摘要:

AbstractThe kinetics of polymerization of β‐lactones — β‐propiolactone, α‐ethyl‐α‐phenyl‐ and α‐benzyl‐α‐ethyl‐β‐propiolactone — was investigated using nickel carboxylate/phosphine complexes as initiators. The apparent rate constants of initiation and propagation,kiandkp, were calculated assuming first order kinetics. The variations ofkivalues with monomer concentration suggest that the mechanism is more complex, with a reaction order which is not as admitted for calculation. The infrared study has shown that the polymerization initiated by the complex is of zwitterionic type, and the kinetic curves indicate that the nickel carboxyl

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890401

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractPolymerization of 1,4‐(or 1,3‐)divinylbenzene (DVB) in the presence of styrene initiated with lithium diisopropylamide was found to givesolublepoly(DVB‐co‐styrene) having reactive vinyl group as pendant group of the polymer chain. The reactivity of 1,4‐DVB is higher than that of 1,3‐DVB in the copolymerization reaction with styrene as comonomer. It was found also that 1,4‐DVB can be copolymerized with 2‐vinylpyridine to form a soluble copolymer which consists primarily of 2‐vi

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890402

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe cationic transannular oligomerization ofcis‐cis‐1,5‐cyclooctadiene(1), initiated by AlEtCl2and Al2Et3Cl3, was studied. Several cationic catalysts were examined, and the order of activities of these catalysts was found to be the following one: BF3· OEt2

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890403

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractPoly(β‐aminoester)s7 – 12,containing in the repeating unit ethylenebis(carbonyloxy‐1,4‐phenylene)carbonyloxy groups interconnected by polymethylene segments of different length and coupled by diamino spacers, were synthesized from mesomorphic diacrylates and secondary diamines. The thermal behavior and the solution properties of the polymers were investigated. Depending on the structure of the repeating unit, the polymers were found to give rise to either isotropic or anisotropic melts. The incidence and extension of the mesophase are favored in poly(β‐aminoester)s based on even numbered methylene segments and 2‐methylpiperazinediyl spacers. The polymer samples were found to degrade at room temperature, when dissolved in solutions containing water, an organic base or an acid. Based on a macromolecular model compound(14)a degradation process is suggested involving a selective cleavage of the benzoate ester groups assisted by the amino groups

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890404

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA lecithin‐type macromonomer1was synthesized from natural egg phosphatidylcholine (lecithin). The macromonomer has an olefinic polymerizable group at the hydrophilic site, and is characterized by its chemical structure resembling lecithin. It could be polymerized in a liposome system by UV irradiation, giving polymers with a maximum molecular weight of 98 000. Polymers with molecular weights above 48 000 form thin and flexible membranes with a few 10 μm in thickness. The polymers can also be redispersed in water and the liposomes can be reconstitut

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890405

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA thin film (thickness: 200 nm) of metal‐free polyphthalocyanine, which is insoluble in organic solvents, was prepared by an evaporation‐polymerization process under mild conditions developed by us. The thin film is not only though, but it also resists chemicals and heat. Its conductivity is 1,1 · 10−4S · cm−1, and it increases to 0,15 S · cm−

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890406

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

Abstract1‐(4‐Acetoxy)‐3‐(2H‐benzotriazolylphenyl)vinyl acetate(4)was synthesized. The polymerization of4afforded polymer5with a relatively low molecular weight (= 2000). Copolymerizations of4(3,7 wt.‐%) were carried out with styrene and methyl methacrylate to copolymers6and7,respectively. Polymer5and copolymers6and7were characterized by1H and13C NMR and by IR and UV spectroscopy. Their UV spectra show a strong absorption in the near UV spectrum.4may thus be considered as a potential comonomer for UV

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890407

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractPolyurethanes with azobenzene side groups attached via an alkyl spacer of different length were synthesized fromN‐[4‐phenylazophenyl]‐ω‐[bis(2‐hydroxyethyl)amino]alkanamides (5) and equimolar amounts of diisocyanates such as hexamethylene diisocyanate (HDI), 4,4′‐methylenedicyclohexyl diisocyanate, 1,3‐cyclohexylenedimethyl diisocyanate, 2,4‐toluylene diisocyanate, and 4,4′‐methylenediphenyl diisocyanate. Polyurethanes obtained from diols5with HDI have a mesomorphic phase as determined by DSC and polarizing microscopy and are crystalline at room temperature as evid

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890408

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe preparation of aromatic macromonomers with hydroxyl functions was achieved by termination of living polystyrene (PSLi) upon addition of 2,5‐dimethoxybenzyl bromide(2)or 1,1‐bis(4‐methoxyphenyl)ethylene(16). Ether cleavage with boron tribromide resulted in the formation of the de‐protected macromonomers15and17. Side reactions occurring in the functionalisation reaction with2were investigated by means of a respective model reaction. The formation of side products could be suppressed by reacting PSLi with 1,1‐diphenylethylene prior to functionalisation with2. The macromonomers were characterized by GPC, UV, and FT‐IR s

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890409

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractCrosslinkable and crosslinked liquid‐crystalline polymers with elastic properties were prepared from main‐chain and combined main‐chain/side‐group polymers. These polymers exhibit nematic, smectic A, and smectic C phases. Polymers of these types with azoxybenzene as mesogen do not crystallize upon cooling. As a consequence, the liquid‐crystalline phases are frozen in glassy around room te

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890410

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY