopolymerization process and the final properties of the cross-linked materials.

  • 7.
    El Seoud, Omar
    et al.
    University of São Paulo, Brazil.
    Jedvert, Kerstin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Kostag, Marc
    University of São Paulo, Brazil.
    Possidonio, Shirley
    UNIFESP, Brazil.
    Cellulose, chitin and silk: the cornerstones of green composites2022In: Emergent Materials, ISSN 2522-5731, Vol. 5, no 3, p. 785-Article in journal (Refereed)
    Abstract [en]

    This overview article is concerned with fabrication and applications of the composites of three major biopolymers, cellulose (Cel), chitin (Chn)/chitosan (Chs), and silk fibroin (SF). A brief discussion of their molecular structures shows that they carry functional groups (-OH, -NH-COCH3, -NH2, -CONH-) whose hydrogen-bonding, and der Waals interactions lead to semi-crystalline structures in the solid phase. There are several classes of solvents that disrupt these interactions, hence dissolve the above-mentioned biopolymers. These include solutions of inorganic and organic electrolytes in dipolar aprotic solvents (DASs), ionic liquids (ILs), and their solutions in DASs. Mixing of biopolymer solutions leads to efficient mutual interactions, hence formation of relatively homogeneous composites. These are then regenerated in non-solvents (water, ethanol, acetone) in different physical forms, e.g., fibers, nanoparticles and films. We discuss the fabrication of these products that have enormous potential use in the textile industry, in medicine, in the food industry, and decontamination of fluids. These applications will most certainly expand due to the attractive characteristics of these composites (renewability, sustainability, biodegradation) and the increased public concern about the adverse environmental impact of petroleum-based polymers, as recently shown by the presence of microplastics in air, water, land, and food (Akdogan & Guven in Environ Pollut. 254:113011 (2019)).

  • 8.
    Eriksson, Viktor
    et al.
    Chalmers university of Technology, Sweden.
    Beckerman, Leyla
    Chalmers university of Technology, Sweden.
    Aerts, Erik
    Chalmers university of Technology, Sweden.
    Andersson Trojer, Markus
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Evenäs, Lars
    Chalmers university of Technology, Sweden.
    Polyanhydride Microcapsules Exhibiting a Sharp pH Transition at Physiological Conditions for Instantaneous Triggered Release2023In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 39, no 49, p. 18003-18010Article in journal (Refereed)
    Abstract [en]

    Stimulus-responsive microcapsules pose an opportunity to achieve controlled release of the entire load instantaneously upon exposure to an external stimulus. Core-shell microcapsules based on the polyanhydride poly(bis(2-carboxyphenyl)adipate) as a shell were formulated in this work to encapsulate the model active substance pyrene and enable a pH-controlled triggered release. A remarkably narrow triggering pH interval was found where a change in pH from 6.4 to 6.9 allowed for release of the entire core content within seconds. The degradation kinetics of the shell were measured by both spectrophotometric detection of degradation products and mass changes by quartz crystal microbalance with dissipation monitoring and were found to correlate excellently with diffusion coefficients fitted to release measurements at varying pH values. The microcapsules presented in this work allow for an almost instantaneous triggered release even under mild conditions, thanks to the designed core-shell morphology. 

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  • 9.
    Granlund, Marcus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Kärnkraftsindustrin lär mer om åldring av polymerer2016In: EnerginyheterArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Under hösten samlade Energiforsks seminarium “Ageing of Polymers in nuclear applications – Education and workshop” över 35 personer från 5 olika länder för att lära och diskutera åldring av polymerer inom kärnkraft.

  • 10.
    Gårdebjer, Sofie
    et al.
    Chalmers University of Technology, Sweden.
    Andersson, M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science.
    Engström, J.
    AkzoNobel, Sweden.
    Restorp, P.
    AkzoNobel, Sweden.
    Persson, Michael
    Chalmers University of Technology, Sweden; AkzoNobel, Sweden.
    Larsson, Anette
    Chalmers University of Technology, Sweden.
    Using Hansen solubility parameters to predict the dispersion of nano-particles in polymeric films2016In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 7, no 9, p. 1756-1764Article in journal (Refereed)
    Abstract [en]

    We suggest a rough and straightforward method to predict the dispersibility of modified cellulose nanocrystals (CNC) in nanocomposites using Hansen solubility parameters (HSP). The surface of CNC was modified using a novel approach where Y-shaped substituents with two different carbon chain lengths were attached to the surface. Approximate HSP values were calculated for the modified CNC, and dispersions of unmodified and modified CNC in solvents with varying HSPs were studied. The best dispersibility was observed in dichloromethane, when the CNC surface was modified with longer carbon chains. Dichloromethane has HSP similar to low-density polyethylene (LDPE). Nanocomposites with both unmodified and modified CNC were produced. The materials with modified CNC showed increased adhesion between the filler and the matrix, followed by a decreased water permeability compared to unmodified CNC, suggesting a better dispersibility of modified CNC in LDPE and confirming the usefulness of this approach.

  • 11.
    Hellström, Anna-Karin
    et al.
    Chalmers University of Technology, Sweden.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden (2017-2019), Bioeconomy, Biorefinery and Energy.
    Syrén, Marie
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Chemistry and Materials.
    Nordstierna, Lars
    Chalmers University of Technology, Sweden.
    Bordes, Romain
    Chalmers University of Technology, Sweden.
    Enabling Textile Recycling: On/Off Dyeing2016Conference paper (Other academic)
    Abstract [en]

    Develop a novel family of environmental friendly dispersant for textile coloring embedded an on/off function for closed loop recycling.

