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  • 1.
    Albertsson, Ann-Christine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    David, G.
    Strandberg, C.
    Bilba, D.
    Paduraru, C.
    Synthesis of core-shell structured carboxylated microparticles with a straightforward procedure and their evaluation as a polymer support2005In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 43, no 23, p. 5889-5898Article in journal (Refereed)
    Abstract [en]

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

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    KTH, Superseded Departments, Fibre and Polymer Technology.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    KTH, Superseded Departments, Fibre and Polymer Technology.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    KTH, Superseded Departments, Fibre and Polymer Technology.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

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

  • 3. Atlas, Salima
    et al.
    Raihane, Mustapha
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Lahcini, Mohammed
    Ameduri, Bruno
    Radical copolymerization of acrylonitrile with 2,2,2-trifluoroethyl acrylate for dielectric materials: Structure and characterization2013In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 51, no 18, p. 3856-3866Article, review/survey (Refereed)
    Abstract [en]

    Radical copolymerization based on acrylonitrile (AN) and 2,2,2-Trifluoroethyl acrylate (ATRIF) initited by AIBN was investigated in acetonitrile solution. The resulting poly(AN-co-ATRIF) copolymers were characterized by 1 H, 13 C, and 19 F NMR and IR spectroscopy, and size exclusion chromatography (SEC). Their compositions were assessed by 1 H NMR. The kinetics of radical copolymerization of AN with ATRIF was investigated from sereval experiments achieved at 70 degrees C from initial [AN](0)/[ATRIF](0) molar ratios ranging between 20/80 and 80/20 and was enabled to determine the reactivity ratios of both comonomers. From the monomer-polymer copolymerization curve, the Fineman-Ross and Kelen-Tudos laws enabled to assess the reactivity ratios (r(AN) = r(1) = 1.25 +/- 0.04 and r(ATRIF) = r(2) = 0.93 +/- 0.05 at 70 degrees C) while the revised patterns scheme led to r(12) = r(AN) = 1.03, and r(21) = r(ATRIF) = 0.78 at 70 degrees C. In all cases, rAN x rATRIF product was close to unity, which indicates that poly(AN-co-ATRIF) copolymers exhibit a random structure. This was also confirmed by the Igarashi's and Pyun's laws which revealed the presence of AN-ATRIF, AN-AN, and ATRIF-ATRIF dyads. The Q and e values for ATRIF were also assessed (Q(2) = 0.62 and e(2) = 0.93). The glass transition temperature values, Tg, of these copolymers increased from 17 to 61 degrees C as the molar percentage of ATRIF decreased from 77 to 16% in the copolymer. Thermogravimetry analysis of poly(AN-co-ATRIF) copolymers showed a good thermal stability compared to that of poly(ATRIF) homopolymer due to incorporation of AN comonomer.

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

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

  • 5.
    Burman, Lina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Evaluation of Long-Term Performance of Antioxidants Using Prooxidants instead of Thermal Acceleration2005In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 43, no 19, p. 4537-4546Article in journal (Refereed)
    Abstract [en]

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

  • 6.
    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.

  • 7.
    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.

  • 8. Dax, Daniel
    et al.
    Xu, Chunlin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Langvik, Otto
    Hemming, Jarl
    Backman, Peter
    Willför, Stefan
    Synthesis of SET-LRP-Induced Galactoglucomannan-Diblock Copolymers2013In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 51, no 23, p. 5100-5110Article in journal (Refereed)
    Abstract [en]

    Polysaccharides are biorenewable and biodegradable starting materials for the development of functional materials. The synthesis of a monofunctional macroinitiator for single electron transfer-living radical polymerization was successfully developed from a wood polysaccharide-O-acetyl galactoglucomannan (GGM) using a beforehand synthesized amino-functional -bromoisobutyryl derivative applying reductive amination. The GGM macroinitiator was employed to initiate a controlled radical polymerization of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA), methyl methacrylate (MMA), and N-isopropylacrylamide (NIPAM) using Cu-0/Me-6-Tren as a catalyst. The either charged or amphiphilic GGM-b-copolymers with different chain lengths of the synthetic block were successfully synthesized without prior hydrophobization of the GGM chain and dimethyl sulfoxide (DMSO) or DMSO/water mixtures were used as solvents. This novel synthetic approach may find untapped potentials particularly for the development of polysaccharide-based amphiphilic additives for cosmetics or paints and for the design of novel temperature or pH responsive polymers with such potential applications as in drug delivery systems or in biocomposites.

  • 9.
    Edlund, Ulrica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Macroinitiator Halide Effects in Galactoglucomannan-Mediated Single Electron Transfer-Living Radical Polymerization2011In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 49, no 19, p. 4139-4145Article in journal (Refereed)
    Abstract [en]

    Chloro (Cl)- and bromo (Br)-functionalized macroinitiators were successfully prepared from the softwood hemicellulose O-acetylated galactoglucomannan (AcGGM) and then explored and evaluated with respect to their ability and efficiency of initiating single electron transfer-living radical polymerization (SET-LRP). Both halogenated species effectively initiate SET-LRP of an acrylate and a methacrylate monomer, respectively, yielding brushlike AcGGM graft copolymers, where the molecular weights are accurately controlled via the monomer:macroinitiator ratio and polymerization time over a broad range: from oligomeric to ultrahigh. The nature of the halogen does not influence the kinetics of polymerization strongly, however, for acrylate graft polymerization, AcGGM-Cl gives a somewhat higher rate constant of propagation, while methacrylate grafting proceeds slightly faster when the initiating species is AcGGM-Br. For both monomers, the macroinitiator efficiency is superior in the case of AcGGM-Br.

  • 10.
    Edlund, Ulrica
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Morphology engineering of a novel poly(L-lactide)/poly(1,5-dioxepan-2-one) microsphere system for controlled drug delivery2000In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 38, no 5, p. 786-796Article in journal (Refereed)
    Abstract [en]

    Morphology is presented as a powerful tool to control the in vitro degradation and drug release characteristics of novel drug delivery microspheres prepared from homopolymer blends of 1,5-dioxepan-2-one, DXO, and L-lactide, L-LA. Their performance in this respect was compared to analogous P(L-LA-co-DXO) microspheres. Blends formed denser and less porous microspheres with a higher degree of matrix crystallinity than copolymers of corresponding L-LA:DXO composition. The morphology differences of blends and copolymers, further adjustable by means of component ratio, are shown to have a vital impact on the in vitro performance. Sustained drug delivery was obtained from both copolymers and blends. Molecular weight; loss was retarded and diffusion-mediated release was inhibited in the latter case, further delaying the release process. The effects of storage on the physicochemical properties of these systems were evaluated under desiccated and moist conditions for 5 months. Storage-induced physicochemical changes, such as matrix crystallization and molecular weight decrease, were accelerated at higher relative humidities. P(L-LA-co-DXO) demonstrated higher moisture sensitivity than a PLLA-PDXO blend of corresponding composition. The more crystalline and dense morphology of blend microspheres may thus be considered an improvement of the storage stability.

