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  • 1. Aguirre, Miren
    et al.
    Johansson Salazar-Sandoval, Eric
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. SP Technical Research Institute of Sweden, Sweden.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ahniyaz, Anwar
    Paulis, Maria
    Ramon Leiza, Jose
    Hybrid acrylic/CeO2 nanocomposites using hydrophilic, spherical and high aspect ratio CeO2 nanoparticles2014In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 2, no 47, p. 20280-20287Article in journal (Refereed)
    Abstract [en]

    A dispersion of CeO2 nanoparticles and nanorods stabilized with nitrilotriacetic acid (NTA) and a 4,4'-azobis(4-cyanovaleric acid) (V-501) initiator has been used to initiate the emulsion polymerization of acrylic monomers, yielding stable hybrid CeO2 nanoparticle-nanorod/polyacrylate latexes for the first time. Films cast from these hybrid latexes are transparent due to the very homogenous distribution of the polymer compatibilized CeO2. Furthermore, it has been proven that the UV-Vis absorption capacity of the hybrid latexes is enhanced with the incorporation of the nanorods.

  • 2.
    Ansari, Farhan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Erik, Lindh
    Furo, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Mats, Johansson
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lars, Berglund
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Interface tailoring through covalent hydroxyl-epoxy bonds improves  hygromechanical stability in nanocellulose materialsManuscript (preprint) (Other academic)
    Abstract [en]

    Wide-spread use of cellulose nanofibril (CNF) biocomposites and nanomaterials is limited by CNF moisture sensitivity due to surface hydration. We report on a versatile and scalable interface tailoring route for CNF to address this, based on technically important epoxide chemistry. Bulk impregnation of epoxide-amine containing liquids is used to show that CNF hydroxyls can react with epoxides at high rates and high degree of conversion to form covalent bonds. Reactions take place inside nanostructured CNF networks under benign conditions, and are verified by solid state NMR. Epoxide modified CNF nanopaper shows significantly improved mechanical properties under moist and wet conditions. High resolution microscopy is used in fractography studies to relate the property differences to structural change. The cellulose-epoxide interface tailoring concept is versatile in that the functionality of molecules with epoxide end-groups can be varied over a wide range. Furthermore, epoxide reactions with nanocellulose can be readily implemented for processing of moisture-stable, tailored interface biocomposites in the form of coatings, adhesives and molded composites.

  • 3.
    Ansari, Farhan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Galland, Sylvain
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Cellulose nanofiber network of high specific surface area provides altered curing reacion and moisture stability in ductile epoxy biocompositesManuscript (preprint) (Other academic)
  • 4.
    Ansari, Farhan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Galland, Sylvain
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Plummer, Christopher J. G.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Cellulose nanofiber network for moisture stable, strong and ductile biocomposites and increased epoxy curing rate2014In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 63, p. 35-44Article in journal (Refereed)
    Abstract [en]

    Nanocomposites with high volume fractions (15-50 vol%) of nanofibrillated cellulose (NFC) were prepared by impregnation of a wet porous NFC network with acetone/epoxy/amine solution. Infrared spectroscopy studies revealed a significant increase in curing rate of epoxy (EP) in the presence of NFC. The NFC provided extremely efficient reinforcement (at 15 vol%: 3-fold increase in stiffness and strength to 5.9 GPa and 109 MPa, respectively), and ductility was preserved. Besides, the glass transition temperature increased with increasing NFC content (from 68 degrees C in neat epoxy to 86 degrees C in 50 vol% composite). Most interestingly, the moisture sorption values were low and even comparable to neat epoxy for the 15 vol% NFC/EP. This material did not change mechanical properties at increased relative humidity (90% RH). Thus, NFC/EP provides a unique combination of high strength, modulus, ductility, and moisture stability for a cellulose-based biocomposite. Effects from nanostructural and interfacial tailoring are discussed.

  • 5.
    Ansari, Farhan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Galland, Sylvain
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Skrivfars, Mikael
    Plummer, Christopher
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Biocomposites of nanofibrillated cellulose with thermoset resins2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, p. 41-CELL-Article in journal (Other academic)
  • 6.
    Ansari, Farhan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites.
    Lindh, Erik L.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Innventia AB, Sweden.
    Furo, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats K.G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Interface tailoring through covalent hydroxyl-epoxy bonds improves hygromechanical stability in nanocellulose materials2016In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 134, p. 175-183Article in journal (Refereed)
    Abstract [en]

    Wide-spread use of cellulose nanofibril (CNF) biocomposites and nanomaterials is limited by CNF moisture sensitivity due to surface hydration. We report on a versatile and scalable interface tailoring route for CNF to address this, based on technically important epoxide chemistry. Bulk impregnation of epoxide-amine containing liquids is used to show that CNF hydroxyls can react with epoxides at high rates and high degree of conversion to form covalent bonds. Reactions take place inside nanostructured CNF networks under benign conditions, and are verified by solid state NMR. Epoxide modified CNF nanopaper shows significantly improved mechanical properties under moist and wet conditions. High resolution microscopy is used in fractography studies to relate the property differences to structural change. The cellulose-epoxide interface tailoring concept is versatile in that the functionality of molecules with epoxide end-groups can be varied over a wide range. Furthermore, epoxide reactions with nanocellulose can be readily implemented for processing of moisture-stable, tailored interface biocomposites in the form of coatings, adhesives and molded composites.

  • 7.
    Antonsson, Stefan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE).
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lindström, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Biomimetic synthesis of suberin for new biomaterials2005In: Appita Annual Conference: Vol 2, 2005, p. 561-564Conference paper (Refereed)
    Abstract [en]

    Suberin is the biopolymer giving cork (oak bark) its hydrophobic and resistant characteristics. It acts as a diffusion barrier in bark and roots of plants. Similarly to lignin, it is a phenolic polymer with good affinity to cellulose and other wood polysaccharides, but it also contains polyaliphatic and strongly hydrophobic elements. In order to produce a lignin derivative similar to suberin, a desired lignin starting material should be of low molecular weight and have a high content of hydroxylic phenolic groups. By means of cross flow nanofiltration of softwood kraft pulping black liquor and pH-precipitation with diluted sulphuric acid, such a lignin has been obtained. Due to the fact that too much organics entering the recovery boiler frequently is the bottleneck for pulp production increases, a removal of part of the lignin can be economically very favourable. By using this lignin together with linola oil, a linseed oil with a large amount of unsaturated structures, an attempt was made to create a new hydrophobic lignin derivative similar tosuberin. The product was analysed with FT-IR, Fourier Transformed Infra Red Spectroscopy and GPC, Gel Permeation Chromatography. The suberin like material obtained from this lignin could be polymerised on thermo mechanical pulp fibres by means of Mn(III)-driven phenolic coupling. The ability of the suberin monomers to act as a hydrophobic paper coating was evaluated with contact angle measurements and the results indicate that this lignin derivative was potentially of interest due to its capability to interact well with wood fibres and make paper hydrophobic.

