摘要:

AbstractTriblock copolymers of different alkyl methacrylates with side chains containing 1 to 12 carbon atoms were synthesized by anionic polymerization in tetrahydrofuran with diphenylmethyl sodium or naphthalene sodium (sodium dihydronaphthylide) as initiators. The polymer samples were fractionated by means of solvent/non‐solvent systems. Gel permeation chromatography (GPC), light scattering, osmometry, and elemental analysis were used to characterize the fractions. The copolymers were found to be free of homopolymers and the polydispersity of molecular weight of the fractions to be very lo

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780111

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe free radical polymerization of methacrylic anhydride in chloroform solutions was investigated at different temperatures. By employing statistical analysis of the experimental data, it could be shown that in all the cases the dependence of the mole fraction of cyclic structural units on the monomer concentration, at which the polymer has been obtained, is in agreement with a kinetic relationship generally valid for the free radical cyclopolymerization of symmetrical unconjugated dienes.

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780112

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe temperature dependence of the cyclization ratio of the free radical cyclopolymerization of methacrylic anhydride in chloroform solutions was investigated. The experimental difference between the activation entropy of the intramolecular cyclization and the activation entropy of the intermolecular addition of the growing chain radical onto a monomer molecule was found to agree satisfactorily with the difference calculated on the basis of a semiempirical method. It came out that, even in the present case, the intramolecular cyclizations are favoured over the intermolecular additions by a smaller entropy decrease.

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780113

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractRate and equilibrium constants (kfandK, respectively) for the addition of cyanideion to poly[1‐(4‐vinylbenzyl)nicotinamide chloride] (poly{1‐[4‐(3‐aminocarbonylpyridiniomethyl)phenyl]ethylene chloride}) (poly(1)) and a corresponding monomeric derivative of nicotinamide, 3‐aminocarbonyl‐1‐benzylpyridinium chloride (2), were evaluated at 30°C, in an aqueous system. The rate constant for the reaction of poly(1) with CN−at μ = 0,1 mol 1−1was found to be higher by a factor of 22 and the association constant by a factor of about 65, compared with those for the reaction of2with CN−. At a lower ionic strength (μ = 0,008 mol 1−1), the reaction parameters were markedly enhanced (108‐fold and 218‐fold, respectively). The rate enhancements in the polymeric system are attributable to the increase in the ΔS ≠fterm. This favorable entropy term caused the deviation from the linear logK‐logKfrelationship which h

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780114

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractRate and association constants (k f, SO 2−3andK SO 2−3) for the addition of sulfite ions to five nicotinamides substituted at the ring nitrogen, (2a–e), and to poly(1‐(4‐vinylbenzyl)nicotinamide chloride) (poly{1‐[4‐(3‐aminocarbonylpyridiniomethyl)phenyl]ethylene chloride}) (poly(1)) were determined at 30°C in aqueous systems. It was found that the reaction parameters for the addition of SO 2−3to poly(1) are markedly enhanced (20500‐fold in thek f, SO 2−3term and 510‐fold in theK SO 2−3term) compared with the addition to the corresponding monomeric compound, 3‐aminocarbonyl‐1‐benzylpyridinium chloride (2d), and the enhancements are suppressed with increased ionic strengths. These enhanced reaction parameters for poly(1) are deviated to the upper area by two logarithmic units from a linear logK SO 2−3vs. logk f, SO 2−3relationship which holds for monomeric nicotinamides. This means that the rate constant is enhanced more effectively that the association constant in the polymeric system. Plots of logKCN−vs. logK f, SO 2−3and of logkf, CN‐ vs. logk f, SO 2−3‐ gave good linear relationships. The plot for poly(1), greatly deviated again to the upper area. The SO 2−3i

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780115

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe copolymerizations of acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, methyl vinyl ketone, acroleine, and acrylic acid with butadiene were carried out in the presence of the Lewis acids ZnCl2, BF3, CH3AlCl2, C2H5AlCl2, AlCl3, SnCl4, and TiCl4and also in the absence of catalyst. Relative reactivity orders of the above polar vinyl monomers in the copolymerization and 1,4‐cycloaddition reactions with butadiene and also the catalytic activity orders of Lewis acids in these reactions were determined. The composition of the polymers formed and the structure of their butadiene units were also determined. The mechanism of the copolymerization and 1,4‐cycloaddition of the polar vinyl monomers with butadiene in the presence of Lewis acids is discus

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780116

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe solution polymerization of styrene in methylene dichloride catalysed by trifluoromethanesulfonic acid takes place at a high rate even at low catalyst concentration. The S‐shaped course of the conversion curves is explained by a reaction mechanism, in which the catalyst rapidly forms an inactive complex with one monomer molecule, and this monomer‐acid complex is in equilibrium with the free catalyst molecule from which the propagating species are formed. Therefore, the formation of active initiating species becomes a slow process which depends also on the change of monomer concentration during polymerization. It is assumed that the active initiating species are formed from two or three molecules of acid and this process is supposed to be a determining step in the mechanism of the styrene polymerization.The conductivity of the polymerizing system is caused probably by at least two species: firstly by the 1‐aralkyl‐3‐phenylindanyl cation which was found by means of UV spectroscopy and which is formed during and after the polymerization as product of termination reaction; secondly by another species, which takes part, as we assume, in the propagating process, probably as polystyryl c

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780117

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe electrochemical homopolymerization of maleic anhydride was investigated at constant electric current in a divided cell. The polymer yield depended markedly on the quantity of current passed through the solution, polymerization time, and on the nature of supporting electrolytes and solvents. The visible spectra of electrolysed solutions and the IR spectra of poly(maleic anhydride) were measured. The polarographic measurements revealed thatN‐methylpyridinium iodide, employed as supporting electrolyte for the polymerization of maleic anhydride, was reduced at a smaller cathodic voltage than maleic anhydride. Under the given reaction conditions the electrolytic reduction products of the salt might have initiated the polymerization. An anionic polymerization mechanism is assume

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780118

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractUV‐Irradiation of phenyl‐substituted poly‐p‐xylylidenes induces photoconductivity in the range of 7000–17000 cm−1. The spectral distribution is identical with that of photoconductivity found in macromolecular radical cations produced chemically by oxidation with antimony pentachloride. This supports the assumption that the induced photoconductivity can be attributed to the photochemical generation (UV) and the optical excitation (VIS/NIR) of macromolecular r

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780119

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe paper contains the IR‐spectra of the coordination compounds of the poly(2‐,3‐, and 4‐vinylpyridine)s with the chlorides of Ru, Pd, and Rh. The shifts of the fundamental vibrations of the pyridine ring are discussed, and the spectra are analysed. In comparison with low molecular weight analogues, the spectra are simpler, and the vibration bands are wider, which is due to the polymeric character of the

ISSN:0025-116X    

DOI:10.1002/macp.1977.021780120

出版商:Hüthig&Wepf Verlag    

年代:1977

数据来源: WILEY