  • 11.
    Edlund, Ulrica
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Novel drug delivery microspheres from poly(1,5-dioxepan-2-one-co-L-lactide)1999In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 37, no 12, p. 1877-1884Article in journal (Refereed)
    Abstract [en]

    Novel microspheres from copolymers of 1,5-dioxepan-2-one (DXO) and L-lactide (L-LA) were prepared by oil-in-water solvent evaporation and oil-in-oil solvent removal. The two preparation techniques were evaluated for sphere formulation and incorporation of two different drugs. Sustained release of these therapeutic substances was obtained. The consequences of altering the DXO : LA ratio, preparation method, and drug hydrophilicity were explored and identified as factors governing sphere quality, in vitro degradation, and drug release characteristics. We show that these relationships provide a powerful means of controlling the microsphere performance.

  • 12.
    Edlund, Ulrica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    SET-LRP Goes "Green": Various Hemicellulose Initiating Systems Under Non-Inert Conditions2012In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 50, no 13, p. 2650-2658Article in journal (Refereed)
    Abstract [en]

    Robust and versatile controlled radical polymerization, also in air, was achieved via single electron transfer living radical polymerization (SET-LRP) initiated by purposely designed hemicellulose-derived macroinitiators. The efficiency of the substitution reaction, converting the polysaccharides into bromo-multifunctionalized initiators, as well as the rate of subsequent induced polymerizations of methyl acrylate were controlled by the hemicellulose repeating unit structure, branching pattern, and molecular weight. Macroinitiators with mannan-based backbones induce SET-LRP with somewhat higher apparent rate constants than xylan-derived analogues, increasing by a factor two to three when raising the reaction temperature from 25 to 40 degrees C. The presence of lignin in a non-purified xylan fraction did not impair its viability as a macroinitiator. Hemicellulose-initiated SET-LRP was feasible in air, proceeding with comparable or somewhat higher apparent rate constants than when conducted under deoxygenated conditions.

  • 13.
    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.

  • 14.
    Finne, Anna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    New functionalized polyesters to achieve controlled architectures2004In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 42, no 3, p. 444-452Article in journal (Refereed)
    Abstract [en]

    Following our continued interest in the production of bioerodible and biodegradable functional polymers for biomedical applications, we synthesized and characterized new unsaturated polyesters. The presence of functional groups in the polymer backbone provided sites for chemical modification, and through a variation in the structure, the physical properties, such as the hydrophilicity and solubility, could be affected. With 1,1-di-n-butyl-stanna-2,7-dioxacyclo-4-heptene as the initiator in the ring-opening polymerization of polyesters, a new set of functionalized polyesters was created. The polymerization of epsilon-caprolactone resulted in poly(epsilon-caprolactone) with a double bond incorporated into the structure. The polymers were obtained in a controlled manner with low molecular dispersities. The double bond was previously incorporated into L-lactide polymers, and the two reactions were compared in this study. The conversion of E-caprolactone, with a degree of polymerization of 50, was completed within 140 min, whereas for L-lactide, only a 45% conversion took place in the same period of time. The dispersities were somewhat higher with E-caprolactone because of the higher reaction rate and, therefore, lower selectivity. The incorporated C-C double bond in the polyesters provided a variety of opportunities for further modifications. In this case, the double bond of the L-lactide macromonomers was oxidized into epoxides. Epoxidation was carried out with m-chloroperoxybenzoic acid as a chemical reagent. The conversion of the double bonds into epoxides was completed, and the obtained yields were good (>95%). As a result of the mild reaction conditions, the epoxidation of the double bond was carried out quantitatively without any side reactions.

  • 15.
    Finne, Anna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Polyester hydrogels with swelling properties controlled by the polymer architecture, molecular weight, and crosslinking agent2003In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, no 9, p. 1296-1305Article in journal (Refereed)
    Abstract [en]

    Hydrogels of poly(1,5-dioxepan-2-one) and hydrogels of block copolymers of poly(1,5-dioxepan-2-one) and poly(L-lactide) were synthesized. Both star-shaped polymers and linear polymers were polymerized with ring-opening polymerization and crosslinked in situ with a tetrafunctional acid chloride (1,2,3,4-cyclopentane tetracarboxylic acid chloride) or a difunctional acid chloride (succinyl chloride). Different network architectures were synthesized in this way. The initial monomer concentrations and the molecular weights of the macromonomers were also altered. The networks were characterized with H-1 NMR and differential scanning calorimetry, and the swelling abilities of the different hydrogels were investigated in water and dichloromethane. The ratio of the monomer to the crosslinking agent was assessed by the quantification of the signal intensities in the H-1 NMR spectra of the swelled network and agreed with the theoretical crosslinking density. Both the homopolymers of 1,5-dioxepan-2-one and the copolymers of 1,5-dioxepan-2-one and L-lactide swelled to a high degree in water. The swelling properties of the materials could be varied over a broad range by changes in the architecture, molecular weight, and content of the precursor in the network. Star-shaped poly(1,5-dioxepan-2-one) crosslinked with a difunctional acid chloride had the highest degree of swelling among the different homopolymer hydrogels. This network also had the lowest glass-transition temperature because of the flexible units in the structure. The same trends found for the homopolymer hydrogels were also seen in the hydrogels with block copolymers. The hydrogels swelled enormously in dichloromethane, and as in water, the star-shaped copolymer crosslinked with a difunctional acid chloride had the highest degree of swelling.

  • 16.
    Finne, Anna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Reema,
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Use of germanium initiators in ring-opening polymerization of L-lactide2003In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, no 19, p. 3074-3082Article in journal (Refereed)
    Abstract [en]

    Three different, new germanium initiators were used for ring-opening polymerization Of L-lactide. Chlorobenzene and 120 degreesC was a usable polymerization system for solution polymerization, and the results from the polymerizations depended on the initiator structure and bulkiness around the insertion site. The average molecular weights as measured by size exclusion chromatography increased linearly with the monomer conversion, and the molecular weight dispersity was around 1.2 for initiators 1 and 2, whereas it was around 1.4 for initiator 3. The average molecular weight of poly(L-lactide) could be controlled with all three initiators by adding different ratios of monomer and initiator. The reaction rate for the solution polymerization was, however, overall extremely slow. With an initial monomer concentration of 1 M and a monomer-to-initiator ratio of 50, the conversion was 93% after 161 h for the fastest initiator. In bulk polymerization, 160 degreesC, the conversion was 90% after 10 h.