  • 8.
    Antonsson, Stefan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Henriksson, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Low Mw-lignin fractions together with vegetable oils as available oligomers for novel paper-coating applications as hydrophobic barrier2008In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 27, no 1, p. 98-103Article in journal (Refereed)
    Abstract [en]

    Lignin residues are available in large amounts as kraft lignin from chemical pulping processes. This lignin is mainly incinerated in recovery boilers. The recovery boilers are often the bottle-necks in the overall pulping process when pulp production increases are desired. Through cross-flow nano-filtration of the black liquor from kraft pulping, a low-molecular weight lignin fraction can be removed thus decreasing the organic load on the recovery boilers. The low-molecular weight lignin fraction furthermore exhibit different characteristics compared to other commercial kraft lignins and represents a new raw material source in novel applications.

    The low-molecular weight lignin was used together with a vegetable oil to produce a new hydrophobic lignin derivative similar to suberin. The lignin and the lignin derivative was analysed with FT-IR, UV-vis and SEC. The ability of the product to make paper surfaces hydrophobic was also evaluated.

    The results demonstrate the possibility to make a suberin-like lignin derivative that is potentially of interest in paper-coating applications due to its capability to interact well with wood fibres and make paper hydrophobic.

  • 9. Bexell, U.
    et al.
    Berger, R.
    Olsson, M.
    Grehk, T. M.
    Sundell, P. E.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Bonding of vegetable oils to mercapto silane treated metal surfaces: Surface engineering on the nano scale2006In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, no 2, p. 838-841Article in journal (Refereed)
    Abstract [en]

    In this paper the bonding of thin vegetable oil films on mercapto silane treated aluminium surfaces has been studied. The silane molecules are attached to the surface by metal-oxygen-silicon bonds. The coupling between the unsaturated bonds of the vegetable oil and the thiol functionalised surface was obtained through a photoinduced thiol-ene reaction. The surfaces were characterised by X-ray photoelectron spectroscopy (XPS). Vegetable oil contains both saturated and unsaturated carbon chains. For the reactions investigated in this study it is the unsaturated carbon chains that can react by a thiol-ene reaction and the results indicate that it is possible to attach a vegetable oil to a metal surface pre-treated with a thiol functionalised silane.

  • 10. Bexell, U.
    et al.
    Olsson, M.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Samuelsson, J.
    Sundell, P. E.
    A tribological study of a novel pre-treatment with linseed oil bonded to mercaptosilane treated aluminium2003In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 166, no 03-feb, p. 141-152Article in journal (Refereed)
    Abstract [en]

    In sheet metal forming processes, lubricants are necessary in order to prevent galling, i.e. material transfer from the sheet metal to the tool surface and to control friction. Today, dry lubricants are increasingly being used for solving this problem. Among these, multifunctional coatings, often referred to as permanent coatings, normally based on organic resins, are lubricants which have the potential to increase the formability without additional lubrication, give corrosion protection, fingerprint and scratch resistance during handling and transport and finally, serve as a pre-treatment before painting. With increasing concern about the environment and human health it is important to develop new environmentally friendly pre-treatments in the surface engineering of metal substrates. This is mainly due to the toxic and carcinogenic properties of the chromium based surface pre-treatments frequently used in the industry. During the last decade, simple solution-dip silane based pre-treatments have emerged as promising candidates for the replacement of currently used pre-treatments of metals. A silane film can give good corrosion protection properties but is often too thin to prevent galling under a forming operation. A renewed interest for using vegetable oils in surface engineering has appeared lately due to several factors. Vegetable oils are renewable resources, modem technology can produce more well defined and pure oils, and the fatty acid content can be altered with modern crops development techniques. With the proper choice of silane pre-treatment of a metal surface, a vegetable oil can be coupled to the surface and give the desired lubrication properties. In this paper, aluminium sheets have been pre-treated with a mercapto silane after which a vegetable oil has been attached. The coupling between the silane and the oil was obtained through a photoinduced thiol-ene reaction using UV-radiation. The influence of different process parameters on the friction and wear behaviour was evaluated using modified scratch testing. Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and contact angle measurements were used to characterise the as-deposited surface films and their tribological behaviour, i.e. failure mechanisms. The results obtained show that the unsaturated vegetable oil has reacted with the thiol groups via the thiol-ene reaction forming a surface film. Also, the results show that the thickness of the films is of importance for the tribological characteristics, i.e. a too thin layer (less than 25 A in the present work) results in high friction and severe adhesive wear. However, a thicker layer with enhanced load carrying capacity can be produced with a proper heat treatment of the deposited vegetable oil. Finally, the results show that thick (more than 200 Angstrom in the present work) silane films are sensitive to brittle fracture when exposed to a sliding contact.

  • 11. Bexell, U.
    et al.
    Olsson, M.
    Sundell, P. E.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Carlsson, P.
    Hellsing, A.
    A ToF-SIMS study of linseed oil bonded to mercapto silane treated aluminium2004In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 231-2, p. 362-365Article in journal (Refereed)
    Abstract [en]

    ToF-SIMS has been used to analyse an aluminium surface treated with a vegetable oil using a mercapto silane as a coupling agent between the aluminium substrate and the vegetable oil. The coupling between the vegetable oil and the mercapto silane was obtained through a photoinduced thiol-ene reaction using UV-radiation. The ToF-SIMS results show that the desired thiolene reaction has taken place between the unsaturated parts of the vegetable oil and the thiol groups of the mercapto silane via the thiol-ene reaction forming a surface film.

