The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Dominique Teyssie - One of the best experts on this subject based on the ideXlab platform.
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immobilization of Polyisobutene in semi interpenetrating polymer network architecture
Polymer, 2010Co-Authors: Benjamin Davion, Odile Fichet, Cedric Vancaeyzeele, Dominique TeyssieAbstract:The entrapment of linear Polyisobutene (PIB) in semi-IPN architecture is shown to be as efficient as it is in cross-linkable telechelic PIB based full IPN architectures as far as the suppression of cold flow is concerned. Indeed, homogeneous linear PIB/cross-linked polycyclohexylmethacrylate (PCHMA) semi-IPNs containing from 20 to 70 wt% PIB and synthesized without solvent show no cold flow and higher mechanical properties than those of linear PIB or 50 wt% PIB containing blend. In addition, the particular barrier properties toward gas and water are preserved. Those properties arise from the phase co-continuity morphology of the semi-IPN materials which moreover compares with that of corresponding IPNs. A systematic study of the synthesis conditions (nature of the initiator, temperature, cross-linking density) showed that the reacting mixture viscosity is an important parameter that controls the phase separation degree in the final material.
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Polyisobutene polycyclohexyl methacrylate interpenetrating polymer networks
Polymer, 2006Co-Authors: Cedric Vancaeyzeele, Odile Fichet, Sylvie Boileau, Battatchona Amana, Dominique TeyssieAbstract:Abstract Interpenetrating polymer networks (IPNs) combining Polyisobutene (PIB) and poly(cyclohexyl methacrylate) (PCHMA) networks were prepared using an in situ strategy. PIB networks were formed by alcohol–isocyanate addition between the hydroxyl end groups of telechelic dihydroxyPolyisobutene and an isocyanate cross-linker, catalyzed by dibutyltindilaurate (DBTDL). PCHMA networks were obtained from free-radical copolymerization of cyclohexyl methacrylate (CHMA) with ethylene glycol bismethacrylate (EGDM) in the presence of dicyclohexyl peroxydicarbonate (DCPD) as the initiator. The network formations into the IPN architecture were followed by FTIR spectroscopy. In a large composition range, transparent IPNs exhibit two mechanical relaxation temperatures as determined by dynamic mechanical thermal analysis (DMTA), corresponding to those of a PIB enriched phase and of one interpenetrating phase containing the PCHMA network. This morphology was confirmed by IPN surface analysis by AFM. As expected, mechanical properties of PIB networks are improved by the presence of PCHMA network in such IPN architectures.
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Polyisobutene polystyrene interpenetrating polymer networks effects of network formation order and composition on the ipn architecture
Polymer, 2006Co-Authors: Cedric Vancaeyzeele, Odile Fichet, Sylvie Boileau, Judith Laskar, Dominique TeyssieAbstract:Abstract In order to improve Polyisobutene (PIB) mechanical properties, a PIB network is combined with a polystyrene (PS) one into an interpenetrating polymer network (IPN) architecture. PIB network is formed by alcohol addition between the hydroxyl end groups of a telechelic dihydroxy-Polyisobutene and a pluri-isocyanate. PS network is synthesized by free-radical copolymerization of styrene with divinylbenzene. Thus, the optimal synthesis conditions are determined by FTIR spectroscopy and the kinetics of the alcohol–isocyanate addition is studied in detail. A short kinetic study of the PS network formation inside the PIB network is also carried out. The highest degree of interpenetration is obtained by forming the PIB network first. The corresponding transparent IPNs exhibit two mechanical relaxations corresponding to those of PS and PIB enriched phases. However, mechanical properties of PIB networks are tremendously improved by the presence of a PS network in such IPN architectures.