  • 17. Ghirardello, Mattia
    et al.
    Öberg, Kim
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Staderini, Samuele
    Renaudet, Olivier
    Berthet, Nathalie
    Dumy, Pascal
    Hed, Yvonne
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Marra, Alberto
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Dondoni, Alessandro
    Thiol-Ene and Thiol-Yne-Based Synthesis of Glycodendrimers as Nanomolar Inhibitors of Wheat Germ Agglutinin2014In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 52, no 17, p. 2422-2433Article in journal (Refereed)
    Abstract [en]

    Alkene and alkyne functional polyester-based dendrimers of generation 1 to 4 have been prepared and reacted under free-radical conditions with 2-acetamido-2-deoxy-1-thio--D-glucose (GlcNAc-SH). As the alkene-dendrimers underwent the addition of one thiyl radical per ene group whereas each yne group of alkyne-dendrimers was saturated by two thiyl radicals, a collection of glycodendrimers with glycan density ranging from six to ninety-six GlcNAc per dendrimer was obtained. The recognition properties of the prepared glycodendrimers toward the wheat germ agglutinin (WGA) were evaluated by enzyme-linked lectin assay (ELLA). The eight glycodendrimers were excellent ligands showing IC50 values in the nanomolar range and relative potencies per sugar unit up to 2.27 e(6) when compared to monosaccharidic GlcNAc used as monovalent reference.

  • 18.
    Guo, Baolin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Versatile Functionalization of Polyester Hydrogels with Electroactive Aniline Oligomers2011In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 49, no 9, p. 2097-2105Article in journal (Refereed)
    Abstract [en]

    Functionalizing aliphatic polyester hydrogels with an aniline oligomer is a means of achieving electrically conductive and degradable hydrogels. To lower the aniline oligomer content while maintaining a high conductivity and to overcome the acidic degradation product from polylactide reported in our previous work, a series of electroactive and degradable hydrogels based on polycaprolactone (PCL) hydrogels and carboxyl-capped aniline pentamer (CCAP) were synthesized by a simple coupling reaction at room temperature. The reaction was carried out between the hydroxyl groups of hydroxyethylmethacrylate in a photopolymerized glycidyl methacrylate (GMA)-functionalized PCL-poly(ethylene glycol)-PCL degradable network and carboxyl group of CCAP, using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as water-condensing agent and 4-dimethylamino-pyridine as catalyst. The electroactivity of the hydrogels was verified by cyclic voltammetry, which showed three pairs of redox peaks. The electrical conductivities and swelling ratios of these hydrogels were controlled by the CCAP content, the poly(ethylene glycol) molecular weight in the macromer, and the crosslinking density of the hydrogels.

  • 19. Hao, X. J.
    et al.
    Nilsson, Camilla
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Jesberger, M.
    Stenzel, M. H.
    Malmström, Eva
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Davis, T. P.
    Östmark, Emma
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Barner-Kowollik, C.
    Dendrimers as scaffolds for multifunctional reversible addition-fragmentation chain transfer agents: Syntheses and polymerization2004In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 42, no 23, p. 5877-5890Article in journal (Refereed)
    Abstract [en]

    The synthesis and characterization of novel first- and second-generation true dendritic reversible addition-fragmentation chain transfer (RAFT) agents carrying 6 or 12 pendant 3-benzylsulfanylthiocarbonylsulfanylpropionic acid RAFT end groups with Z-group architecture based on 1,1,1-hydroxyphenyl ethane and trimethylolpropane cores are described in detail. The multifunctional dendritic RAFT agents have been used to prepare star polymers of poly(butyl acrylate) (PBA) and polystyrene (PS) of narrow polydispersities (1.4 < polydispersity index < 1.1 for PBA and 1.5 < polydispersity index < 1.3 for PS) via bulk free-radical polymerization at 60 degreesC. The novel dendrimer-based multifunctional RAFT agents effect an efficient living polymerization process, as evidenced by the linear evolution of the number-average molecular weight (M.) with the monomer-polymer conversion, yielding star polymers with molecular weights of up to M-n = 160,000 g mol(-1) for PBA (based on a linear PBA calibration) and up to M. = 70,000 g mol(-1) for PS (based on a linear PS calibration). A structural change in the chemical nature of the dendritic core (i.e., 1,1,1-hydroxyphenyl ethane vs trimethylolpropane) has no influence on the observed molecular weight distributions. The star-shaped structure of the generated polymers has been confirmed through the cleavage of the pendant arms off the core of the star-shaped polymeric materials.

  • 20.
    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.

  • 21.
    Hed, Yvonne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Zhang, Yuning
    Andrén, Olver C. J.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Zeng, Xianghui
    Nyström, Andreas M.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Side-by-side comparison of dendritic-linear hybrids and their hyperbranched analogs as micellar carriers of chemotherapeutics2013In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 51, no 19, p. 3992-3996Article in journal (Refereed)
    Abstract [en]

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

  • 22. Hietala, Sami
    et al.
    Nyström, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Tenhu, Heikki
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Solution Properties of Dendronized Poly(Hydroxy Ethyl Methacrylate) Polymers2006In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 44, no 11, p. 3674-3683Article in journal (Refereed)
    Abstract [en]

    Four generations of dendronized polymers with a methacrylate backbone and hydroxy-functionalized aliphatic polyester dendrons based on 2,2-bis(methylol)propionic acid were studied in solutions by rheological measurements, dynamic light scattering, turbidimetry, and H-1 NMR self-diffusion measurements to reveal the effect of increasing hydrophilicity and molecular size on their solution properties. The studied polymers were interesting new amphiphiles with a hydrophobic main chain and a hydrophilic shell. Evidence of aggregation upon the heating of the first-generation polymer in an aqueous solution was obtained by dynamic light scattering and turbidimetry, reflecting the effect of the hydrophobic polymer backbone, whereas the higher generation polymers did not show aggregation upon heating. Although the dimensions of the polymers were observed to increase with increasing generation, all the polymers exhibited low viscosities and Newtonian flow behavior in both aqueous and dimethyl sulfoxide solutions. The relative viscosities of the polymers in water and dimethyl sulfoxide showed that the conformation of the polymers was somewhat more open in dimethyl sulfoxide, and this led to higher viscosities than those in water, in agreement with the H-1 NMR diffusion measurements, by which the dimensions were found to be larger for the polymers dissolved in dimethyl sulfoxide.

  • 23.
    Hua, Geng
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Johan, Franzén
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    One-pot inimer promoted ROCP synthesis of branched copolyesters using α-hydroxy-γ-butyrolactone as the branching reagent2016In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 54, no 13, p. 1908-1918Article in journal (Refereed)
    Abstract [en]

    An array of branched poly(ɛ-caprolactone)s was successfully synthesized using an one-pot inimer promoted ring-opening multibranching copolymerization (ROCP) reaction. The biorenewable, commercially available yet unexploited comonomer and initiator 2-hydroxy-γ-butyrolactone was chosen as the inimer to extend the use of 5-membered lactones to branched structures and simultaneously avoiding the typical tedious work involved in the inimer preparation. Reactions were carried out both in bulk and in solution using stannous octoate (Sn(Oct)2) as the catalyst. Polymerizations with inimer equivalents varying from 0.01 to 0.2 were conducted which resulted in polymers with a degree of branching ranging from 0.049 to 0.124. Detailed ROCP kinetics of different inimer systems were compared to illustrate the branch formation mechanism. The resulting polymer structures were confirmed by 1H, 13C, and 1H-13C HSQC NMR and SEC (RI detector and triple detectors). The thermal properties of polymers with different degree of branching were investigated by DSC, confirming the branch formation. Through this work, we have extended the current use of the non-homopolymerizable γ-butyrolactone to the branched polymers and thoroughly examined its behaviors in ROCP.

  • 24.
    Höglund, Anders
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Spontaneous Crosslinking of Poly(1,5-dioxepan-2-one) Originating from Ether Bond Fragmentation2008In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 46, no 21, p. 7258-7267Article in journal (Refereed)
    Abstract [en]

    The spontaneous reaction of unsaturated double bonds induced by the fragmentation of ether bonds is presented as a method to obtain a crosslinked polymer material. Poly(1,5-dioxepan-2-one) (PDXO) was synthesized using three different polymerization techniques to investigate the influence of the synthesis conditions on the ether bond fragmentation. It was found that thermal fragmentation of the ether bonds in the polymer main chain occurred when the synthesis temperature was 140 degrees C or higher. The double bonds produced reacted spontaneously to form cross-links between the polymer chains. The formation of a network structure was confirmed by Fourier transform infrared spectrometry and differential scanning calorimetry. In addition, the low molar mass species released during hydrolysis of the DXO polymers were monitored by ESI-MS and MALDI-TOF-MS. Ether bond fragmentation also occurred during the ionization in the electrospray instrument, but predominantly in the lower mass region. No fragmentation took place during MALDI ionization, but it was possible to detect water-soluble DXO oligomers with a molar mass up to approximately 5000 g/mol. The results show that ether bond fragmentation can be used to form a network structure of PDXO.

  • 25.
    Höglund, Anders
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kowalczuk, Marek
    Centre of Polymer and Carbon Materials, Polish Academy of Sciences.
    Adamus, Grazyna
    Centre of Polymer and Carbon Materials, Polish Academy of Sciences.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Fingerprinting the degradation product patterns of different polyester-ether networks by electrospray ionization mass spectrometry2008In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 46, no 13, p. 4617-4629Article in journal (Refereed)
    Abstract [en]

    Fingerprinting of the degradation product patterns by electrospray ionization mass spectrometry (ESI-MS) was evaluated as a tool to monitor the degree of degradation in polyester-ether networks. Four different crosslinked caprolactone (CL) and/ or 1,5-dioxepan-2-one (DXO) networks were subjected to hydrolytic degradation in aqueous solution at 37 degrees C for up to 147 days. After predetermined time periods, the water-soluble degradation products were analyzed by ESI-MS and tandem ESI-MS. In addition, changes in pH, mass loss, and copolymer composition were determined. In the case of more slowly hydrolyzed CL-rich (co)polymers, CL and/or DXO oligomers terminated by hydroxyl and carboxyl end groups were predominantly formed as degradation products. However, on prolonged hydrolysis oligomers with attached crosslinking agent dominated the degradation product patterns of more easily hydrolyzed DXO-rich (co)polymers. It was shown that in the recorded mass spectra the variation of intensities in the series of ions corresponding to DXO and CL/DXO oligomers with or without attached crosslinking agent could be utilized to monitor the extent of hydrolytic degradation in the polyester matrix and the disruption of the network structure.

  • 26.
    Imam, Mohammad
    et al.
    University of Pennsylvania.
    Peterca, Mihai
    Univeristy of Pennsylvania.
    Edlund, Ulrica
    University of Pennsylvania.
    Balagurusamy, Venkatachalapathy
    University of Pennsylvania.
    Percec, Virgil
    University of Pennsylvania.
    Dendronized Supramolecular Polymers Self-Assembled from Dendritic Ionic Liquids2009In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 47, no 16, p. 4165-4193Article in journal (Refereed)
    Abstract [en]

    The synthesis, structural, and retrostructural analysis of a library of self-assembling dendrons containing triethyl and tripropyl ammonium, pyridinium and 3-methylimidazolium chloride, tetrafluoroborate, and hexafluorophosphate at their apex are reported. These dendritic ionic liquids self-assemble into supramolecular columns or spheres which self-organize into 21) hexagonal or rectangular and 31) cubic or tetragonal liquid crystalline and crystalline lattices. Structural analysis by X-ray diffraction experiments demonstrated the self-assembly of supramolecular dendrimers containing columnar and spherical nanoscale ionic liquid reactors segregated in their core. Both in the supramolecular columns and spheres the noncovalent interactions mediated by the ionic liquid provide a supramolecular polymer and therefore, these assemblies represent a new class of dendronized supramolecular polymers.