  • 12.
    Bruce, Carl
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Bionanocomposites reinforcedwith cellulose nanofibrils compatibilized through covalent grafting or physisorption of PCL –a comparative studyManuscript (preprint) (Other academic)
  • 13.
    Brännström, Sara
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Finnveden, Maja
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Itaconate based polyesters: Selectivity and performance of esterification catalysts2018In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 103, p. 370-377Article in journal (Refereed)
    Abstract [en]

    The performance of different esterification catalysts was studied for the use in synthesis of renewable polyesters from dimethyl itaconate (DMI), dimethyl succinate (DMS) and 1,4-butanediol (BD). Itaconic acid and derivatives such as DMI are interesting monomers because of their multiple functionalities and previous work has shown great potential. However, the multiple functionalities also pose challenges to avoid side reactions such as thermally initiated, premature, radical crosslinking and/or isomerization of the 1,1-disubstituted unsaturation. Additionally, the two carboxylic acids have inherently different reactivity. One key factor to control reactions with IA is to understand the performance of different catalysts. In this study, six esterification catalysts were investigated; immobilized Candida antarctica lipase B (CalB), titanium(IV)butoxide (Ti(OBu)4), p-toluenesulfonic acid (pTSA), sulfuric acid (H2SO4), 1,8-diazabicycloundec-7-ene (DBU), and 1,5,7-triazabicyclodec-5-ene (TBD). CalB and Ti(OBu)4 were selected for further characterization with appreciable differences in catalytic activity and selectivity towards DMI. CalB was the most effective catalysts and was applied at 60 °C while Ti(OBu)4 required 160 °C for a reasonable reaction rate. CalB was selective towards DMS and the non-conjugated side of DMI, resulting in polyesters with itaconate-residues mainly located at the chain ends, while Ti(OBu)4 showed low selectivity, resulting in polyesters with more randomly incorporated itaconate units. Thermal analysis of the polyesters showed that the CalB-catalyzed polyesters were semi-crystalline, whereas the Ti(OBu)4-catalyzed polyesters were amorphous, affirming the difference in monomer sequence. The polyester resins were crosslinked by UV-initiated free radical polymerization and the material properties were evaluated and showed that the crosslinked materials had similar material properties. The films from the polyester resins catalyzed by CalB were furthermore completely free from discoloration whereas the film made from the polyester resins catalyzed with Ti(OBu)4 had a yellow color, caused by the catalyst. Thus, it has been shown that CalB can be used to attain sustainable unsaturated polyesters resins for coating applications, exhibiting equally good properties as resins obtained from traditional metal-catalysis.

  • 14.
    Carlborg, Carl Fredrik
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Vastesson, Alexander
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Liu, Yitong
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Functional Off-Stoichiometry Thiol-ene-epoxy Thermosets Featuring Temporally Controlled Curing Stages via an UV/UV Dual Cure Process2014In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 52, no 18, p. 2604-2615Article in journal (Refereed)
    Abstract [en]

    We present a facile two-stage UV/UV activation method for the polymerization of off-stoichiometry thiol-ene-epoxy, OSTE+, networks. We show that the handling and processing of these epoxy-based resins is made easier by introducing a material with a controlled curing technique based on two steps, where the first step offers excellent processing capabilities, and the second step yields a polymer with suitable end-properties. We investigate the sequential thiol-ene and thiol-epoxy reactions during these steps by studying the mechanical properties, functional group conversion, water absorption, hydrolytic stability, and thermal stability in several different thiol-ene-epoxy formulations. Finally, we conclude that the curing stages can be separated for up to 24 h, which is promising for the usefulness of this technique in industrial applications.

  • 15.
    Claesson, Hans
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Synthesis and characterisation of star branched polyesters with dendritic cores and the effect of structural variations on zero shear rate viscosity2002In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 43, no 12, p. 3511-3518Article in journal (Refereed)
    Abstract [en]

    A series of branched polyesters consisting of poly(epsilon-caprolactone) (PCL) (degree of polymerisation: 5-200) initiated from hydroxy-functional cores and end-capped with methylmethacrylate have been prepared. The cores were third-generation hyperbranched polyester, Boltorn, with approximately 32 hydroxyl groups, a third-generation dendrimer with 24 hydroxyl groups and a third-generation dendron with eight hydroxyl groups. Finally, a linear PCL was synthesised as a reference material. All initiators were based on 2,2-bis(methylol) propionic acid (bis-MPA). C-13 NMR spectra of the polymers showed that those with shorter arms contained unreacted hydroxyl groups on the core. Rheological measurements of zero shear rate viscosity, eta(0), showed that the branched polyesters had a considerably lower eta(0) than linear polyester with similar molecular weight. The low melt viscosity and the crystallity produced a theological behaviour suitable for the film formation process for powder coatings. Measurements of mechanical properties of cured films showed that those with low arm molecular weight, M-a, were amorphous while those of high M-a were crystalline.

  • 16.
    Claesson, Hans
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Doyle, M.
    Manson, J. A. E.
    Rheological behaviour during UV-curing of a star-branched polyester2002In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 44, no 1, p. 63-67Article in journal (Refereed)
    Abstract [en]

    Using a rheometer coupled with an UV-light generator, the viscoelastic behaviour during the fast cure of star-branched polyester is investigated. The 32 arm star polymers consist of a hyperbranched polyester core, Boltorn(TM) and linear grafts of poly(E-caprolactone) (degree of polymerisation: 20-52) with methacrylate end groups. The resins are crystalline and the melting points range from 34 to 50degreesC; films can be formed and cured below 80degreesC. The crossover of G' and G was used as the gel point. The time to reach the gel point, a few seconds, increases linearly with molecular weight.