  • 12.
    Heydari, Golrokh
    et al.
    KTH Royal Institute of Technology, Sweden.
    Tyrode, Erik
    KTH Royal Institute of Technology, Sweden.
    Visnevskij, Ceslav
    Vilnius University, Lithuania.
    Makuska, Ricardas
    Vilnius University, Lithuania.
    Claesson, Per M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik. KTH Royal Institute of Technology, Sweden.
    Temperature-dependent deicing properties of electrostatically anchored branched brush layers of poly(ethylene oxide)2016In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 17, p. 4194-4202Article in journal (Refereed)
    Abstract [en]

    The hydration water of hydrophilic polymers freezes at subzero temperatures. The adsorption of such polymers will result in a hydrophilic surface layer that strongly binds water. Provided this interfacial hydration water remains liquidlike at subzero temperatures, its presence could possibly reduce ice adhesion, in particular, if the liquidlike layer is thicker than or comparable to the surface roughness. To explore this idea, a diblock copolymer, having one branched bottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. The shear ice adhesion strength on such polymer-coated surfaces was investigated down to -25 °C using a homebuilt device. In addition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branched bottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, at temperatures above -15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer. Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of water interacting with branched and linear poly(ethylene oxide) (with hydration water melting points of about -18 and -10 °C, respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branched bottle-brush structured poly(ethylene oxide) at -10 °C, whereas no significant adhesion reduction was obtained with linear poly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottle-brush structured poly(ethylene oxide), which, in the bulk, does not freeze until -18 °C.

  • 13.
    Jakubowicz, Ignacy
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Skrifvars, Mikael
    Åkesson, Dan
    Boldizar, Antal
    Yarahmadi, Nazdaneh
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi.
    Enebro, Jonas
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Berlin, Johanna
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi.
    Royne, Frida
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energi och Bioekonomi.
    Ericson, Mats
    Svensson, Mats
    Lindgren, Martina
    Guide för bioplaster: från tillverkning till återvinning2016Report (Other academic)
  • 14.
    Javed, Asif
    et al.
    Karlstad University, Sweden.
    Ullsten, Henrik
    Karlstad University, Sweden.
    Ernstsson, Marie
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik.
    Järnström, Lars
    Karlstad University, Sweden.
    Study of starch and starch-PVOH blends and effects of plasticizers on mechanical and barrier properties of coated paperboard2016In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 31, no 3, p. 499-510Article in journal (Refereed)
    Abstract [en]

    The mechanical properties of self-supporting films based on starch-plasticizer and starch-PVOH-plasticizer and the barrier properties of paperboard coated with solutions of these polymers have been studied. The plasticizers used were glycerol, polyethylene glycol and citric acid. It was shown that the addition of a plasticizer and PVOH to starch substantially increases the flexibility of starch films. It was seen that curing the self-supporting films led to a decrease in flexibility. After heat-treatment, a substantial increase in storage modulus was observed only in the starch-PVOH-citric-acid blend films. Tensile tests on the films indicate that citric acid did not cause any noticeable phase separation. Citric acid acted as a compatibilizer for starch-PVOH blends even though a similar enrichment of PVOH at the air-solid interface was observed with both citric acid and polyethylene glycol as plasticizer. The properties of barrier coatings greatly reflected the compatibility of starch-PVOH blends containing citric acid. The only plasticizer that resulted in a lower water vapour transmission rate through the starch and starch-PVOH coatings was citric acid, which suggests that cross-linking took place. With four layers, coatings based of starch-PVOH possessed the same oxygen- transmission rate with citric acid as without citric acid.

  • 15.
    Jönsson, Christina
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology.
    Wei, Ren
    University of Greifswald, Germany.
    Biundo, Antonino
    KTH Royal Institute of Technology, Sweden; REWOW srl, Italy.
    Landberg, Johan
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Schwarz Bour, Lisa
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology.
    Pezzotti, Fabio
    RISE Research Institutes of Sweden, Materials and Production, Manufacturing Processes.
    Toca, Andreea
    Swedish Stockings, Sweden; Hyper Island, Sweden.
    Jacques, Les
    LYCRA Company, UK.
    Bornscheuer, Uwe
    University of Greifswald, Germany.
    Syrén, Per-Olof
    KTH Royal Institute of Technology, Sweden.
    Biocatalysis in the Recycling Landscape for Synthetic Polymers and Plastics towards Circular Textiles2021In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 14, no 19, p. 4028-Article in journal (Refereed)
    Abstract [en]

    Although recovery of fibers from used textiles with retained material quality is desired, separation of individual components from polymer blends used in today's complex textile materials is currently not available at viable scale. Biotechnology could provide a solution to this pressing problem by enabling selective depolymerization of recyclable fibers of natural and synthetic origin, to isolate constituents or even recover monomers. We compiled experimental data for biocatalytic polymer degradation with a focus on synthetic polymers with hydrolysable links and calculated conversion rates to explore this path The analysis emphasizes that we urgently need major research efforts: beyond cellulose-based fibers, biotechnological-assisted depolymerization of plastics so far only works for polyethylene terephthalate, with degradation of a few other relevant synthetic polymer chains being reported. In contrast, by analyzing market data and emerging trends for synthetic fibers in the textile industry, in combination with numbers from used garment collection and sorting plants, it was shown that the use of difficult-to-recycle blended materials is rapidly growing. If the lack of recycling technology and production trend for fiber blends remains, a volume of more than 3400 Mt of waste will have been accumulated by 2030. This work highlights the urgent need to transform the textile industry from a biocatalytic perspective.

  • 16.
    Li, Dongfang
    et al.
    KTH Royal Institute of Technology, Sweden.
    Iversen, Tommy
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Ek, Monica
    KTH Royal Institute of Technology, Sweden.
    Hydrophobic materials based on cotton linter cellulose and an epoxy-activated polyester derived from a suberin monomer2015In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 69, no 6, p. 721-730Article in journal (Refereed)
    Abstract [en]

    Suberin is a natural hydrophobic material that could be used to improve the water repellency of cellulose surfaces. It is also abundant in the outer bark of birch (Betula verrucosa); birch bark is a side-stream product in Scandinavia from the forest industry, which is generally burned for energy production. A suberin monomer, cis-9,10-epoxy-18-hydroxyoctadecanoic acid, was isolated from birch outer bark and polymerized via lipase (immobilized Candida antarctica lipase B). The resulting epoxy-activated polyester was characterized by nuclear magnetic resonance (NMR) imaging, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, and size exclusion chromatography. Then the polyester was cured with tartaric or oxalic acid, and the crosslinked polyesters were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry. Hydrophobic materials were prepared by compression molding of polyester-impregnated cellulose sheets, and the final products were characterized by FTIR, cross-polarization magic angle spinning 13C NMR, and field-emission scanning electron microscopy. The water contact angle was significantly increased from 0° for the original cellulose sheets to over 100° for the produced hydrophobic materials.

  • 17.
    Li, Dongfang
    et al.
    KTH Royal Institute of Technology, Sweden.
    Iversen, Tommy
    RISE, Innventia. KTH Royal Institute of Technology, Sweden.
    Ek, Monica
    KTH Royal Institute of Technology, Sweden.
    Treatment of a cellulose fiber surface with a suberin monomer-derived polymer2015In: Polymers from Renewable Resources, ISSN 2041-2479, Vol. 6, no 3, p. 75-90Article in journal (Refereed)
    Abstract [en]

    The biorefinery concept requires the development of value-added products, such as materials from biomass, including bark. Suberin is the most abundant component in birch (Betula verrucosa) outer bark and acts as a barrier against the penetration of water and external attacks from microorganisms. The aliphatic domain of suberin is rich in hydroxy fatty acids, such as cis-9,10-epoxy-18- hydroxyoctadecanoic acid. In this study, it was isolated from the outer bark of birch and polymerized to prepare polyepoxy acid (PEA), which was used to impregnate filter papers. After complete drying, PEA-loaded filter papers were placed under UV to crosslink the epoxides through cationic polymerization with a diaryliodonium salt as the photo-initiator. The crosslinking was evaluated using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The materials obtained after UV curing showed substantially increased hydrophobicity, decreased moisture absorption, increased tensile strength, and increased ductility. Field-emission scanning electron microscopy (FE-SEM) showed that the crosslinked PEA covered the surface of the cellulose fibers and filled the interstitial spaces.

  • 18.
    Määttänen, Marjo
    et al.
    VTT Technical Research Centre of Finland, Finland.
    Gunnarsson, Maria
    RISE Research Institutes of Sweden, Bioeconomy and Health.
    Wedin, Helena
    RISE Research Institutes of Sweden, Bioeconomy and Health.
    Stibing, Sara
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Olsson, Carina
    RISE Research Institutes of Sweden.
    Köhnke, Tobias
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Asikainen, Sari
    VTT Technical Research Centre of Finland, Finland; Fortum Power and Heat Oy, Finland.
    Vehviläinen, Marianna
    VTT Technical Research Centre of Finland, Finland.
    Harlin, Ali
    VTT Technical Research Centre of Finland, Finland.
    Pre-treatments of pre-consumer cotton-based textile waste for production of textile fibres in the cold NaOH(aq) and cellulose carbamate processes2021In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 28, p. 3869-3886Article in journal (Refereed)
    Abstract [en]

    Recycling of textiles is of importance due to the large amount of waste generated from  the increasing consumption and use worldwide. Cotton-rich pre-consumer textiles are  considered as potential raw material for production of man-made regenerated fibres, but demands purification from the blends with synthetic fibres as well as the dyes and  finishing chemicals. In this study we explore the use of different pre-treatments of pre-consumer textiles to meet specific parameters for production of fibres in the cold  NaOH(aq) or cellulose carbamate process. The pre-treatments consisted of different  bleaching sequences and were performed on both uncoloured and coloured pre-consumer textiles. For the uncoloured textile, degree of polymerisation and amount of  inorganic content was efficiently reduced making the material suitable for both the cold  NaOH(aq) and the cellulose carbamate process. In case of the coloured textile, the pre-treatments were able to remove the dye and decrease the inorganic content as well as  reduce the degree of polymerisation but only sufficiently enough for production of fibres  in the cellulose carbamate process. The work was able to prove a fibre-to-fibre concept  while further optimisation of the regeneration steps is expected to improve the  mechanical properties of the produced fibres in future studies.