  • 27.
    Ingverud, Tobias
    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.
    Larsson, Emma
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Hemmer, Guillaume
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Rojas, Ramiro
    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.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    High water-content thermoresponsive hydrogels via electrostatic macrocrosslinking of cellulose nanofibrils2016In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 54, no 21, p. 3415-3424Article in journal (Refereed)
    Abstract [en]

    Atom transfer radical polymerization (ATRP) has been utilized to synthesize tri- and star-block copolymers of poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) and quaternized poly(2-(dimethylamino)ethyl methacrylate) (qPDMAEMA). The block copolymers, all with a minimum of two cationically charged blocks, were sequentially used for electrostatic macrocrosslinking of a dilute dispersion of anionic TEMPO-oxidized cellulose nanofibrils (CNF, 0.3 wt%), forming free-standing hydrogels. The cationic block copolymers adsorbed irreversibly to the CNF, enabling the formation of ionically crosslinked hydrogels, with a storage modulus of up to 2.9 kPa. The ability of the block copolymers to adsorb to CNF was confirmed by quartz crystal microbalance with dissipation monitoring (QCM-D) and infrared spectroscopy (FT-IR), and the thermoresponsive properties of the hydrogels were investigated by rheological stress and frequency sweep, and gravimetric measurements. This method was shown to be promising for the facile production of thermoresponsive hydrogels based on CNF.

  • 28. Jesberger, M.
    et al.
    Barner, L.
    Stenzel, M. H.
    Malmström, Eva E
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Davis, T. P.
    Barner-Kowollik, C.
    Hyperbranched polymers as scaffolds for multifunctional reversible addition-fragmentation chain-transfer agents: A route to polystyrene-core-polyesters and polystyrene-block-poly(butyl acrylate)-core-polyesters2003In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, no 23, p. 3847-3861Article in journal (Refereed)
    Abstract [en]

    Polydisperse hyperbranched polyesters were modified for use as novel multifunctional reversible addition-fragmentation chain-transfer (RAFT) agents. The polyester-core-based RAFT agents were subsequently employed to synthesize star polymers of n-butyl acrylate and styrene with low polydispersity (polydispersity index < 1.3) in a living free-radical process. Although the polyester-core-based RAFT agent mediated polymerization of n-butyl acrylate displayed a linear evolution of the number-average molecular weight (M.) up to high monomer conversions (>70%) and molecular weights [M-n > 140,000 g mol(-1), linear poly(methyl methacrylate) equivalents)], the corresponding styrene-based system reached a maximum molecular weight at low conversions (approximate to30%, M-n = 45,500 g mol(-1), linear polystyrene equivalents). The resulting star polymers were subsequently used as platforms for the preparation of star block copolymers of styrene and n-butyl acrylate with a polyester core with low polydispersities (polydispersity index < 1.25). The generated polystyrene-based star polymers were successfully cast into highly regular honeycomb-structured microarrays.

  • 29. JOHANSSON, M
    et al.
    HULT, A
    INFLUENCE OF ALLYL ETHERS IN COATING RESINS1991In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 29, p. 1639-1644Article in journal (Refereed)
    Abstract [en]

    The effects of allyl ethers in coating resins have been studied in relation to different systems. The details that have been investigated are: the reactions between allyl ethers-styrene-cobalt salt in air, the influence of cobalt salt on oxidized allyl ethers, and the interaction between allyl ethers and maleic esters with respect to copolymerization. The curing rates of allyl functional oligomers as coatings have also been studied. The results are summarized together with the results from a previous article by the same authors to give an overall view of the curing mechanism in allyl ether functional unsaturated polyester resins dissolved in styrene.

  • 30. JOHANSSON, M
    et al.
    HULT, A
    INFLUENCE OF ALLYL ETHERS ON FREE-RADICAL POLYMERIZATION OF STYRENE1991In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 29, p. 9-14Article in journal (Refereed)
    Abstract [en]

    The effect of allyl ethers on the free radical polymerization of styrene has been studied with respect to chain transfer, copolymerization, and conversion. The studies have been performed in an inert atmosphere or in air. Six different allyl ethers have been used as model substances in order to show the effect of structural differences of the ethers on the polymerization. Contrary to what was expected, no chain transfer through hydrogen abstraction was found. Nor did any copolymerization occur. When the polymerization was performed in air, the allyl ethers had a retarding effect on the polymerization rate, due to oxidation of the allyl ethers. The oxidation rate of the allyl ethers was found to be related to their structure, where the functionality and presence of intramolecular hydrogen bonding are the main factors.

  • 31.
    JOHANSSON, M
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    MALMSTROM, E
    HULT, A
    SYNTHESIS, CHARACTERIZATION, AND CURING OF HYPERBRANCHED ALLYL ETHER MALEATE FUNCTIONAL ESTER RESINS1993In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 31, p. 619-624Article in journal (Refereed)
    Abstract [en]

    A model two-step synthesis of a saturated hyperbranched hydroxyl-terminated ester has been developed to show a synthesis route. Three different series of hyperbranched esters with different terminations have been synthesized to relate some of their properties to their structures. This route has then been used to synthesize three different allyl ether-maleate functional hyperbranched ester resins in a two-step procedure. The resins have been characterized with respect to rheology, structure, and properties, and the differences are discussed. The allyl ether-maleate functional resins have also been studied with respect to curing performance and final film properties.

  • 32. JOHANSSON, M
    et al.
    TROLLSAS, M
    HULT, A
    SYNTHESIS, CHARACTERIZATION, AND CURING OF WELL-DEFINED ALLYL ETHER-MALEATE FUNCTIONAL ESTER OLIGOMERS - LINEAR VERSUS NONLINEAR STRUCTURES1992In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 30, p. 2203-2210Article in journal (Refereed)
    Abstract [en]

    A series of allyl ether-maleate functional star-shaped esters with from one to four arms has been synthesized. The structures that have been made are an analogous series with increasing molecular weight and functionality where the increase in molecular weight has been made nonlinear, i.e., star-shaped. The resins are monodisperse in the sense that each arm has a well-defined structure and that, within a certain sample, only one type of molecule exists. The viscosity and rheological behavior of the resins have been studied. The curing kinetics of the star-shaped (branched) resins and the properties of the films formed have also been studied. These properties have been related to differences in functionality and to differences in the molecular architecture of the resins.

  • 33. Johansson, Mats
    et al.
    Hult, Anders
    INFLUENCE OF ALLYL ETHERS IN COATING RESINS1991In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 29Article in journal (Refereed)
  • 34. Johansson, Mats
    et al.
    Hult, Anders
    INFLUENCE OF ALLYL ETHERS ON FREE-RADICAL POLYMERIZATION OF STYRENE1991In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 29Article in journal (Refereed)
  • 35. Khan, Anzar
    et al.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Montague, Martha F.
    Hawker, Craig J.
    Synthesis and characterization of hyperbranched polymers with increased chemical versatility for imprint lithographic resists2008In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 46, no 18, p. 6238-6254Article in journal (Refereed)
    Abstract [en]

    Hyperbranched polymers were prepared from a variety of mono- and difunctional monomers and used in the development of novel UV-imprint lithography (UV-IL) resists. The unique physical and chemical properties of these hyperbranched materials significantly increase the range of molecular systems that could be imprinted. Traditional challenges, such as the use of monomers that have low boiling points or the use of insoluble/highly crystalline momomers, are overcome by the preparation of hyperbranched polymers that incorporate these repeat units. In addition, the low viscosity of the hyperbranched macromolecules and the large number of reactive chain ends overcome many difficulties that are traditionally associated with the use of polymeric materials as imprint resists. Hyperbranched polymers containing up to 12 mol % pendant vinyl groups, needed for secondary crosslinking during imprinting, were prepared with a wide range of repeat unit structures and successfully imprinted with features from tens of microns to similar to 100 nm.

