摘要:

AbstractSelective graft copolymerizations onto different segments of a poly(ether‐urethane) (PEU) by using two different methods, i.e. ceric salt initiation and controlled oxidation, were investigated. By ceric salt initiation the grafting takes place mainly at the hard segment, while the controlled oxidation gives grafted hydrogels at the soft segment. The effects of different factors on graft copolymerization in both methods including ceric salt concentration, monomer concentration, PEU composition and oxidation time were investigated. Another kind of multiphase block copolymers, a poly(ether‐ester), also can be graft‐copolymerized by both me

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860801

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractPhotochemical and radical polymerization of 2‐methylene‐4‐phenyl‐1,3‐dioxolane (1) were carried out leading to the same polyester2. By radical copolymerization of1with methyl methacrylate using various mole ratios of the monomers, the corresponding copolymers with various contents of ester groups in the backbone were

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860802

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractPolyvinyl chloride (PVC) was degraded at processing temperatures in an inert atmosphere. The samples were analyzed by means of a size exclusion chromatograph equipped with a differential refractometer and a photo‐diode array UV‐visible detector. This enabled us to record online the presence of polyenes at different positions along the molecular weight distribution of the degraded polymer. Polyenes proved to be concentrated on the low molecular weight side of the distribution and, more specifically, on the high molecular weight side, which had been broadened upon degradation. The results indicate that low molecular weight PVC degrades relatively fast and that PVC molecules containing polyenes crosslink eas

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860803

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractRates of photochemical reactions of polymers containing pendant cinnamic ester moieties and photosensitizing 4‐nitrophenoxy or 4‐nitro‐1‐naphthyloxy groups were determined in dilute benzene and tetrahydrofuran solutions. The rate of photodimerization of the polymers obeys first order kinetics in diluted solution and is affected by the type and content of pendant photosensitizing groups and by the structure of the polymer skeleton. By comparison of the rate of photodimerization of three homopolymers and six copolymers, it could be concluded that the polymers consisting of flexible segments have a higher rate of photodimerization than those made of rigid s

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860804

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe influence of different substituents (nitro and methoxy groups) on the physical properties — fusibility and solubility — and the electrical conductivity of alkoxylated poly(1,4‐phenylenevinylene‐1,4‐phenylenevinylene)s (9, 10, 12and13) and of the corresponding model compounds (15, 16, 18and19), were studied. The conductivity at room temperature, σ298K, was found to be generally increased for polymers with nitro substituents by 2–3 orders of magnitude and for dimethoxy substituted polymers up to 4 orders of magnitude, as compared with the unsubstituted polyvinylenes. Iodine doped polyvinylenes show as an average d. c. electrical conductivities 2 orders of magnitude higher than those of the origi

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860805

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractSeveral series of thermotropic liquid‐crystalline polyesters, based on 4‐chlorocarbonyl phenyl esters of aromatic dicarboxylic acids (1–4) and phenols or aliphatic diols, were synthesized and studied by polarizing microscopy and differential scanning calorimetry (DSC). A relationship between geometry of mesogenic moiety and stability of mesophase formed by the polymers was established. The effect of both the length and chemical structure of the flexible fragments on the mesomorphic properties was revealed for polyesters obtained from aliphatic diols. Several polymers were obtained whose temperatures of transition into the liquid crystalline state were found to be below 100°C. Two series of low‐molecular‐weight liquid‐crystalline compounds were synthesized to compare their properties with those of the polymers of similar structure. Most of the low‐molecular‐weight analogs have not been described so far. They predominantly form a smecti

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860806

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractPhotopolymerization of methyl methacrylate (MMA) in bulk and in solution was studied using the combination benzil (BZL)/triethylamine (TEA) as photoinitiator. The initiation was found to occur through photoreduction of the ketone in presence of an amine via exciplex formation. A kinetic study of the polymerization showed that both carbonyl groups of benzil are involved in exciplex interaction, resulting in diradical formation. An analysis of the initiator dependent termination process revealed that primary radical termination is predominant in the particular system compared to the degradative initiator transfer. A kinetic scheme was designed to account for the various wastage reactions occurring in the polymerization system.

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860807

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe radical copolymerization of 1‐acryloyl‐ and 1‐methacryloyl‐3‐methylpyrazole (1aand1b) with acrylic acid or methacrylic acid in solution was studied. Copolymers containing carboxyl as well as 3‐methyl‐1‐pyrazolylcarbonyl groups as side chains were prepared via the reaction of 3(5)‐methylpyrazole with activated poly(acrylic acid)s of various molecular weights. The hydrolysis data suggest that the release rates of the biocide 3(5)‐methylpyrazole from the investigated copolymers vary significantly depending on the content of carboxyl groups and their change du

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860808

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe homogeneous system resulting from the reaction between tetrabenzylzirconium and triethylaluminium is an active catalyst for the polymerization of styrene, andp‐methyl‐, α‐methyl andp‐chlorostyrenes. The molecular weights and the structures of the resulting polymers are highly dependent on the nature of the monomer and on the reaction medium. In toluene, styrene andp‐methylstyrene give essentially linear unsaturated dimers, whereasp‐chlorostyrene leads to a polymer with a high molecular weight. In methylene dichloride higher oligomers and a polymer are obtained simultaneously from all the monomers. The comparative behaviour of the styrene derivatives was examined in copolymerization experiments under various experimental conditions. The ratios of monomer incorporation were compared with those reported in the literature for related systems. The results show that, according to the monomer and the reacting medium, the same catalytic system is able to induce polymerizations of the “coordinated anionic”, radical a

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860809

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractA new flexible and crosslinkable copolyimide was prepared by low temperature polycondensation between bis [4‐(4‐chloroformylphthalimido)phenyl] ether (1), bis(4‐aminophenyl) ether and liquid α,ω‐bis[2‐(4‐piperazinyl)ethylaminocarbonyl]poly(butadiene‐co‐acrylonitrile) in DMAc solution. The polymer is soluble in DMF, DMAc, NMP,m‐cresol, DMSO and concentrated sulfuric acid. On heating with or without dicumyl peroxide the poly

ISSN:0025-116X    

DOI:10.1002/macp.1985.021860810

出版商:Hüthig&Wepf Verlag    

年代:1985

数据来源: WILEY