  • 17.
    Claesson, Hans
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Scheurer, Curzio
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Paulus, W.
    Schwalm, R.
    Semi-crystalline thermoset resins: tailoring rheological properties in melt using comb structures with crystalline grafts2004In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 49, no 1, p. 13-22Article in journal (Refereed)
    Abstract [en]

    Thermosetting resins with semi-crystalline grafts have been synthesized. An amorphous resin with epoxide groups was first functionalized with hydroxyl groups using 2,2-bis(methylol) propionic acid, bis-MPA in bulk at 155 degreesC. Functionalization with bis-MPA was monitored using FT-IR, FT-Raman and SEC. The reaction was complete in 30 min. Grafts of poly(epsilon-caprolactone) were then grown from the hydroxyl functional resin and end capped with methacrylate groups. The polymerization Of epsilon-caprolactone, performed in bulk at 110 degreesC using Sn(Oct)(2), was characterized using H-1 NMR and SEC. The obtained molecular weights agreed well with theoretical values. The final end capping was performed using methacrylic anhydride, and monitored with SEC and H-1 NMR, which indicated full substitution. Two combs were synthesized with different arm lengths, DP 10 and 20, and the obtained M-W were close to calculated values. The complex viscosity was measured from low to high temperature for the crystalline resins, the amorphous resin and blends thereof. Rheological data show a rapid decrease in viscosity within a temperature change of 10-15 degreesC for the crystalline resins while the amorphous resin exhibited a slow softening. The blends exhibited a behavior in-between that of the crystalline and the amorphous resin. Films were prepared from the pure resins and the blends. The films were cured using UV irradiation. The comb architecture of these resins has advantages such as crystallinity, high molecular weight and low viscosity, facilitating leveling and resulting in smooth films. The final film properties varied with the ratio of crystalline to amorphous resin, where increase in the amount of crystalline resin correlated with increased the flexibility.

  • 18.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Thiol-ene coupling of 1,2-disubstituted alkene monomers: The kinetic effect of cis/trans-isomer structures2010In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 46, no 12, p. 2321-2332Article in journal (Refereed)
    Abstract [en]

    The free-radical induced reaction between a tri-functional thiol (2-ethyl-(hydroxymethyl)-1,3-propanediol trimercapto propionate) and two 1,2-disubstituted alkenes (methyl oleate and methyl elaidate) has been investigated under photochemical conditions. The photoreaction was monitored via time-resolved FUR, Raman and NMR spectroscopy to provide insights about the kinetics and efficiency in end-product formation. The information collected was subjected to numerical modelling using the GEPASI software using pre-established literature values for the rate coefficients in order to verify the proposed reaction scheme. The results confirm the thiol-ene reaction mechanism showing a very fast cis/trans-isomerization (<1.0 min) when compared with the total disappearance of unsaturations, indicating that the rate-limiting step controlling the reaction is the hydrogen transfer from the thiol involved in the formation of product. High thiol-ene conversions can be obtained at reasonable rates without major influence of side-reactions when performed in bulk indicating that this reaction is suitable for network forming purposes with mono-unsaturated fatty acid methyl esters derivatives. The kinetic and mechanistic information collected provides a basis for the design of new thiol-ene systems aiming at material and coating applications.

  • 19.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Thiol-ene coupling kinetics of D-limonene: a versatile 'non-click' free-radical reaction involving a natural terpene2013In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, no 27, p. 11021-11034Article in journal (Refereed)
    Abstract [en]

    The free-radical photoinduced thiol-ene reaction between D-limonene, as renewable diolefinic substrate, and two mono-/tri-functional thiols (iso-tridecyl 3-mercaptopropionate and trimethylolpropane tris(3-mercaptopropionate)), has been investigated kinetically to define a relationship between alkene structure and reactivity. Separate thiol-ene solutions of the appropriate thiol in d-chloroform, supplemented with 1.0 wt% of DMPA (Irgacure 651), were subjected to polychromatic UV-irradiation and the chemical changes monitored discontinuously via H-1 NMR spectroscopy to quantify double bond conversion. The kinetic concentration profiles were modeled analytically and simulated in the application software COPASI for parameter estimation and to verify if the experimental data explained a suggested mechanistic scheme. Empirical results demonstrate that the external vinylidene bond of limonene reacts about 6.5 times faster with thiol than the internal trisubstituted 1-methyl-cyclohexene unsaturation. The selectivity observed for the two unsaturations was successfully explained by means of a simplified steady-state equation derived from the sequential reaction mechanism accounting for propagation and chain-transfer elementary steps with estimated rate coefficients. Kinetic modeling results attribute the difference in selectivity partially to steric impediments controlling thiyl-radical insertion onto the double bonds and predominantly to differences in relative energy between the two tertiary insertion carbon radical intermediates. The rate-limiting step was identified as the third chain-transfer hydrogen-abstraction reaction promoted by the second insertion carbon radical intermediate. High thiol-ene conversions were obtained in a timely fashion without major influence of secondary reactions demonstrating the suitability of this reaction for network forming purposes. The mechanistic and kinetic information collected can be used as a quantitative predictive tool to assess the potential use of D-limonene in thiol-ene network forming systems involving multifunctional alkyl ester 3-mercaptopropionates.

  • 20.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Utilizing Thiol-Ene Coupling Kinetics in the Design of Renewable Thermosed Resins based on D-Limonene and Polyfunctional ThiolsManuscript (preprint) (Other academic)
  • 21.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Utilizing thiol-ene coupling kinetics in the design of renewable thermoset resins based on D-limonene and polyfunctional thiols2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 20, p. 10317-10329Article in journal (Refereed)
    Abstract [en]

    An extended model is developed to predict the free-radical thiol-ene reaction dynamics between D-limonene, as a renewable diolefin, and a monothiol compound (iso-tridecyl 3-mercaptopropionate) in bulk liquid conditions. Thermally and photo-initiated reactions of the two monomers showed favored thiol-ene coupling at the exo-isopropenyl alkene structure when reacted at 1 : 1 and 1 : 0.5 mole ratios. Experimental kinetic data obtained from the two stoichiometries were well reproduced numerically via the simulation software COPASI by introducing a multi-route mechanistic scheme with propagation-chain-transfer steps accounting for primary (mono-additions) and secondary (di-addition) modes of coupling. The differences in intrinsic double-bond reactivity enable synthesis of limonene-terminated resins (mono-versus poly-disperse) as multifunctional network precursors. Off-stoichiometry manipulations in the initial mole ratio, assisted by numerical simulations, offer a convenient approach to visualize the overall reaction system kinetics irrespective of temporal effects, thus being regarded as an important guiding tool for chemists aiming at designing thiol-ene systems based on limonene.