  • 19.
    Nechyporchuk, Oleksandr
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Hanna, Ulmefors
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Teleman, Anita
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Silica-rich regenerated cellulose fibers enabled by delayed dissolution of silica nanoparticles in strong alkali using zinc oxide2021In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 264, article id 118032Article in journal (Refereed)
    Abstract [en]

    Silica nanoparticles (SNPs) dissolve in alkaline media, which limits their use in certain applications. Here, we report a delayed dissolution of SNPs in strong alkali induced by zinc oxide (ZnO), an additive which also limits gelation of alkaline cellulose solutions. This allows incorporating high solid content of silica (30 wt%) in cellulose solutions with retention of their predominant viscous behavior long enough (ca. 180 min) to enable fiber wet spinning. We show that without addition of ZnO, silica dissolves completely, resulting in strong gelation of cellulose solutions that become unsuitable for wet spinning. With an increase of silica concentration, gelation of the solutions occurs faster. Employing ZnO, silica-rich regenerated cellulose fibers were successfully spun, possessing uniform cross sections and smooth surface structure without defects. These findings are useful in advancing the development of functional man-made cellulose fibers with incorporated silica, e.g., fibers with flame retardant or self-cleaning properties. © 2021 The Author(s)

  • 20.
    Newson, William R.
    et al.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Kuktaite, Ramune
    SLU Swedish University of Agricultural Sciences, Sweden.
    Hedenqvist, Mikael Stefan
    KTH Royal Institute of Technology, Sweden.
    Gällstedt, Mikael
    RISE, Innventia.
    Johansson, Eva
    SLU Swedish University of Agricultural Sciences, Sweden.
    Effect of additives on the tensile performance and protein solubility of industrial oilseed residual based plastics2014In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 62, no 28, p. 6707-6715Article in journal (Refereed)
    Abstract [en]

    Ten chemical additives were selected from the literature for their proposed modifying activity in protein-protein interactions. These consisted of acids, bases, reducing agents, and denaturants and were added to residual deoiled meals of Crambe abyssinica (crambe) and Brassica carinata (carinata) to modify the properties of plastics produced through hot compression molding at 130 °C. The films produced were examined for tensile properties, protein solubility, molecular weight distribution, and water absorption. Of the additives tested, NaOH had the greatest positive effect on tensile properties, with increases of 105% in maximum stress and 200% in strain at maximum stress for crambe and a 70% increase in strain at maximum stress for carinata. Stiffness was not increased by any of the applied additives. Changes in tensile strength and elongation for crambe and elongation for carinata were related to changes in protein solubility. Increased pH was the most successful in improving the protein aggregation and mechanical properties within the complex chemistry of residual oilseed meals.

  • 21.
    Oguzlu, Hale
    et al.
    University of Alberta, Canada.
    Dobyrden, Illia
    KTH Royal Institute of Technology, Sweden.
    Liu, Xiaoyan
    Shaanxi Normal University, China.
    Bhaduri, Swayamdipta
    University of Alberta, Canada.
    Claesson, Per M
    RISE Research Institutes of Sweden, Bioeconomy and Health. KTH Royal Institute of Technology, Sweden.
    Boluk, Yaman
    University of Alberta, Canada.
    Polymer Induced Gelation of Aqueous Suspensions of Cellulose Nanocrystals2021In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 37, no 10, p. 3015-3024Article in journal (Refereed)
    Abstract [en]

    We investigated the gelation of cellulose nanocrystals (CNCs) in polyelectrolyte and neutral polymer solutions. Cellulose nanocrystals (CNCs) with half-ester sulfate groups produced by acid hydrolysis of wood pulp were used in this study. The microstructure of CNCs/polymer suspensions was investigated in semidilute concentration regimes by selecting carboxymethyl cellulose (CMC700) as an anionic polymer and poly(ethylene oxide) (PEO600) as a neutral polymer solution. Together with quartz crystal microbalance with dissipation monitoring (QCM-D), rheology, scanning electron microscopy (SEM), and cryo-transmission electron microscopy (cryo-TEM), we characterized CNCs-polymer interactions, the suspension microstructure, and the macroscopic gel flow. Significant viscosity increases at low shear rates coupled with high shear-thinning behaviors were observed in CNC colloid-CMC700 polymer mixtures, but not those CNCs in PEO600 solutions. The apparent differences between CNCs-CMC700 and CNCs-PEO600 mixtures were due to their chain confirmations. On the basis of the evaluations from STEM, cryo-TEM, and polarized optical microscopy, we proposed that the excess CMC700 molecules in solutions result in the depletion of CNCs and the formation of anisotropic domains.

  • 22.
    Palme, Anna
    et al.
    Chalmers University of Technology, Sweden.
    Peterson, Anna
    Chalmers University of Technology, Sweden.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Theliander, Hans
    Chalmers University of Technology, Sweden.
    Brelid, Harald
    Södra Innovation, Sweden..
    Development of an efficient route for combined recycling of PET and cotton from mixed fabrics2017In: Textiles and Clothing Sustainability, ISSN 2197-9936, Vol. 3, no 4Article in journal (Refereed)
    Abstract [en]