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Polyisobutene poly methylmethacrylate interpenetrating polymer networks synthesis and characterization
Polymer, 2005Co-Authors: Cedric Vancaeyzeele, Odile Fichet, Sylvie Boileau, Dominique TeyssieAbstract:Abstract Interpenetrating polymer networks (IPNs) combining Polyisobutene (PIB) and poly(methyl methacrylate) (PMMA) networks were prepared using a in situ strategy. PIB networks were formed by isocyanate—alcohol addition between the hydroxyl end groups of telechelic dihydroxy-Polyisobutene and an isocyanate cross-linker, catalyzed by dibutyltindilaurate (DBTDL). PMMA networks were obtained from free-radical co-polymerization of methyl methacrylate (MMA) with ethylene glycol bismethacrylate (EGDM) in the presence of dicyclohexyl peroxydicarbonate (DCPD) as the initiator. The synthesis of each network during the IPN formation was followed by FTIR spectroscopy. The highest degree of interpenetration is obtained by forming the PIB network first. The corresponding transparent IPNs exhibit two mechanical relaxation temperatures as determined by Dynamic mechanical thermal analysis (DMTA), corresponding to those of PMMA and PIB enriched phases. Mechanical properties of PIB networks are tremendously improved by the presence of PMMA network in such IPN architecture.
B W Brooks - One of the best experts on this subject based on the ideXlab platform.
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phase behaviour of a non ionic surfactant polymeric solution water system during the phase inversion process
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2005Co-Authors: F Xie, B W BrooksAbstract:Abstract A phase inversion method for making colloidal polymer composites is being considered. That method requires the formation of fine and stable emulsions of polymerisable monomer containing another kind of polymer. Suitable emulsions might be produced via phase inversion. Therefore, the phase behaviour of dispersions containing non-ionic surfactant, non-aqueous polymer solutions (Polyisobutene in styrene) and was investigated. Phase inversion maps, showing the behaviour of the emulsion system as a function of hydrophilic–lipophilic balance (HLB) and water volume fraction, are developed. Two types of non-ionic surfactants, polyoxyethylene sorbitanmonolaurate (SML), or polyoxyethylene nonylphenyl ether (NPE), were used in the study. There are two types of phase inversion (catastrophic and transitional) and, in some circumstances, complex drops may be formed. Five phase inversion boundaries have been found in the NPE system. These include one transitional inversion boundary and four catastrophic inversion boundaries. Unlike the NPE system, there are two transitional phase inversion boundaries in the SML system. With the non-aqueous solutions used here, a stable polymer emulsion with sub-micron polymer drops could not be produced by using the transitional inversion route with either surfactant. However, it was possible to produce a stable polymer emulsion with sub-micron drops by approaching the catastrophic inversion condition. A drop size of about 500 nm was obtained by using a mixture of SML surfactants. As the “unstable” catastrophic inversion region is approached closely, the complex drops increased in size and became less stable.
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polymerisation of styrene emulsified by phase inversion in the presence of Polyisobutene
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2004Co-Authors: F Xie, B W BrooksAbstract:Abstract An attempt has been made to synthesise water-borne polymer composites using a new method. Polyisobutene was dissolved in styrene and an emulsion was formed by phase inversion. Polystyrene was then generated in the drops by polymerisation of the styrene using an oil-soluble initiator. The effects of changes in the Polyisobutene concentration, the initiator concentration, the surfactant concentration and the oil–water ratio on the polymerisation system were investigated. The polymerisation rate increased with increasing initiator concentration, decreasing Polyisobutene concentration, increasing surfactant concentration and increasing water to oil ratio. The average particle size decreased gradually during the polymerisation. The final average particle size decreased with increasing the concentration of surfactant. However, the ratio of water to oil, the initiator concentration and the Polyisobutene concentration had little effect on the final latex particles size. Although, oil drops were transformed into composite particles, new polystyrene particles were also generated in the aqueous phase.