  • 22.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Mathevet, Jeanne-Marie
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Bringing D-limonene to the scene of bio-based thermoset coatings via free-radical thiol-ene chemistry: macromonomer synthesis, UV-curing and thermo-mechanical characterization2014In: Polymer Chemistry, ISSN 1759-9954, Vol. 5, no 9, p. 3245-3260Article in journal (Refereed)
    Abstract [en]

    The increasing pursuit for bio-based plastic materials led us to investigate the potential use of the monoterpene limonene in thermoset synthesis using the free-radical mediated thiol-ene reaction. The high efficiency of this reaction to prepare multifunctional ene-terminated resins, as intermediary macromolecular precursors, for thermosets synthesis was demonstrated under thermal and photoinitiated conditions. Although an excess of terpene favors formation of well-defined macromonomers in organic solution, the characteristic low-vapor pressure of limonene hinders its simple removal (or recycling) via evaporation after synthesis. Alteration to an initial thiol-ene stoichiometry of 1 : 0.5 enables production of high molecular weight resins in the form of 'hyperbranched oligomeric-like' structures having moderate polydispersity. UV-curing of these polyfunctional resins combined with equal mole compositions of multifunctional alkyl ester 3-mercapto propionates yields highly sticky, amorphous and flexible elastomers with different thermo-mechanical properties. These can be further modulated by varying the amount of unreacted thiol occluded within the networks working as a plasticizer. Introduction of a renewable cycloaliphatic structure into the materials offers a convenient way to enhance the glass-transition temperature and stiffness of traditional thiol-ene networks. The materials synthesized may be considered potentially useful as sealants and adhesives in a wide variety of applications including organic coatings. The versatility of UV-irradiation over thermal initiation makes this method particularly suitable for green industrial synthesis processes via thiol-ene chemistry using limonene and multifunctional thiols. The thiol-ene system evaluated herein serves as a model example for the sustainable incorporation of natural diolefinic monomers into semisynthetic thiol-ene networks exhibiting a range of thermo-mechanical properties.

  • 23.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    van der Meulen, Inge
    Eindhoven University of Technology, Laboratory of Polymer Chemistry, Eindhoven, The Netherlands.
    Trey, Stacy
    SP Trätek, SP Technical Research Institute of Sweden, Stockholm.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Heise, Andreas
    Eindhoven University of Technology, Laboratory of Polymer Chemistry, Eindhoven, The Netherlands.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Photoinduced thiol-ene cross-linking of globalide/ε-caprolactone copolymers: curing performance and resulting thermoset properties2012In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 50, no 1, p. 16-24Article in journal (Refereed)
    Abstract [en]

    The increasing demand for bioderived polymers led us to investigate the potential use of the macrolactone globalide in thermoset synthesis via the photoinduced thiolene reaction. A series of six lipase-catalyzed poly(globalide-caprolactone) copolyesters bearing internal main-chain unsaturations ranging from 10 to 50 and 100 mol % were successfully crosslinked in the melt with equal amounts of thiol groups from trimethylolpropane-trimercapto propionate affording fully transparent amorphous elastomeric materials with different thermal and viscoelastic properties. Three major conclusions can be drawn from this study: (i) high thiol-ene conversions (> 80%) were easily attained for all cases, while maintaining the cure behavior, and irrespective of functionality at reasonable reaction rates; (ii) parallel chain-growth homopropagation of the ene monomer is insignificant when compared with the main thiolene coupling route; and (iii) high ene-density copolymers result in much lower extracted sol fractions and high T(g) values as a result of a more dense and homogeneous crosslinked network. The thiol-ene system evaluated in this contribution serve as model example for the sustainable use of naturally occurring 1,2-disubstituted alkenes in making semisynthetic polymeric materials in high conversions with a range of properties.

  • 24. Curia, S.
    et al.
    Barclay, A. F.
    Torron, Susana
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Howdle, S. M.
    Green process for green materials: viable low-temperature lipase-catalysed synthesis of renewable telechelics in supercritical CO22015In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 373, no 2057, article id 20150073Article in journal (Refereed)
    Abstract [en]

    We present a novel near-ambient-temperature approach to telechelic renewable polyesters by exploiting the unique properties of supercritical CO2 (scCO(2)). Bio-based commercially available monomers have been polymerized and functional telechelic materials with targeted molecular weight prepared by end-capping the chains with molecules containing reactive moieties in a one-pot reaction. The use of scCO(2) as a reaction medium facilitates the effective use of Candida antarctica Lipase B (CaLB) as a catalyst at a temperature as low as 35 degrees C, hence avoiding side reactions, maintaining the end-capper functionality and preserving the enzyme activity. The functionalized polymer products have been characterized by H-1 nuclear magnetic resonance spectroscopy, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, gel permeation chromatography and differential scanning calorimetry in order to carefully assess their structural and thermal properties. We demonstrate that telechelic materials can be produced enzymatically at mild temperatures, in a solvent-free system and using renewably sourced monomers without pre-modification, by exploiting the unique properties of scCO(2). The macromolecules we prepare are ideal green precursors that can be further reacted to prepare useful bio-derived films and coatings.

  • 25.
    Eriksson, Magnus
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Boyer, Antoine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Sinigoi, Loris
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    One-Pot Enzymatic Route to Tetraallyl Ether Functional Oligoesters: Synthesis, UV Curing, and Characterization2010In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 48, no 23, p. 5289-5297Article in journal (Refereed)
    Abstract [en]

    An enzymatic one-pot route in bulk was used to synthesize tetraallyl ether (tAE) functional oligomers based on divinyl adipate, 1,4-butanediol and trimethylolpropane diallyl ether. By using lipase B from Candida antarctica as catalyst and varying the stoichiometric ratio of monomers, it was possible to reach targeted molecular weights (from 1300 to 3300 g mol(-1)) of allyl-ether functional polyesters. The enzyme catalyzed reaction reached completion (>98% conversion based on all monomers) within 24 h at 60 degrees C, under reduced pressure (72 mbar) resulting in similar to 90% yield after filtration. The tAE-functional oligoesters were photopolymerized, without any purification other than removal of the enzyme by filtration, with thiol functional monomers (dithiol, tetrathiol) in a 1: 1 ratio thiol-ene reaction. The photo-initiator, 2,2-dimethoxy-2-phenylacetophenone, was used to improve the rate of reaction under UV light. High conversions (96-99% within detection limits) were found for all thiol-ene films as determined by FT-Raman spectroscopy. The tAE-functional oligoesters were characterized by NMR, MALDI, and SEC. The UV-cured homopolymerized films and the thiol-ene films properties were characterized utilizing DSC and DMTA.