    Most textile waste is either incinerated or landfilled today, yet, the material could instead be recycled through chemical recycling to new high-quality textiles. A first important step is separation since chemical recycling of textiles requires pure streams. The focus of this paper is on the separation of cotton and PET (poly(ethylene terephthalate), polyester) from mixed textiles, so called polycotton. Polycotton is one of the most common materials in service textiles used in sheets and towels at hospitals and hotels. A straightforward process using 5–15 wt% NaOH in water and temperature in the range between 70 and 90 °C for the hydrolysis of PET was evaluated on the lab-scale. In the process, the PET was degraded to terephthalic acid (TPA) and ethylene glycol (EG). Three product streams were generated from the process. First is the cotton; second, the TPA; and, third, the filtrate containing EG and the process chemicals. The end products and the extent of PET degradation were characterized using light microscopy, UV-spectroscopy, and ATR FT-IR spectroscopy, as well as solution and solid-state NMR spectroscopy. Furthermore, the cotton cellulose degradation was evaluated by analyzing the intrinsic viscosity of the cotton cellulose. The findings show that with the addition of a phase transfer catalyst (benzyltributylammonium chloride (BTBAC)), PET hydrolysis in 10% NaOH solution at 90 °C can be completed within 40 min. Analysis of the degraded PET with NMR spectroscopy showed that no contaminants remained in the recovered TPA, and that the filtrate mainly contained EG and BTBAC (when added). The yield of the cotton cellulose was high, up to 97%, depending on how long the samples were treated. The findings also showed that the separation can be performed without the phase transfer catalyst; however, this requires longer treatment times, which results in more cellulose degradation.

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  • 23.
    Ribul, Miriam
    et al.
    University of the Arts London, UK.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    The Material Affinity of Design and Science for a Circular Economy2016In: Circular Transitions Proceedings, 2016, p. 236-248Conference paper (Refereed)
    Abstract [en]

    This paper presents a design and material science collaboration in a science laboratory for regenerated cellulose. The material affinity outlines how both disciplines are connected through a materials practice in communication and production of cellulose films. The outcome presents new transdisciplinary approaches for design and science towards circularity of materials.

  • 24.
    Röding, Magnus
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Agrifood and Bioscience.
    Gaska, Karolina
    Chalmers University of Technology, Sweden .
    Kádár, Roland
    Chalmers University of Technology, Sweden.
    Loren, Niklas
    Chalmers University of Technology, Sweden.
    Computational Screening of Diffusive Transport in Nanoplatelet-Filled Composites: Use of Graphene To Enhance Polymer Barrier Properties2017In: ACS Applied Nano Materials, ISSN 2574-0970, Vol. 1, no 1, p. 160-167Article in journal (Refereed)
    Abstract [en]

    Motivated by the substantial interest in various fillers to enhance the barrier properties of polymeric films, especially graphene derivatives, we perform a computational screening of obstructed diffusion to explore the design parameter space of nanoplatelet-filled composites synthesized in silico. As a model for the nanoplatelets, we use circular and elliptical nonoverlapping and impermeable flat disks, and diffusion is stochastically simulated using a random-walk model, from which the effective diffusivity is calculated. On the basis of ∼1000 generated structures and diffusion simulations, we systematically investigate the impact of different nanoplatelet characteristics such as orientation, layering, size, polydispersity, shape, and amount. We conclude that the orientation, size, and amount of nanoplatelets are the most important parameters and show that using nanoplatelets oriented perpendicular to the diffusion direction, under reasonable assumptions, with approximately 0.2% (w/w) graphene, we can reach 90% reduction and, with approximately 1% (w/w) graphene, we can reach 99% reduction in diffusivity, purely because of geometrical effects, in a defect-free matrix with perfect compatibility. Additionally, our results suggest that the existing analytical models have some difficulty with extremely large aspect ratio (extremely flat) nanoplatelets, which calls for further development.

  • 25.
    Shen, Zhiqiang
    et al.
    University of Connecticut, USA.
    Röding, Magnus
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience. University College London, Australia.
    Kröger, Martin
    ETH Zürich, Switzerland.
    Li, Ying
    University of Connecticut, USA .
    Carbon nanotube length governs the viscoelasticity and permeability of buckypaper2017In: Polymers, E-ISSN 2073-4360, Vol. 9, no 4, article id 115Article in journal (Refereed)
  • 26.
    Skärberg, Fredrik
    et al.
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food.
    Fager, Cecilia
    Chalmers University of Technology, Sweden; KTH Royal Institute of Technology, Sweden.
    Mendoza-Lara, Francisco
    Josefson, Mats
    AstraZeneca, Sweden.
    Olsson, Eva
    Chalmers University of Technology, Sweden.
    Loren, Niklas
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food. Chalmers University of Technology, Sweden.
    Röding, Magnus
    RISE Research Institutes of Sweden, Bioeconomy and Health, Agriculture and Food. Chalmers University of Technology, Sweden; University of Gothenburg, Sweden.
    Convolutional neural networks for segmentation of FIB-SEM nanotomography data from porous polymer films for controlled drug release2021In: Journal of Microscopy, ISSN 0022-2720, E-ISSN 1365-2818, Vol. 283, no 1, p. 51-63Article in journal (Refereed)
    Abstract [en]

    Phase-separated polymer films are commonly used as coatings around pharmaceutical oral dosage forms (tablets or pellets) to facilitate controlled drug release. A typical choice is to use ethyl cellulose and hydroxypropyl cellulose (EC/HPC) polymer blends. When an EC/HPC film is in contact with water, the leaching out of the water-soluble HPC phase produces an EC film with a porous network through which the drug is transported. The drug release can be tailored by controlling the structure of this porous network. Imaging and characterization of such EC porous films facilitates understanding of how to control and tailor film formation and ultimately drug release. Combined focused ion beam and scanning electron microscope (FIB-SEM) tomography is a well-established technique for high-resolution imaging, and suitable for this application. However, for segmenting image data, in this case to correctly identify the porous network, FIB-SEM is a challenging technique to work with. In this work, we implement convolutional neural networks for segmentation of FIB-SEM image data. The data are acquired from three EC porous films where the HPC phases have been leached out. The three data sets have varying porosities in a range of interest for controlled drug release applications. We demonstrate very good agreement with manual segmentations. In particular, we demonstrate an improvement in comparison to previous work on the same data sets that utilized a random forest classifier trained on Gaussian scale-space features. Finally, we facilitate further development of FIB-SEM segmentation methods by making the data and software used open access. © 2021 The Authors.

