摘要:

AbstractThe radical terpolymerization of sulfur dioxide and methyl acrylate with 1,3‐butadiene, 2‐methylpropene, propene, 1‐hexene, 1‐octene and vinyl chloride was studied by comparing the composition of terpolymers obtained under different reaction conditions and by analysis of13C NMR spectra of selected terpolymers and copolymers. In the majority of systems studied, products are formed in which the ratio of SO2monomeric units to vinyl monomeric units is near to unity. The content of methyl acrylate monomeric units can change over a very wide range and depends mainly on the electron‐donor properties of the vinyl monomer used, feed composition and conversion. An increase of the methyl acrylate content is also observed in many systems with a rise of the reaction temperature. The results obtained are interpreted in terms of a mechanisms involving the addition of individual monomers and reversibility of steps in which carbon‐sulfur bonds

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900401

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractEthyl 1‐substituted 2‐vinylcyclopropanecarboxylate derivatives (VCPs) were prepared from butadiene and the corresponding substituted diazoacetate in the presence of rhodium diacetate as a catalyst. The polymerization behavior of the obtained monomers was investigated revealing that VCPs undergo radical ring‐opening polymerization to form poly(1‐alkyl‐1‐ethoxycarbonyl‐3‐pentenylene)s and that there is a marked influence of the 1‐substituent of VCPs on the polymerization rate. The reaction of VCPs with thiophenol was also carried out as a model reaction of the

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900402

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe synthesis oftert‐butoxycarbonyl‐ and benzyloxycarbonyl‐modified monomers was performed by the addition ofp‐chlorophenyl isocyanate or benzyl isocyanate to the free OH groups ofN‐(2‐hydroxy‐2‐methylpropyl)methacrylamide (1),N‐(2‐hydroxy‐2‐methylpropyl)‐6‐methacrylamidohexanamide (2) andN‐β‐hydroxyphenethylmethacrylamide (3). The monomers were homopolymerized and copolymerized with MMA. The kinetics of acidic‐induced amine cleavage from the new amino‐protecting groups was followed by NMR spectroscopy and it became evident that the polymers are suitable amino‐protecting groups. Ca2+ions enhance the rate of amine cleavage considerably. Neighboring group effects, the influence of comonomers and spacer groups on the reactivity of

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900403

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe new catalytic system comprising a diester as an internal Lewis base and a silane (triethoxyphenylsilane) as an external Lewis base presents important differences to the classical third generation catalyst with two esters in the system, i. e. a high isotacticity is obtained with a low ratio Al/Lewis base, the stereospecificity is stable with temperature and time, the sensitivity to hydrogen concerning the average molecular weight is high and the activity, which remains low without hydrogen, is greatly enhanced by the transfer agent. The selectivity of the system is controlled in a complex manner by the concentration and ratio of the cocatalytic system.

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900404

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractAs in the case of the third generation MgCl2‐supported stereospecific catalysts, characterized by the use of aromatic esters as internal and external Lewis bases, the new improved family of catalysts, containing an aromatic diester as internal Lewis base and a trialkoxyphenylsilane as external Lewis base, was found to be sensitive to hydrogen. A very strong activation effect, followed by deactivation, was observed upon introduction of small amounts of hydrogen. In the present case the effect is reversible, unless rather high hydrogen pressure (2 bar) is used. The activation effect was observed with any of the cocatalysts and even in the absence of an external Lewis base. The effect is reduced or even suppressed if enough ethylene is used in the copolymerization with propene. Owing to the competition between ethylene and hydrogen for the activation, it is assumed that the step sensitive to hydrogen is that of initiation rather than propagatio

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900405

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractMicrolatices of acrylic monomers, in the particle size range of 10–30 nm, were prepared by photopolymerization of micellar systems (monomer‐surfactant) and of microemulsions based on monomer‐surfactant‐cosurfactant. Formation of monomer containing microemulsions is shown for various surfactants in combination with alcohols as cosurfactants and the corresponding phase diagrams are given. Photopolymerization, in the presence of oil‐soluble initiators, was investigated for such systems based on cyclohexyl methacrylate (CHMA) and on tetramethylene dimethacrylate (BDMA). Crosslinked and non‐crosslinked colloidal polymer particles could be obtained, with a 5–10% solid content of polymer. The variation of particle size, and the molecular weight for non‐crosslinked systems, was studies as a function of initiator concentration, and monomer/surfactant ratio. The smallest particles (10–15 nm) are obtained for the system BDMA/la

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900406

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractA novel class of carbanionic dopant systems was developed which facilitates the intercalation of tetraalkylammonium ions into polyacetylene (PA), which was considered impossible by chemical methods so far. The chemistry of the dopant system was discussed. The presence of [R4N]+ions in PA was verified by elemental analysis and IR spectroscopy. The maximum doping levels were determined in the case of several carbanionic systems and also by systematically varying the size of the [R4N]+ions. A correlation between maximum doping levels and the redox‐potentials of the carbanions was establishe

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900407

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe reaction of a living poly(tetrahydrofuran) (poly(THF)), prepared with methyl trifluoromethanesulfonate as an initiator, with 3‐sodiopropoxydimethylvinylsilane was carried out to produce a uniform poly(THF) macromonomer with a vinylsilane end‐group. Poly(vinyl acetate)‐graft‐poly(THF) of controlled graft segment length was then synthesized through radical copolymerization of this poly(THF) macromonomer with vinyl acetate. The subsequent saponification with NaOH in methanol provided poly(vinyl alcohol)‐graft

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900408

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe kinetics of the 2,2′‐azoisobutyronitrile (AIBN)‐initiated emulsion polymerization of methyl methacrylate and butyl methacrylate was studied in the presence or in the absence of 4‐stearoyloxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl radical (STMPO) situated in the oil (monomer) phase. The polymerization was initiated and oligomeric radicals were formed in the aqueous phase to which methyl methacrylate (butyl methacrylate) and AIBN were transferred. Polymerization does not take place in the oil phase because of the inhibitor present. Relatively short inhibition periods of polymerization observed in systems containing STMPO confirm that a small part of STMPO was transferred from the oil to the water phase. The length of the inhibition period in the emulsion polymerization is determined by a competition between the addition reaction of primary radicals with monomer and the termination reaction of primary radicals with STMPO as well as by the rate of STMPO scavenging by oligomer‐monomer and polymer‐monomer particles. The polymerization system studied belongs to a group of partitioned polymerization systems characterized by simultaneous transfer of monomer and initiator from the oil to the water phase, where the initiation of polymer

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900409

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe partitioned emulsion polymerization of methyl methacrylate and acrylonitrile initiated by ammonium peroxodisulfate and/or 2,2′‐azoisobutyronitrile was studied in the presence ofp‐benzoquinone, 2,2‐diphenyl‐1‐picrylhydrazyl, 4‐hydroxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl, 4‐benzoyloxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl, 4‐methacryloyloxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl, 4‐acetoxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl and 4‐stearoyloxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl radicals. These compounds with the exception of 4‐stearoyloxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl inhibit the partitioned emulsion polymerization of methyl methacrylate. In the partitioned emulsion polymerization of acrylonitrile 4‐stearoyloxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl was also found to be effective. This fact was ascribed to the increased water solubilit

ISSN:0025-116X    

DOI:10.1002/macp.1989.021900410

出版商:Hüthig&Wepf Verlag    

年代:1989

数据来源: WILEY