  • 26.
    Eriksson, Magnus
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Enzymatic One-Pot Route to Telechelic Polypentadecalactone Epoxide: Synthesis, UV Curing, and Characterization2009In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, no 11, p. 3108-3113Article in journal (Refereed)
    Abstract [en]

    In an enzymatic one-pot procedure immobilized lipase B from Candida antarctica was used to synthesize semicrystalline diepoxy functional macromonomers based on glycidol, pentadecalactone, and adipic acid. By changing the stoichiometry of the building blocks. macromonomers of controlled molecular weight front 1400 to 2700 g mol(-1) could be afforded. The enzyme-catalyzed reaction went to completion (conversion >= 95%) within 24 h at 60 degrees C. After removal of the enzyme, the produced macromonomers were used for photopolymerization without any purification. The macromonomers readily copolymerized cationically with a cycloaliphatic diepoxide (Cyracure UVR-6110; CA-dE) to high conversion. The cross-linked copolymers formed a durable film with a degree of crystallinity depending on the macromonomer size and amount of CA-dE used, without CA-dE the macromonomers homopolymerized only to a low degree. Combined with CA-dE conversions of 85-90% were determined by FT-Raman spectroscopy. The films became more durable once reinforced with CA-dE, increasing the cross-link density and reducing the crystallinity of the PDL segments in the films.

  • 27.
    Eriksson, Magnus G.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Trey, Stacy M.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    One-pot enzymatic polycondensation to telechelic methacrylate-functional oligoesters used for film formation2011In: POLYM CHEM, ISSN 1759-9954, Vol. 2, no 3, p. 714-719Article in journal (Refereed)
    Abstract [en]

    Based on largely renewable monomers, an enzymatic one-pot polycondensation route towards functional oligomers with targeted molecular weights and end-groups was developed. This one-pot synthesis was performed by combining Candida antarctica lipase B (CALB), 2-hydroxyethyl methacrylate (HEMA), ethylene glycol, and divinyl adipate under reduced pressure (72 mbar) at 60 degrees C. The polymerization went to completion (>95% conversion for all monomers) within 24 h and the fraction of methacrylate end-groups was >90%. Three targeted dimethacrylate functional oligomers with molecular weights of 920, 1700 and 2500 g mol(-1) (degrees of polymerization 4, 8, and 13 respectively) were synthesized. The oligomer products were characterized by NMR, MALDI-TOF MS and SEC. The dimethacrylate functional oligomers were further UV homopolymerized or combined with a tetrathiol crosslinker to demonstrate the potential to produce novel networks with tunable thermal properties dependent on chain length of the telechelic building blocks. This research is the first to demonstrate methacrylate functionalization and condensation polymerization in a one step process, which expands the growing toolbox for polymer/material chemists towards an increased throughput in available macromonomers used in material design.

  • 28.
    Eriksson, Magnus
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Nilsson, Camilla
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    One-pot synthesis to functional free-standing polymer film for sensor applicationsManuscript (preprint) (Other academic)
  • 29.
    Finnveden, Maja
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Nameer, Samer
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats K G
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    One-Component Thiol-Alkene Functional Oligoester Resins Utilizing Lipase Catalysis2016In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935Article in journal (Refereed)
    Abstract [en]

    Chemo-enzymatic methods are powerful tools for the synthesis of novel materials. By combining the flexibility of chemical synthesis and the high selectivity of enzymes, a variety of functional materials can be achieved. In the present study, a series of α,ω-thiol telechelic oligoesters with varying amount of internal alkenes are prepared using selective lipase catalysis and are subsequently cross-linked by thiol-ene chemistry yielding alkene functional networks. Due to the reactivity of thiols and alkenes almost all present thiol-ene systems consist of two components. This work demonstrates that selective lipase catalysis in combination with renewable monomers with internal alkenes is a promising system for achieving one-component thiol-alkene functional resins with good storage stability and a high degree of thiol end-groups. The developed chemo-enzymatic route yields polymer networks with tailored amount of alkene functionalities in the final thermoset, which facilitate further postmodification.

  • 30.
    Fogelström, Linda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hard and flexible Coatings based on Nanoparticle-filled hyperbranched Polymers2007In: Polymer Preprints, ISSN 0032-3934, Vol. 48, no 2, p. 436-437Article in journal (Refereed)
  • 31.
    Fogelström, Linda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hard and Flexible Nanocomposite Coatings using Nanoclay‐filled Hyperbranched Polymers2010In: ACS Applied Materials and Interfaces, ISSN 1944-8244, Vol. 2, no 6, p. 1679-1684Article in journal (Refereed)
    Abstract [en]

    The combination of hardness, scratch resistance, and flexibility is a highly desired feature in many coating applications. The aim of this study is to achieve this through the introduction of an unmodified nanoclay, montmorillonite (Na+MMT), in a polymer resin based on the hyperbranched polyester Bottom H30. Smooth and transparent films were prepared from both the neat and the nanoparticle-filled hyperbranched resins. X-ray diffraction (XRD) and transmission electron microscopy (TEM) corroborated a mainly exfoliated structure in the nanocomposite films, which was also supported by results from dynamic mechanical analysis (DMA). Furthermore, DMA measurements showed a 9-16 degrees C increase in Tg and a higher storage modulus above and below the T-g-both indications of a more cross-linked network, for the clay-containing film. Thermogravimetric analysis (TGA) demonstrated the influence of the nanofiller on the thermal properties of the nanocomposites, where a shift upward of the decomposition temperature in oxygen atmosphere is attributed to the improved barrier properties of the nanoparticle-filled materials. Conventional coating characterization methods demonstrated an increase in the surface hardness, scratch resistance and flexibility, with the introduction of clay, and all coatings exhibited excellent chemical resistance and adhesion.

  • 32. Glauser, T.
    et al.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Kornmann, X.
    Berglund, Lars A.
    Toughening of electron-beam cured acrylate resins2000In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 280, no 08-jul, p. 20-25Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to improve the toughness of EB-cured acrylate thermost resins by using hyperbranched aliphatic polyesters as additives to obtain a liquid-liquid phase-separated resin. The hyperbranched polyester can be considered as a hydroxyl functional scaffold, on which functional groups were reacted by control phase separation and crosslinking. Alkyl chains of different lengths attached to the scaffold controlled phase separation. The amount of crosslinking within the rubbery particle and between the particles and the matrix was set by the percentage of methacrylate groups. A good phase separation was obtained; therefore, T-g decreased only slightly compared to the pure acrylate. The K-IC value of the cured resins was increased by 30%. The phase-separated resins showed stability with time and no significant increase in particle size was noticed after 18 months.