  • 27.
    Stamm, Arne
    et al.
    KTH Royal Institute of Technology, Sweden.
    Oehlin, Johannes
    KTH Royal Institute of Technology, Sweden.
    Mosbech, Caroline
    KTH Royal Institute of Technology, Sweden.
    Olsen, Peter
    KTH Royal Institute of Technology, Sweden.
    Guo, Boyang
    KTH Royal Institute of Technology, Sweden.
    Söderberg, Elisabeth
    KTH Royal Institute of Technology, Sweden.
    Biundo, Antonino
    KTH Royal Institute of Technology, Sweden.
    Fogelström, Linda
    KTH Royal Institute of Technology, Sweden.
    Bhattacharyya, Shubhankar
    RISE Research Institutes of Sweden, Bioeconomy and Health, Biorefinery and Energy.
    Bornscheuer, Uwe T.
    University of Greifswald, Germany.
    Malmström, Eva
    KTH Royal Institute of Technology, Sweden.
    Syren, Per-Olof
    KTH Royal Institute of Technology, Sweden.
    Pinene-based oxidative synthetic toolbox for scalable polyester synthesis2021In: JACS Au, E-ISSN 2691-3704, Vol. 1, no 11, p. 1949-1960Article in journal (Refereed)
    Abstract [en]

    Generation of renewable polymers is a long-standing goal toward reaching a more sustainable society . Herein we show how conceptually simple oxidative transformations can be used to unlock the inherent reactivity of terpene synthons in generating polyesters by two different mechanisms starting from the same α-pinene substrate. In the first pathway, α-pinene was oxidized into the bicyclic verbanone based lactone (VaL) and subsequently polymerized into star-shaped polymers via ring-opening polymerization, resulting in a biobased semicrystalline polyester with tunable glass transition and melting temperatures In a second pathway, polyesters were synthesized via polycondensation, utilizing the diol (1-(1'-hydroxyethyl)-3-(2'-hydroxyethyl)-2,2-dimethylcyclobutane (HHDC)) synthesized by oxidative cleavage of the double bond of α-pinene, together with unsaturated biobased diesters such as di-Me maleate (DMM) and di-Me itaconate (DMI), resp. The resulting families of terpene-based polyesters were thereafter successfully crosslinked by either transetherification, utilizing the terminal hydroxyl groups of the synthesized verbanone-based materials, or by UV-irradiation, utilizing the unsaturation provided by the DMM or DMI moieties within the HHDC-based copolymers. This work highlights the potential to apply an oxidative toolbox to valorize inert terpene metabolites enabling generation of bio sourced polyesters and coatings thereof by complementary mechanisms.

  • 28.
    Svagan, Anna J.
    et al.
    KTH Royal Institute of Technology, Sweden; University of Copenhagen, Denmark.
    Benjamins, Jan-Willem
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science.
    Al-Ansari, Zeinab
    University of Copenhagen, Denmark.
    Shalom, Daniel Bar
    University of Copenhagen, Denmark.
    Müllertz, Anette
    University of Copenhagen, Denmark.
    Wågberg, Lars
    KTH Royal Institute of Technology, Sweden.
    Löbmann, Korbinian
    University of Copenhagen, Denmark.
    Solid cellulose nanofiber based foams – Towards facile design of sustained drug delivery systems2016In: Journal of Controlled Release, ISSN 0168-3659, E-ISSN 1873-4995, Vol. 244, p. 74-82Article in journal (Refereed)
    Abstract [en]

    Control of drug action through formulation is a vital and very challenging topic within pharmaceutical sciences. Cellulose nanofibers (CNF) are an excipient candidate in pharmaceutical formulations that could be used to easily optimize drug delivery rates. CNF has interesting physico-chemical properties that, when combined with surfactants, can be used to create very stable air bubbles and dry foams. Utilizing this inherent property, it is possible to modify the release kinetics of the model drug riboflavin in a facile way. Wet foams were prepared using cationic CNF and a pharmaceutically acceptable surfactant (lauric acid sodium salt). The drug was suspended in the wet-stable foams followed by a drying step to obtain dry foams. Flexible cellular solid materials of different thicknesses, shapes and drug loadings (up to 50 wt%) could successfully be prepared. The drug was released from the solid foams in a diffusion-controlled, sustained manner due to the presence of intact air bubbles which imparted a tortuous diffusion path. The diffusion coefficient was assessed using Franz cells and shown to be more than one order of magnitude smaller for the cellular solids compared to the bubble-free films in the wet state. By changing the dimensions of dry foams while keeping drug load and total weight constant, the drug release kinetics could be modified, e.g. a rectangular box-shaped foam of 8 mm thickness released only 59% of the drug after 24 h whereas a thinner foam sample (0.6 mm) released 78% of its drug content within 8 h. In comparison, the drug release from films (0.009 mm, with the same total mass and an outer surface area comparable to the thinner foam) was much faster, amounting to 72% of the drug within 1 h. The entrapped air bubbles in the foam also induced positive buoyancy, which is interesting from the perspective of gastroretentive drug-delivery.