Akikazu Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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Sequence-Controlled Radical Copolymerization of N‑Substituted Maleimides with Olefins and Polyisobutene Macromonomers To Fabricate Thermally Stable and Transparent Maleimide Copolymers with Tunable Glass Transition Temperatures and Viscoelastic Properties
2016Co-Authors: Miki Hisano, Kyota Takeda, Tsutomu Takashima, Zhengzhe Jin, Akira Shiibashi, Akikazu MatsumotoAbstract:Thermally stable and transparent polymers were synthesized by the sequence-controlled radical copolymerization of N-substituted maleimides (RMIs) with various olefins as well as Polyisobutene (PIB) macromonomers. The copolymerization behavior significantly depended on the olefin structures, leading to the formation of AB-alternating and AAB-periodic (2:1 sequence-controlled) copolymers. The sequence-controlled radical copolymerization mechanism was discussed based on the monomer reactivity ratios, which were determined using terminal and penultimate unit models for the copolymerization systems investigated in this study as well as in the literature. The olefin comonomers were classified into several groups according to the copolymerization fashions under the terminal and penultimate unit controls and their conjugated structure and the steric bulkiness of the substituents. The copolymers exhibited excellent thermal properties; the onset temperatures of the resulting copolymers were higher than 300 °C, and the glass transition temperature (Tg) values varied over the temperature range of −68 to 210 °C, depending on the structure of the N- and α-substituents of the comonomer repeating units. The introduction of sterically hindered substituents increased the Tg values, while the introduction of the PIB segments as the side chain of the copolymers resulted in a significant decrease in the Tg value and unique fluidity. The optical and viscoelastic properties of the high-Tg copolymers were investigated
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sequence controlled radical copolymerization of n substituted maleimides with olefins and Polyisobutene macromonomers to fabricate thermally stable and transparent maleimide copolymers with tunable glass transition temperatures and viscoelastic properties
Macromolecules, 2013Co-Authors: Miki Hisano, Kyota Takeda, Tsutomu Takashima, Zhengzhe Jin, Akira Shiibashi, Akikazu MatsumotoAbstract:Thermally stable and transparent polymers were synthesized by the sequence-controlled radical copolymerization of N-substituted maleimides (RMIs) with various olefins as well as Polyisobutene (PIB) macromonomers. The copolymerization behavior significantly depended on the olefin structures, leading to the formation of AB-alternating and AAB-periodic (2:1 sequence-controlled) copolymers. The sequence-controlled radical copolymerization mechanism was discussed based on the monomer reactivity ratios, which were determined using terminal and penultimate unit models for the copolymerization systems investigated in this study as well as in the literature. The olefin comonomers were classified into several groups according to the copolymerization fashions under the terminal and penultimate unit controls and their conjugated structure and the steric bulkiness of the substituents. The copolymers exhibited excellent thermal properties; the onset temperatures of the resulting copolymers were higher than 300 °C, and ...
Cedric Vancaeyzeele - One of the best experts on this subject based on the ideXlab platform.
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immobilization of Polyisobutene in semi interpenetrating polymer network architecture
Polymer, 2010Co-Authors: Benjamin Davion, Odile Fichet, Cedric Vancaeyzeele, Dominique TeyssieAbstract:The entrapment of linear Polyisobutene (PIB) in semi-IPN architecture is shown to be as efficient as it is in cross-linkable telechelic PIB based full IPN architectures as far as the suppression of cold flow is concerned. Indeed, homogeneous linear PIB/cross-linked polycyclohexylmethacrylate (PCHMA) semi-IPNs containing from 20 to 70 wt% PIB and synthesized without solvent show no cold flow and higher mechanical properties than those of linear PIB or 50 wt% PIB containing blend. In addition, the particular barrier properties toward gas and water are preserved. Those properties arise from the phase co-continuity morphology of the semi-IPN materials which moreover compares with that of corresponding IPNs. A systematic study of the synthesis conditions (nature of the initiator, temperature, cross-linking density) showed that the reacting mixture viscosity is an important parameter that controls the phase separation degree in the final material.
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Polyisobutene polycyclohexyl methacrylate interpenetrating polymer networks
Polymer, 2006Co-Authors: Cedric Vancaeyzeele, Odile Fichet, Sylvie Boileau, Battatchona Amana, Dominique TeyssieAbstract:Abstract Interpenetrating polymer networks (IPNs) combining Polyisobutene (PIB) and poly(cyclohexyl methacrylate) (PCHMA) networks were prepared using an in situ strategy. PIB networks were formed by alcohol–isocyanate addition between the hydroxyl end groups of telechelic dihydroxyPolyisobutene and an isocyanate cross-linker, catalyzed by dibutyltindilaurate (DBTDL). PCHMA networks were obtained from free-radical copolymerization of cyclohexyl methacrylate (CHMA) with ethylene glycol bismethacrylate (EGDM) in the presence of dicyclohexyl peroxydicarbonate (DCPD) as the initiator. The network formations into the IPN architecture were followed by FTIR spectroscopy. In a large composition range, transparent IPNs exhibit two mechanical relaxation temperatures as determined by dynamic mechanical thermal analysis (DMTA), corresponding to those of a PIB enriched phase and of one interpenetrating phase containing the PCHMA network. This morphology was confirmed by IPN surface analysis by AFM. As expected, mechanical properties of PIB networks are improved by the presence of PCHMA network in such IPN architectures.