  • 33. Glauser, T
    et al.
    Johansson, Mats
    Hult, Anders
    Electron-beam curing of thick thermoset composite matrices1999In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 40Article in journal (Refereed)
  • 34. Glauser, T.
    et al.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    A comparison of radiation and thermal curing of thick composites2000In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 274, no 1, p. 25-30Article in journal (Refereed)
    Abstract [en]

    This work aimed to compare three different techniques to cure thick composite matrices to see the effect of the process on the network and the thermomechanical properties of the polymer matrix. Two different thermoset resins. one acrylate and one methacrylate, have been free-radically cured with high-energy electron beam (EB), ultra-violet light (UV) ol heat (thermal). The differences in curing mechanisms as well as the thermomechanical properties of the cured resins have been investigated. For this type of resins, EB-cured samples showed the highest thermo-mechanical properties and the lowest residual unsaturation. Thermally cured resins showed similar properties, but with drawbacks such as long curing cycles and thermal degradation in the matrix. The cure did not proceed to the same extent in the UV-cured samples. But the simplicity of the curing equipment makes UV-curing an interesting complement to thermal or EB-curing.

  • 35. Glauser, T.
    et al.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Electron-beam curing of thick thermoset composites: Effect of temperature and fiber2000In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 274, no 1, p. 20-24Article in journal (Refereed)
    Abstract [en]

    Electron-beam curing of thermoset resins used in fiber-reinforced composites has been investigated. Two resins, a bisphenol-A acrylate and methacrylate, were used as model systems. The temperature was monitored during cure to know the thermal history of the composite during cure. The thermo-mechanical properties were measured on the cured samples. It could be seen that all these values were influenced by the nature (glass or carbon) and amount (0-50 wt.-%) of fiber. A linear correlation was found between the maximum temperature during cure and the glass transition temperature. It was shown that it is possible to compensate for alack of heat during dire in systems with too low exotherms. Some influence on the network homogeneity was also noticed when the thermal energy available during cure was too low.

  • 36.
    Haraldsson, Klas Tommy
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Bowman, Christopher N.
    Hult, Anders
    KTH, Superseded Departments, Fibre and Polymer Technology.
    The Effects of Hydrogen Abstraction on the Kinetics of Monofunctional Maleate/ Vinyl Ether Radical PhotopolymerizationsManuscript (Other academic)
  • 37.
    Haraldsson, Klas Tommy
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    The Effects of Abstractable Hydrogen in Radical Photopolymerization of Maleate/Vinyl Ether Monomers Studied with EPR and Photo-RTIR2010In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 48, no 13, p. 2810-2816Article in journal (Refereed)
    Abstract [en]

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

  • 38. Hassel, Beatriz I.
    et al.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. SP Tech Res Inst Sweden, Sweden.
    Leijonmarck, Simon
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    A Study on the Morphology, Mechanical, and Electrical Performance of Polyaniline-modified Wood - A Semiconducting Composite Material2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 3, p. 5007-5023Article in journal (Refereed)
    Abstract [en]

    This study investigated the morphology, electrochemical modification with respect to the wood fiber direction, and mechanical properties of wood modified by in situ polymerization with polyaniline (PANI). This polymerization formed a composite material with applications as an antistatic, electromagnetic, anti-corrosion, and heavy metal purifying materials. The polymer was found throughout the entire structure of the wood and was quantified within the wood cell wall and middle lamella by SEM-EDX. The presence of PANI affected the conductivity of the composite specimens, which was found to be higher in the fiber direction, indicating a more intact percolation pathway of connected PANI particles in this direction. The PANI modification resulted in a small reduction of the storage modulus, the maximum strength, and the ductility of the wood, with decreases in the properties of specimens conditioned in an environment above 66% relative humidity. The in situ-polymerized PANI strongly interacted with the lignin component of the veneers, according to the decrease in the lignin glass transition temperature (T-g) noted in DMA studies.

  • 39.
    Hedenqvist, Mikael S.
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Yousefi, Hamid Reza
    KTH, Superseded Departments, Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Gedde, Ulf W.
    KTH, Superseded Departments, Polymer Technology.
    Trollsas, M.
    Hedrick, J. L.
    Transport properties of hyperbranched and dendrimer-like star polymers2000In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 41, no 5, p. 1827-1840Article in journal (Refereed)
    Abstract [en]

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

  • 40. Hellberg, J
    et al.
    Remonen, T
    Johansson, Mats
    Inganas, O
    Theander, M
    Engman, L
    Eriksson, P
    New monomers for polythiophenes1997In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 84Article in journal (Refereed)
  • 41.
    Henriksson, Marielle
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    New nanocomposite concept based on crosslinking of hyperbranched polymers in cellulose nanopaper templates2010In: International Conference on Nanotechnology for the Forest Products Industry 2010, 2010, p. 880-897Conference paper (Refereed)
  • 42.
    Henriksson, Marielle
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Novel nanocomposite concept based on cross-linking of hyperbranched polymers in reactive cellulose nanopaper templates2011In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 71, no 1, p. 13-17Article in journal (Refereed)
    Abstract [en]

    Cellulosic fibers offer interesting possibilities for good interfacial adhesion due to the high density of hydroxyl groups at the surface. in the present study, the potential of a new nanocomposite concept is investigated, where a porous cellulose nanofiber network is impregnated with a solution of reactive hyperbranched polyester. The polymer is chemically cross-linked to form a solid matrix. The resulting nanocomposite structure is unique. The matrix surrounds a tough nanopaper structure consisting of approximately 20 nm diameter nanofibers with an average interfiber distance of only about 6 nm. The cross-linked polymer matrix shows strongly altered characteristics when it is cross-linked in the confined space within the nanofiber network, including dramatically increased T-g, and this must be due to covalent matrix-nanofiber linkages.