  • 36. Liu, Y.
    et al.
    Lindblad, M. S.
    Ranucci, E.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    New segmented poly(ester-urethane)s from renewable resources2001In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 39, no 5, p. 630-639Article in journal (Refereed)
    Abstract [en]

    The physical and mechanical properties of aliphatic homopolyesters from monomers obtainable from renewable resources, namely, 1,3-propanediol and succinic acid, were improved by their combination with aromatic urethane segments capable of establishing strong intermolecular hydrogen bonds. Segmented poly(ester-urethane)s were synthesized from dihydroxy-terminated oligo(propylene succinate)s chain-extended with 4,4'-diisophenylmethane diisocyanate. The newly synthesized materials were exhaustively characterized by H-1 NMR spectroscopy, size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, and with respect to their main static mechanical properties, an Instron apparatus was used. The average repeat number of the hard segments, evaluated by NMR, ranged from 4 to 9, whereas that of the flexible segments was about 14. The degree of crystallinity, glass-transition temperature, melting point, tensile strength, elongation, and Young's modulus were influenced by the ratio between hard and soft segments of the segmented copolymer in a predictable way. The results demonstrated that poly(ester-urethane)s from 1,3-propanediol and succinic acid are promising thermoplastics.

  • 37. Liu, Y.
    et al.
    Ranucci, E.
    Lindblad, M. S.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    New biodegradable polymers from renewable sources: Polyester-carbonates based on 1,3-Propylene-co-1,4-cyclohexanedimethylene succinate2001In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 39, no 14, p. 2508-2519Article in journal (Refereed)
    Abstract [en]

    alpha,omega -Dihydroxy-terminated copolymeric oligomers of a 1,3-propylene/1,4-cyclohexanedimethylene succinate structure were obtained by the thermal polycondensation of 1,3-propanediol/1,4-cyclohexanedimethanol/s acid mixtures. They were subsequently chain-extended via phosgene synthesis to high molecular weight aliphatic/alicyclic copolyester-carbonates. These new polymers, besides having a biodegradable backbone, originate from two monomers, namely, 1,3-propanediol and succinic acid, which can be obtained by renewable sources. Therefore, they have a potential as environmentally friendly materials. All synthesized materials were characterized in reference to their molecular structure by H-1 NMR and C-13 NMR. Their molecular weights and molecular weight distributions were determined by size exclusion chromatography, and their main thermal properties were measured by DSC. Spectroscopic characterizations were in full agreement with the proposed structures. 1,4-Cyclohexanedimethanol was used as a diol comonomer to improve the overall thermal properties of poly(1,3-propylene succinate). The results of the characterization performed show that the initial expectations were only partially satisfied.

  • 38. Lo Conte, Mauro
    et al.
    Robb, Maxwell J.
    Hed, Yvonne
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Marra, Alberto
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hawker, Craig J.
    Dondoni, Alessandro
    Exhaustive Glycosylation, PEGylation, and Glutathionylation of a [G4]-ene(48) Dendrimer via Photoinduced Thiol-ene Coupling2011In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 49, no 20, p. 4468-4475Article in journal (Refereed)
    Abstract [en]

    The use of free-radical thiol-ene coupling (TEC) for the introduction of carbohydrate, poly(ethylene glycol), and peptide fragments at the periphery of an alkene functional dendrimer has been reported in this article. Four different sugar thiols including glucose, mannose, lactose, and sialic acid, two PEGylated thiols, and the natural tripeptide glutathione were reacted with a fourth generation alkene functional dendrimer [G4]-ene(48) on irradiation at lambda(max) 365 nm. In all cases, the (1)H NMR spectra of the crude reaction mixture revealed the complete disappearance of alkene proton signals indicating the quantitative conversion of all 48 alkene groups of the dendrimer. With one exception only, all dendrimer conjugates were isolated in high yields (70-94%), validating the high efficiency of multiple TEC reactions on a single substrate. All isolated and purified compounds were analyzed by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) spectrometry and gave spectra consistent with the assigned structure.

  • 39.
    Malkoch, Michael
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Claesson, Hans
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Löwenhielm, Peter
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Synthesis and characterization of 2,2-bis(methylol)propionic acid dendrimers with different cores and terminal groups2004In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 42, no 7, p. 1758-1767Article in journal (Refereed)
    Abstract [en]

    Three sets of aliphatic polyester dendrimers based on 2,2-bis(methylol)propionic acid (bis-MPA) were synthesized. Two of the sets had benzylidene terminal groups and either a trimethylolpropane or triphenolic core moiety. The last set had acetonide terminal groups and a triphenolic core moiety. Benzylidene-[G#1]-anhydride and acetonide-[G#1] -anhydride were used as the reactive building blocks in the construction of all dendrimers. The large excess of building blocks used in the coupling reactions initially resulted in considerable material loss. This waste was eliminated through the development of a recycling method. H-1 and C-13 NMR and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis were used to verify the purity of all compounds. Size exclusion chromatography (SEC) was used, as well as MALDI-TOF, for molecular weight determinations. The SEC measurements were conducted with a universal calibration method and an online right-angle laser light scattering detector. Measured dendrimer molecular weights were close to their theoretical molar masses. Observations were also made of the hydrodynamic radius and intrinsic viscosity for the different dendrimers.