  • 29.
    Tuominen, Mikko
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik.
    Funktionella ytbeläggningar på trä/ Functional multilayer coatings to improve properties of wood2016Report (Other academic)
    Abstract [sv]

    Report on the Troëdsson Postdoc-project 2013‒2015.

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  • 30.
    Warlin, Niklas
    et al.
    Lund University, Sweden.
    Nilsson, Erik
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles. Plasman, Sweden.
    Guo, Zengwei
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Mankar, Smita
    Lund University, Sweden.
    Valsange, Nitin
    Lund University, Sweden.
    Rehnberg, Nicola
    Lund University, Sweden; Bona AB, Sweden.
    Lundmark, Stefan
    Perstorp AB. Sweden.
    Jannasch, Patric
    Lund University, Sweden.
    Zhang, Baozhong
    Lund University, Sweden.
    Synthesis and melt-spinning of partly bio-based thermoplastic poly(cycloacetal-urethane)s toward sustainable textiles2021In: Polymer Chemistry, ISSN 1759-9954, E-ISSN 1759-9962, Vol. 12, no 34, p. 4942-4953Article in journal (Refereed)
    Abstract [en]

    A rigid diol with a cyclic acetal structure was synthesized by facile acetalation of fructose-based 5-hydroxymethyl furfural (HMF) and partly bio-based di-trimethylolpropane (di-TMP). This diol (Monomer T) was copolymerized with potentially bio-based flexible polytetrahydrofuran and diisocyanates to prepare thermoplastic poly(cycloacetal-urethane)s. A modified one-step solution polymerization protocol resulted in relatively high molecular weights (Mn ∼ 41.5-98.9 kDa). All the obtained poly(cycloacetal-urethane)s were amorphous with tuneable glass transition temperatures up to 104 °C. Thermogravimetric analysis indicated that these polymers were thermally stable up to 253 °C and had a relatively high pyrolysis char residue, which may indicate potential inherent flame resistance. Melt rheology measurements were performed to determine a suitable processing window between 165-186 °C, after which the polymer was successfully melt-spun into ∼150 meters of homogeneous fibres at 185 °C. The resulting fibres could be readily hydrolysed under acidic conditions, resulting in partial recovery of the original chemical building blocks.

  • 31.
    Wedin, Helena
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Niit, Ellinor
    Swedish School of Textiles, Sweden.
    Ahmad Mansoor, Zaheer
    re:newcell, Sweden.
    Kristinsdottir, Anna Runa
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    de la Motte, Hanna
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Jönsson, Christina
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Östlund, Åsa
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Lindgren, Christofer
    re:newcell, Sweden.
    Investigation of recycled viscose fibres after removal of a reactive dye combination and an easy care finish agent2017Conference paper (Other academic)
    Abstract [en]

    Textile-to-textile recycling from cotton textiles can be done either mechanically or chemically. In chemical textile recycling of cotton there are challenges to overcome in order to regenerate new fibres. Two of the challenges among others are reactive dyes and wrinkle-free finishes that could disturb the regeneration process steps since these finishes are covalently linked to the cellulose.

    This poster discusses the impact of using a novel alkaline/acid bleaching sequence to strip reactive dyes and wrinkle-free finish (DMDHEU) from cotton textile for production of regenerated viscose fibre properties. The results might generate a promising step forward to overcome quality challenges for cellulosic chemical recycling.

  • 32.
    Wei, XF
    et al.
    KTH Royal Institute of Technology, Sweden.
    Hedenqvist, MS
    KTH Royal Institute of Technology, Sweden.
    Zhao, L
    KTH Royal Institute of Technology, Sweden.
    Barth, A
    Stockholm University, Sweden.
    Yin, Haiyan
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Risk for the release of an enormous amount of nanoplastics and microplastics from partially biodegradable polymer blends2022In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 24, p. 8742-8750Article in journal (Refereed)
    Abstract [en]

    Nanoplastics and microplastics (NMPs) in natural environments are an emerging global concern and understanding their formation processes from macro-plastic items during degradation/weathering is critical for predicting their quantities and impacts in different ecological systems. Here, we show the risk of enormous emissions of NMPs from polymer blends, a source that has not been specifically studied, by taking immiscible (most common case) partially biodegradable polymer blends as an example. The blends have the common “sea-island” morphology, where the minor non-biodegradable polymer phase (polyethylene and polypropylene) is dispersed as NMP particles in the major continuous biodegradable matrix (poly(ϵ-caprolactone)). The dispersed NMP particles with spherical and rod-like shapes are gradually liberated and released to the surrounding aquatic environment during the biodegradation of the matrix polymer. Strikingly, the number of released NMPs from the blend is very high. The blend film surface erosion process, induced by enzymatic hydrolysis of the matrix, involving fragmentation, hole formation, and hole wall detachment, was systematically investigated to reveal the NMP release process. Our findings present direct evidence and detailed insights into the high risk of emissions of NMPs from partially biodegradable immiscible polymer blends with a widespread “sea-island” morphology. Efforts from authorities, developers, manufacturers, and the public are needed to avoid the use of non-biodegradable polymers in blends with biodegradable polymers. 