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Polyisobutene polystyrene interpenetrating polymer networks effects of network formation order and composition on the ipn architecture
Polymer, 2006Co-Authors: Cedric Vancaeyzeele, Odile Fichet, Sylvie Boileau, Judith Laskar, Dominique TeyssieAbstract:Abstract In order to improve Polyisobutene (PIB) mechanical properties, a PIB network is combined with a polystyrene (PS) one into an interpenetrating polymer network (IPN) architecture. PIB network is formed by alcohol addition between the hydroxyl end groups of a telechelic dihydroxy-Polyisobutene and a pluri-isocyanate. PS network is synthesized by free-radical copolymerization of styrene with divinylbenzene. Thus, the optimal synthesis conditions are determined by FTIR spectroscopy and the kinetics of the alcohol–isocyanate addition is studied in detail. A short kinetic study of the PS network formation inside the PIB network is also carried out. The highest degree of interpenetration is obtained by forming the PIB network first. The corresponding transparent IPNs exhibit two mechanical relaxations corresponding to those of PS and PIB enriched phases. However, mechanical properties of PIB networks are tremendously improved by the presence of a PS network in such IPN architectures.
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Polyisobutene poly methylmethacrylate interpenetrating polymer networks synthesis and characterization
Polymer, 2005Co-Authors: Cedric Vancaeyzeele, Odile Fichet, Sylvie Boileau, Dominique TeyssieAbstract:Abstract Interpenetrating polymer networks (IPNs) combining Polyisobutene (PIB) and poly(methyl methacrylate) (PMMA) networks were prepared using a in situ strategy. PIB networks were formed by isocyanate—alcohol addition between the hydroxyl end groups of telechelic dihydroxy-Polyisobutene and an isocyanate cross-linker, catalyzed by dibutyltindilaurate (DBTDL). PMMA networks were obtained from free-radical co-polymerization of methyl methacrylate (MMA) with ethylene glycol bismethacrylate (EGDM) in the presence of dicyclohexyl peroxydicarbonate (DCPD) as the initiator. The synthesis of each network during the IPN formation was followed by FTIR spectroscopy. The highest degree of interpenetration is obtained by forming the PIB network first. The corresponding transparent IPNs exhibit two mechanical relaxation temperatures as determined by Dynamic mechanical thermal analysis (DMTA), corresponding to those of PMMA and PIB enriched phases. Mechanical properties of PIB networks are tremendously improved by the presence of PMMA network in such IPN architecture.
Fritz E. Kühn - One of the best experts on this subject based on the ideXlab platform.
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inorganic organometallic catalysts and initiators involving weakly coordinating anions for isobutene polymerisation
Coordination Chemistry Reviews, 2011Co-Authors: Yang Li, Mirza Cokoja, Fritz E. KühnAbstract:Abstract Polyisobutenes have numerous industrial applications, e.g. as rubbers, sealants, lubricants and oil additives. For the latter two applications, being the largest end-use markets, Polyisobutenes are produced on a several 105 t scale per year. Polyisobutenes applied in mineral oil applications are of low molecular weight. They are industrially produced at temperatures below 0 °C, usually with very active but simple inorganic Lewis acid initiators. During the last decade, research groups developed and examined new types of mostly inorganic/organometallic initiators that work closer to ambient temperatures and provide polymer products of high quality, being at least on a par with the current large scale produced industrial products. An overview on the state of the art and new developments is given in this article.