  • 40.
    Martin-Serrano Ortiz, Angela
    et al.
    IBIMA Reg Univ Hosp Malaga UMA, Hosp Civil, Res Lab, Plaza Hosp Civil, Malaga 29009, Spain.;IBIMA Reg Univ Hosp Malaga UMA, Hosp Civil, Allergy Unit, Plaza Hosp Civil, Malaga 29009, Spain.;BIONAND Andalusian Ctr Nanomed & Biotechnol, Parque Tecnol Andalucia, Malaga 29590, Spain..
    Stenström, Patrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Antunez, Pablo Mesa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Andrén, Oliver C. J.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Torres, Maria J.
    IBIMA Reg Univ Hosp Malaga UMA, Hosp Civil, Res Lab, Plaza Hosp Civil, Malaga 29009, Spain.;IBIMA Reg Univ Hosp Malaga UMA, Hosp Civil, Allergy Unit, Plaza Hosp Civil, Malaga 29009, Spain.;BIONAND Andalusian Ctr Nanomed & Biotechnol, Parque Tecnol Andalucia, Malaga 29590, Spain..
    Montanez, Maria I.
    IBIMA Reg Univ Hosp Malaga UMA, Hosp Civil, Res Lab, Plaza Hosp Civil, Malaga 29009, Spain.;IBIMA Reg Univ Hosp Malaga UMA, Hosp Civil, Allergy Unit, Plaza Hosp Civil, Malaga 29009, Spain.;BIONAND Andalusian Ctr Nanomed & Biotechnol, Parque Tecnol Andalucia, Malaga 29590, Spain..
    Malkoch, Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Design of multivalent fluorescent dendritic probes for site-specific labeling of biomolecules2018In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 56, no 15, p. 1609-1616Article in journal (Refereed)
    Abstract [en]

    Herein, the synthesis and characterization of orthogonal dendrons decorated with multiple units of fluorescent and a chemoselective group at a focal point, followed by specific antibody labeling, is presented. Fluorescence results confirm the applicability of the fluorescent probes for biomolecule labeling and fluorescent signal amplification.

  • 41.
    Mongkhontreerat, Surinthra
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Andrén, Oliver C. J.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Boujemaoui, Assya
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Dendritic hydrogels: From exploring various crosslinking chemistries to introducing functions and naturally abundant resources2015In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 53, no 21, p. 2431-2439Article in journal (Refereed)
    Abstract [en]

    Dendritic hydrogels from dendritic-linear-dendritic (DLD) block copolymers based on PEG and bis-MPA dendrons were constructed via UV-initiated thiol-ene, thiol-yne, CuAAC, and amine-NHS crosslinking chemistries. Stoichiometric ratio manipulations, prior to film formation, resulted in functional hydrogels with tuneable compressive moduli. The highest gel fractions for all networks were obtained at off-stoichiometric ratios with surplus of DLDs. Finally, sustainable networks were fabricated by amalgamating DLD, naturally abundant cellulose nanocrystal, and protein-based bovine serum albumin.

  • 42.
    Målberg, Sofia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Basalp, Dildare
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Finne Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Bio-Safe Synthesis of Linear and Branched PLLA2010In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 48, no 5, p. 1214-1219Article in journal (Refereed)
    Abstract [en]

    The catalytic activities of Bi(III) acetate (Bi(OAc)(3)) and of creatinine towards the ring-opening polymerization of L-lactide have been compared with those of a stannous (II) ethylhexanoate ((SnOct)(2))-based system and with those of a system catalyzed by enzymes. All four were suitable catalysts for the synthesis of high and moderate molecular weight poly(L-lactide)s and the differences in reactivity and efficiency have been studied. Linear and branched poly(L-lactide)s were synthesized using these bio-safe initiators together with ethylene glycol, pentaerythritol, and myoinositol as coinitiators. The polymerizations were performed in bulk at 120 and 140 degrees C and different reactivities and molecular weights were achieved by adding different amounts of coinitiators. A molecular weight of 105,900 g/mol was achieved with 99% conversion in 5 h at 120 degrees C with a Bi(OAc)(3)-based system. This system was comparable to Sn(Oct)(2) at 140 degrees C. The reactivity of creatinine is lower than that of Bi(OAc)(3) but higher compared with enzymes lipase PS (Pseudomonas fluorescens). A ratio of Sn(Oct)(2) M-o/I-o 10,000:1 was needed to achieve a polymer with a reasonable low amount of tin residue in the precipitated polymer, and a system catalyzed by creatinine at 140 degrees C has a higher conversion rate than such a system.

  • 43.
    Nilsson, Camilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva E.
    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.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Dendrimers in Thiol-ene Crosslinked Networks and the Effect on Subsequent Generations on Thermoset Properties2009In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 47, no 2, p. 589-601Article in journal (Refereed)
    Abstract [en]

    A series of well-defined allyl-ether functionalized polyester dendrimers has been synthesized via the divergent approach using traditional esterification reactions. Two commercially available trifunctional thiols, trimethylolpropane tri(3-mercaptopropanoate) (TRIS) and ethoxylated trimethylolpropane tri(3-mercaptopropanoate) (ETTMP), were incorporated with the dendrimers into the thiol-ene polymer networks. The thiol-ene reactions were conducted at room temperature and cured by UV light without the addition of photoinitiatior. Highly crosslinked films were obtained and characterized with respect to mechanical (DMA) and thermal (DSC and TGA) properties.

  • 44.
    Nilsson, Camilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva E.
    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.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Methacrylated Dendrimers in Thiol-Methacrylate Networks and the Effect of Conversion on the Thermoset Properties2009In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 47, no 21, p. 5815-5826Article in journal (Refereed)
    Abstract [en]

    A series of well-defined methacrylate-functionalized polyester dendrimers based on 2,2-bis(methylol)propionic acid (bis-MPA) has been synthesized divergently. The thermal properties and conversion of the methacrylate functional dendrimers are investigated along with the structure-property relationship of networks composed of the methacrylate dendrimers and two commercially available trifunctional thiols, trimethylolpropane tri(3-mercaptopropanoate) (TRIS) and ethoxylated trimethylolpropane tri(3-mercaptopropanoate) (ETTMP). The thiol-methacrylate reactions were conducted at room temperature, under ambient conditions, and triggered by UV light in the presence of a photoinitiator. Crosslinked films were obtained and characterized with respect to conversion (FT-Raman) and thermal (DSC and TGA) properties.

  • 45.
    Nilsson, Camilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Simpson, Neil
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malkoch, Michael
    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.
    Malmström, Eva E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Synthesis and Thiol-Ene Photopolymerization of Allyl Ether Functionalized Dendrimers2008In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 46, no 4, p. 1339-1348Article in journal (Refereed)
    Abstract [en]

    Well-defined, allyl-ether functional, first-generation dendrimers have been synthesized. The convergent growth approach was utilized, using the anhydride of the allyl-ether terminated building block. Three different core moieties were used: trimethylolpropane, trisphenol, and ditrimethylolpropane. The coupling reactions proceeded in good yields and all compounds were characterized by NMR, MALDI-TOF, and SEC. The allyl-terminated dendrimers were crosslinked by thiol-ene chemistry, using a multifunctional thiol, TriThiol, to give clear and smooth films. The photopolymerization was conducted in the presence of a photoinitiator, Irgacure 651, and no traces of either allyl-ether groups or thiols were observed by FT-Raman after cure. All crosslinked films were characterized with respect to mechanical (DMA) and thermal (DSC) properties. It was found that homogeneous networks were formed and that the core functionality and structure had little effect on the network properties.