  • 33.
    Yarahmadi, Nazdaneh
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Jakubowicz, Ignacy
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Enebro, Jonas
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Polylactic acid and its blends with petroleum-based resins: Effects of reprocessing and recycling on properties2016In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 133, no 36, article id 43916Article in journal (Refereed)
    Abstract [en]

    Environmental and economic reasons make the use of bioplastics and biocomposites increasingly coveted in sectors other than packaging. Recycling of all wasted or rejected durable plastics is highly desired and biobased plastics are no exception. Therefore, the investigation of pre- and post-consumer recycling of products made from biobased plastics is of great interest. Polylactic acid (PLA) and its blends have been chosen for this study because it is an excellent representative of mass-produced bioplastics for industrial applications. As part of the "Sustainable Recycling of 'Green' Plastics" project, the current study addresses the durability issues related to the reprocessing and post-consumer recycling of a PLA virgin resin and two commercially available blends of PLA namely one with polycarbonate (PC) and one with polyethylene (PE). The materials were investigated using methods that simulate post-processing and post-consumer recycling. Accelerated ageing was performed at elevated temperature and humidity to simulate the usage period of the materials. The materials were analyzed using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and their mechanical strength was evaluated by tensile and impact testing. The flow properties of the materials were characterized by the melt flow index (MFI). Multiple processing of pure PLA did not affect the impact strength or the glass transition temperature (Tg), but caused crystallization and increase in the MFI, indicating that degradation occurred during processing. DSC thermograms of the blends revealed that the components in the blends were not miscible. Multiple processing of the blends did not significantly affect the elastic modulus of the materials, but affected the elongation at break. The results indicated that multiple processing of the PLA/HDPE blend caused increased dispersion and thus increased elongation at break, while the dominating mechanism in the PLA/PC blend was degradation that caused a decrease in elongation at break. Post-consumer recycling of the PLA/PC blend was simulated and the results clearly showed that ageing corresponding to one year of use caused a significant degradation of PLA. Pure PLA was severely degraded after only one ageing cycle. Although the PLA/PC blend showed some improved mechanical properties and resistance to degradation compared with pure PLA, one ageing cycle still caused a severe degradation of the PLA and even the PC was degraded as indicated by the formation of small amounts of bisphenol A.

  • 34.
    Zarna, Chiara
    et al.
    NTNU, Norway.
    Opedal, Mihaela Tanase
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Echtermeyer, Andreas
    NTNU, Norway.
    Chinga-Carrasco, Gary
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Reinforcement ability of lignocellulosic components in biocomposites and their 3D printed applications – A review2021In: Composites Part C: Open Access, ISSN 2666-6820, Vol. 6, article id 100171Article in journal (Refereed)
    Abstract [en]

    Biocomposites based on lignocellulosic components (e.g. pulp fibers, nanocellulose and lignin) are of interest as sustainable replacements for thermoplastic fossil-based materials, which find their application in household items, construction, automotive, 3D-printing, etc. Nanocellulose, a nano-structural component of pulp fibers, is considered having potential as a high-performance reinforcement for bioplastics, due to its high aspect ratio and potentially strong mechanical properties. Lignin, a biodegradable polymer isolated from pulp fibers, can be considered as an essential bioresource for the production of biocomposites, due to the aromatic structure and functional groups. In this review the reinforcing ability of selected lignocellulosic components and their applicability in 3D printing is presented, considering their mechanical properties. At this point, there are challenges in processing nanocellulose that may reduce its attractiveness as a reinforcement in thermoplastic biocomposites. The objective of the review is to identify current challenges and opportunities for the application of 3D printed lignocellulosic biocomposites. Optimization of 3D printing process parameters are considered to be a key to further improve the mechanical properties of the end-product. Importantly, this review revealed that greater efforts in mechanical fatigue research may contribute to assess and improve the potential of lignocellulosic reinforcements for structural applications. © 2021 The Authors

  • 35.
    Åkesson, Dan
    et al.
    University of Boras, Sweden.
    Ramamoorthy, Sunil
    University of Boras, Sweden.
    Bohlén, Martin
    RISE Research Institutes of Sweden, Materials and Production, Polymeric Materials and Composites.
    Skrifvars, Ville-Viktor
    University of Boras, Sweden.
    Svensson, Sofie
    University of Boras, Sweden.
    Skrifvars, Mikael
    University of Boras, Sweden.
    Thermo-oxidative aging of high-density polyethylene reinforced with multiwalled carbon nanotubes2021In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 138, no 26, article id 50609Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the influence of aging on the properties of high-density polyethylene (HDPE) reinforced with multi-wall carbon nanotubes (MWCNTs). Nanocomposites were prepared with nanotubes at 0, 1, 3, and 5 wt%. The long-term durability of the prepared materials was evaluated by thermo-oxidative aging test. Test bodies were aged at 110°C for up to 10 weeks. The nanocomposites were characterized by differential scanning calometry, thermogravimetric analysis (TGA), 13C-NMR, elongation at break, and transmission electron microscopy. The aging mainly occurred on the surface of the samples and the neat HDPE showed a strong yellowing after the aging. A strong reduction in elongation at break was seen. For neat HDPE, the elongation at break was reduced from roughly 1400–25%. When HDPE was reinforced with the nanotubes, the reduction was less dramatic. © 2021 The Authors. 

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