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solvent ligated copper ii complexes for the homopolymerization of 2 methylpropene
Chemistry: A European Journal, 2008Co-Authors: Lih Ting Voon, Oskar Nuyken, Ahmed K Hijazi, Narayanan Radhakrishnan, Brigitte Voit, Hui Yee Yeong, K Kohler, Fritz E. KühnAbstract:Copper(II) complexes with weakly coordinating counter anions can be utilized as highly efficient catalysts for the synthesis of poly(2-methyl-propene) ("Polyisobutene") with a high content of terminal double bonds. These copper(II) compounds are significantly more active than the manganese(II) complexes described previously, can be applied in chlorine-free solvents such as toluene, are easily accessible, and can be handled at room temperature and in laboratory atmospheres for brief periods, but they are sensitive to excess water, thereby losing their catalytic activity. Replacing the acetonitrile ligands by benzonitrile ligands improves the solubility and catalytic activity in nonpolar and nonchlorinated solvents. However, the benzonitrile copper(II) compounds have lower thermal stability than their acetonitrile congeners.
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molybdenum iii compounds as catalysts for 2 methylpropene polymerization
Angewandte Chemie, 2007Co-Authors: Ahmed K Hijazi, Oskar Nuyken, Eberhardt Herdtweck, Narayanan Radhakrishnan, Kavita R Jain, Hansmichael Walter, Phillip Hanefeld, Brigitte Voit, Fritz E. KühnAbstract:properties, and varied applications. The high-molecularweight (Mn= 300 kgmol ) Polyisobutenes are rubber-like and thus have applications in the rubber goods industry and are used for insulation purposes. Mid-range Polyisobutenes with molecular weights ranging from Mn= 40–120 kgmol 1 are used in glues, sealants, and as chewing-gum base. The lowmolecular-weight Polyisobutenes have weights from Mn= 0.5–5 kgmol 1 and are colorless, honeylike viscous liquids. The so-called highly reactive Polyisobutenes belong to this class of polymers; they have more than 60% terminal (exo) C=C bonds (usually 70–80%) and are of significant commercial interest. After functionalization, these olefins are applied as lubricants or oil additives. 3] It has been known for many years that polymerization of 2-methylpropene (“isobutene”) can be achieved by means of cationic initators like Bronsted or Lewis acids. Typical catalysts are AlCl3, BCl3, or BF3 in combination with water or alcohols as co-initiator. Solvents like methyl chloride, dichloromethane, and n-hexane can be used in a temperature range of 20 8C to 80 8C, depending on the desired molecular weight of the polymeric product. Polymerization under these conditions is fast and exothermic, but it is expensive to maintain the reaction temperatures. Each year, several 100000 t of highly reactive Polyisobutene are produced industrially using these methods. Recently, a new type of catalyst has been described, consisting of solvent-ligated Mn complexes with bulky, noncoordinating counterions. These compounds are applicable for the polymerization of 2-methylpropene. The great advantage of these systems is that polymerization takes place at room temperature or above. We have now found that certain molybdenum(III) compounds significantly surpass the Mn complexes in activity and have other important advantages that are desirable for the preparation of highly reactive Polyisobutenes. Herein, these Mo complexes and their applications in polymerization catalysis are described. The complexes 1–3 are obtained in three steps starting by reaction of Mo2(O2CCH3)4 with a fourfold stoichiometric
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Solvent-ligated manganese (II) complexes for the homopolymerization of isobutene and the copolymerization of isobutene and isoprene
Chemistry - A European Journal, 2004Co-Authors: Mario Vierle, Carmen Haeßner, Martin Bohnenpoll, Ana M. Santos, Klaus Köhler, Oskar Nuyken, Eberhardt Herdtweck, Yanmei Zhang, Fritz E. KühnAbstract:Polyisobutenes with a high content of terminal olefinic groups can be synthesized by using manganese(II) initiators in homogeneous solution. These easily accessible complexes initiate the polymerization at room temperature and above, and afford highly reactive, gel-free Polyisobutenes with high viscosities. Furthermore, the initiators were successfully used for the copolymerization of isobutene with isoprene. The high activities of the Mn(II) initiators seem to be related to their weakly coordinating nitrile ligands, which are easily displaced by substrate molecules. Replacing the nitrile ligands by other more strongly coordinating ligands such as water reduces the initiator activity significantly. The Mn(II) initiators are surprisingly resistant to temperature.