  • 46.
    Nyström, Andreas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Furo, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Malmström, Eva
    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.
    Bulk Properties of Dendronized Polymers with Tailored End-groups emanating from the same Backbone2005In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 43, no 19, p. 4496-4504Article in journal (Refereed)
    Abstract [en]

    Dendronized polymers with a methacrylate backbone bearing pendant aliphatic polyester dendrons based on 2,2-bis(methylol)propionic acid have been investigated by rheological measurements, differential scanning calorimetry (DSC), size exclusion chromatography (SEC), and H-1 NMR self-diffusion techniques. The change in material properties due to the attachment of larger dendrons and/or different end-groups to a backbone of the same length is investigated. Dendronized polymers of the second to fourth generation with hydroxyl, acetonide, or hexadecyl end-group functionalities have been studied. DSC revealed that the glass transition temperature of the amorphous polymers increases with increasing size of the dendrons, and that the ability for the hexadecyl functional polymers to crystallize decreases with increasing size of dendrons. H-1 NMR self-diffusion and longitudinal relaxation data are consistent with an elongated rod-like model of the polymers in solution. Larger dendrons lead to a larger rod diameter that approximately double when increasing the generation of dendronized polymer from two to four. Rheological measurements demonstrated that the complex viscosity at low frequency increased with dendron size. Independently of the functionality, the second and third generation samples initially showed a Newtonian plateau, followed by a shear thinning region at higher frequencies. The fourth generation samples only showed shear thinning over the whole frequency region.

  • 47.
    Nyström, Andreas
    et al.
    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.
    Dendronized polymers with tailored surface groups2005In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 43, no 17, p. 3852-3867Article in journal (Refereed)
    Abstract [en]

    A series of polymers tethered with bis-MPA dendrons was synthesized by a combination of divergent growth and atom transfer radical polymerization (ATRP). Macromonomers of first and second generation were synthesized utilizing the acetonide protected anhydride of bis-MPA as the generic esterfication agent. The macromonomers were polymerized in a controlled fashion by ATRP utilizing Cu(I)/Cu(II) and N-propyl-2-pyridylmethanamine as the halogen/ligand system. The end-groups of these polymers were further tailored to achieve hydroxyl, acetate, and aliphatic hexadecyl functionality. With this approach all polymers will emanate from the same backbone, enabling for an evaluation of both the generation and end-group dependent properties. Furthermore, a dendronized tri-block copolymer was synthesized. All materials were analyzed by H-1 and C-13 NMR, as well as size-exclusion chromatography (SEC). The SEC analysis revealed that the molecular weights of the divergently grown dendronized polymers increased with increasing generation while the polydispersity (PDI) was kept low.

  • 48.
    Odelius, Karin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Precision synthesis of microstructures in star-shaped copolymers of epsilon-caprolactone, L-lactide, and 1,5-dioxepan-2-one2008In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 46, no 4, p. 1249-1264Article in journal (Refereed)
    Abstract [en]

    Star-shaped homo- and copolymers were synthesized in a controlled fashion using two different initiating systems. Homopolymers of E-caprolactone, L-lactide, and 1,5-dioxepan-2-one were firstly polymerized using (I) a spirocyclic tin initiator and (II) stannous octoate (cocatalyst) together with pentaerythritol ethoxylate 15/4 EO/OH (coinitiator), to give polymers with identical core moieties. Our gained understanding of the versatile and controllable initiator systems kinetics, the transesterification reactions occurring, and the role which the reaction conditions play on the material outcome, made it possible to tailor the copolymer microstructure. Two strategies were used to successfully synthesize copolymers of different microstructures with the two initiator systems, i.e., a more multiblock- or a block-structure. The correct choice of the monomer addition order enabled two distinct blocks to be created for the copolymers of poly(DXO-co-LLA) and poly(CL-co-LLA). In the case of poly(CL-co-DXO), multiblock copolymers were created using both systems whereas longer blocks were created with the spirocyclic tin initiator.

  • 49.
    Odelius, Karin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Finne, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Versatile and controlled synthesis of resorbable star-shaped polymers using a spirocyclic tin initiator: Reaction optimization and kinetics2006In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 44, no 1, p. 596-605Article in journal (Refereed)
    Abstract [en]

    A spirocyclic tin initiator was synthesized from pentaerythritol ethoxylate and dibutyltin oxide and used to polymerize L-lactide with dichloromethane, chloroform, toluene, and chlorobenzene as solvents. The reactions were performed at different temperatures and it is concluded that neither the temperature nor the solvent affects the molecular weight or the molecular weight distribution of the star-shaped polymers. The reaction rate was significantly increased by raising the reaction temperature or choosing a solvent with a low dielectric constant. All polymers showed a molecular-weight distribution below 1.19 and a molecular-weight determined by the initial monomer to initiator concentration ([M](0)/[1]). No induction period was seen for the polymerizations. They were all first order in initiator and the degree of aggregation in toluene at 110 degrees C was found to be 4/5. The glass transition temperature and the melting temperature of the star-shaped polymers increase with increasing arm length.

  • 50.
    Olofsson, Kristina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malkoch, Michael
    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.
    Facile Synthesis of Dopa-Functional Polycarbonates viaThiol-Ene-Coupling Chemistry towards Self-Healing Gels2016In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 54, no 15, p. 2370-2378Article in journal (Refereed)
    Abstract [en]

    Since extraction of the naturally occurring mussel-foot proteins is expensive and time-consuming, routes towards synthetic analogues are continuously being explored. Often, these methods involve several protection and deprotection steps, making the synthesis of synthetic analogues time-consuming and expensive as well. Herein, we show that UV-initiated thiol-ene coupling between a thiol-functional dopamine derivative and an allyl-functional aliphatic polycarbonate can be used as a fast and facile route to dopa-functional materials. Different thiol-to-allyl ratios and irradiation protocols were used and it was found that nearly 50% of the allyl groups could be functionalized with dopa within short reaction times, without the need of protecting the catechol. It is also demonstrated herein that the dopa-functional polymers can be used to form self-healing gels through complexation with Fe3+ ions at increased pH.

12 1 - 50 of 78
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