  • 43.
    Henriksson, Marielle
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Berglund, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    A new nanocomposites approach for strong attachment of polymer matrices to cellulose nanofibril networksManuscript (Other academic)
  • 44.
    Huang, Hui
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Shandong University, China.
    Dobryden, Illia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Ihrner, Niklas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Ma, Houyi
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Technical Research Institute of Sweden, Sweden.
    Temperature-dependent surface nanomechanical properties of a thermoplastic nanocomposite2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 494, p. 204-214Article in journal (Refereed)
    Abstract [en]

    In polymer nanocomposites, particle-polymer interactions influence the properties of the matrix polymer next to the particle surface, providing different physicochemical properties than in the bulk matrix. This region is often referred to as the interphase, but detailed characterization of its properties remains a challenge. Here we employ two atomic force microscopy (AFM) force methods, differing by a factor of about 15 in probing rate, to directly measure the surface nanomechanical properties of the transition region between filler particle and matrix over a controlled temperature range. The nanocomposite consists of poly(ethyl methacrylate) (PEMA) and poly(isobutyl methacrylate) (PiBMA) with a high concentration of hydrophobized silica nanoparticles. Both AFM methods demonstrate that the interphase region around a 40-nm-sized particle located on the surface of the nanocomposite could extend to 55–70 nm, and the interphase exhibits a gradient distribution in surface nanomechanical properties. However, the slower probing rate provides somewhat lower numerical values for the surface stiffness. The analysis of the local glass transition temperature (Tg) of the interphase and the polymer matrix provides evidence for reduced stiffness of the polymer matrix at high particle concentration, a feature that we attribute to selective adsorption. These findings provide new insight into understanding the microstructure and mechanical properties of nanocomposites, which is of importance for designing nanomaterials.

  • 45. Hult, Anders
    et al.
    Johansson, Mats
    Malmström, Eva
    DENDRITIC RESINS FOR COATING APPLICATIONS1995In: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 98Article in journal (Refereed)
  • 46. Hult, Anders
    et al.
    Johansson, Mats
    Malmström, Eva
    Hyperbranched polymers1999In: Branched Polymers II, Springer-Verlag New York, 1999, Vol. 143, p. 1-34Chapter in book (Other academic)
  • 47. Hult, Anders
    et al.
    Malmström, Eva
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Johansson, Mats
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Sörensen, Kent
    Dendritic macromolecule, process for preparation thereof and use thereof1992Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The invention relates to a dendritic macromolecule of the polyester type comprising a central initiator molecule or initiator polymer having one or more reactive hydroxyl groups (A). The groups (A) are under formation of an initial tree structure bonded to reactive carboxyl groups (B) of a monomeric chain extender having the two reactive groups (A) and (B). The tree structure is optionally extended and further branched from the initiator molecule or initiator polymer by addition of further molecules of a monomeric chain extender by means of bonding between the reactive groups (A) and (B) thereof and is thereafter optionally further extended by reaction with a chain stopper. The invention also comprises a process for preparation of the dendritic macromolecule.

  • 48.
    Ihrner, Niklas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Johannisson, Wilhelm
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Sieland, Fabian
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Structural lithium ion battery electrolytes via reaction induced phase-separation2017In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 48, p. 25652-25659Article in journal (Refereed)
    Abstract [en]

    For the realization of structural batteries, electrolytes where both higher ionic conductivity and stiffness are combined need to be developed. The present study describes the formation of a structural battery electrolyte (SBE) as a two phase system using reaction induced phase separation. A liquid electrolyte phase is combined with a stiff vinyl ester based thermoset matrix to form a SBE. The effect of monomer structure variations on the formed morphology and electrochemical and mechanical performance has been investigated. An ionic conductivity of 1.5 x 10(-4) S cm(-1), with a corresponding storage modulus (E') of 750 MPa, has been obtained under ambient conditions. The SBEs have been combined with carbon fibers to form a composite lamina and evaluated as a battery half-cell. Studies on the lamina revealed that both mechanical load transfer and ion transport are allowed between the carbon fibers and the electrolyte. These results pave the way for the preparation of structural batteries using carbon fibers as electrodes.

  • 49.
    Ihrner, Niklas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Improved performance of solid polymer electrolytes for structural batteries utilizing plasticizing co-solvents2017In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 134, no 23, article id 44917Article in journal (Refereed)
    Abstract [en]

    This study describes the formulation, curing, and characterization of solid polymer electrolytes (SPE) based on plasticized poly(ethylene glycol)-methacrylate, intended for use in structural batteries that utilizes carbon fibers as electrodes. The effect of crosslink density, salt concentration, and amount of plasticizer has been investigated. Adding a plasticizing solvent increases the overall performance of the SPE. Increased ionic conductivity and mechanical performance can be attained compared to similar systems without plasticizer. At ambient temperature, ionic conductivity (sigma) of 3.3 x 10(-5) Scm(-1), with a corresponding storage modulus (E) of 20 MPa are reached.

  • 50.
    Jafarzadeh, Shadi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Sundell, P. -E
    Claudino, Mauro
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    UV-curable acrylate-based nanocomposites: Effect of polyaniline additives on the curing performance2013In: Polymers for Advanced Technologies, ISSN 1042-7147, E-ISSN 1099-1581, Vol. 24, no 7, p. 668-678Article in journal (Refereed)
    Abstract [en]

    Composites of nanostructured polyaniline (PANI) conducting polymer in a polyester acrylate (PEA) formulation were made to provide conductive organic coatings. The effect of the presence and amount of PANI on the photocuring performance of the ultraviolet (UV)-curable acrylate system has been investigated employing real-time Fourier transform infrared spectroscopy as the main technique. Longer initial retardation of the radical polymerization and lower rates of cross-linking reactions were observed for dispersions containing PANI of higher than 3wt.%. The PEA/PANI samples were more affected than the neat PEA resin by the changes in UV light intensity and oxygen accessibility during UV curing. Samples with higher PANI content, of up to 10wt.%, were tested and could be partially cured even at UV light intensities as low as 2mW cm-2 when the oxygen replenishment into the system was inhibited. Thermal analysis revealed that the presence of PANI did not induce any significant change in Tg of the cured system, meaning that early decrease in mobility and vitrification is not the reason for lower ultimate conversion of the dispersions with higher PANI content compared with the neat PEA resin. Curing under strong UV lamps, of 1.5W cm-2 intensity, made it possible to reach high degrees of conversion on films with similar mechanical properties independent of the PANI content.

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