摘要:

AbstractThe 100 MHz spectra of polymers of propene sulfide and propene‐2‐d1sulfide have been determined in CDCl3, CCl4, and C6D6. In the deuterated polymer the main‐chain protons give rise to two overlapping AB quartets in which the two pairs of upfield B lines are coincident and the two pairs of downfield A lines are resolved. With CdCO3as polymerization catalyst the downfield quartet is twice as strong as the upfield quartet. The former is ascribed to an isotactic dyad:and the latter to a syndiotactic dyad:Other catalysts (ZnCO3, CuCO3, SiO2/Al2O3, Na) produce an essentially atactic structure. The values τA= 7.125, τA′ = 7.155, τB= 7.45,JAB= −12.9 Hz, derived from the spectrum of the deuterated polymer (in CCl4) were used to obtain the following values from the spectrum of the undeuterated polymer (tertiary proton =Hc): τC= 7.131,JBC= 10.0 Hz,JCA= 4.1 Hz. The magnitudes of the vicinal coupling constants indicate a preferredtransconformation for the mainchain CC bond. τA, τB, and τCare somewhat dependent on solvent; τCH3= 8.63, independent of solvent,

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090101

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractThe copolymerization of carbonyl sulfide with aziridines such as ethylenimine, propylenimine, andN‐ethylethylenimine was studied in various organic solvents. The copolymerizations occurred easily without the addition of any catalyst and gave white powdery crystalline copolymers. The copolymers produced were insoluble in many organic solvents, but soluble inp‐chlorophenol and dimethyl sulfoxide. The elementary analyses and the infrared spectra showed that alternating copolymers which have a thiourethane structure were produced. In the copolymerization of carbonyl sulfide with ethylenimine, both the polymer yield and the molecular weight of the resulting polymer increased with the use of a solvent having a higher dielectric constant, and also with an increase in the ratio of carbonyl sulfide to imine in the feed. The rate of copolymerization of carbonyl sulfide with aziridines was in the order of ethylenimine>propylenimine>andN‐ethylethylenimine. Irradiation of the copolymers improved their thermal properties and increased their melting

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090102

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractPeculiarities in the process of the mechanochemical grafting of polystyrene on freshly formed surface of particles of calcium carbonate on grinding in styrene were studied. It was established that the formation of homopolymer in this process is the result of rupture of individual chains of macromolecules, which are bound to the surface. If a small quantity of water is present in the monomer, the grafting is enhanced, due to an increase of the specific surface of the powder as a result of the reduction of its durability due to adsorption (Rehbinder effect). The grafting of polystyrene makes the solid surface hydrophobic and increases the activity of calcium carbonate as a filler for rubber.

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090103

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractHomopolymerization and copolymerization of trioxane by use of various catalysts have been investigated. When MoO2(AcAc)2is employed, crystalline homopolymers and copolymers as formed from polymerization exhibit significantly higher melting points than corresponding polymers prepared by use of ordinary cationic catalysts. The higher melting points are attributed to different morphology of the polymer chains formed during polymerization. We now call this phenomenon morphospecific polymerization. This communication describes our results in the copolymerization of trioxane and 1,3‐dioxolane and some outstanding properties of the copolymers. A polymerization mechanism is also propose

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090104

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractThe preparation and properties of a unique new class of polymers containing polyhedral borane cages as part of the backbone polymer chain are described. The synthesis of polyamides, polyesters, polyureas, and polyurethanes proceeds from suitably chosen B10and B12polyhedral borane dicarbonyls, diols, and diisocyanates by typical condensation polymer techniques. Each complementary monomer may be a borane compound, but more often higher molecular weight products are provided when one monomer is a conventional organic reagent such as an aromatic diisocyanate. The polyamides prepared from 1, 12‐B12H10(CO)2and organic diamines were crystalline and soluble, but molecular weight were limited because the amidation reaction was reversible and/or the amide linkage could be split by nucleophilic attack by some solvents. The polyurethanes prepared from Na2B12H10(OH)2and aromatic diisocyanates were high molecular weight and relatively more stable. Clear, colorless, tough films were prepared. These polymers were soluble in many polar solvents and exhibited typical polyelectrolyte behavio

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090105

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractThe influence of free, diffusion‐control quenchers of triplets (naphthalene, biphenyl, 2,5‐dimethyl‐2,4‐hexadiene) on the photolysis of poly(vinyl phenyl ketone) in benzene solution has been investigated. The Stern‐Volmer plots for quenching of main‐chain scission were linear, and the quenching constants were independent of the macroviscosity of the solutions. Copolymers of vinyl phenyl ketone with 1‐vinylnaphthalene and 2‐vinylnaphthalene containing as much as 10% (by weight) vinylnaphthalene were prepared. The photolysis of the copolymers was compared with the photolysis of poly(vinyl phenyl ketone) in the presence of free naphthalene. It was found that the quenching efficiency of found naphthalene units was about 21 times higher. The possibility of migration of the absorbed energy along the polymer chain is discussed. The relation between average‐number molecular weightMnand intrinsic viscosity [η] has been determined osmometrically. For unfractionated poly(vinyl phenyl ketone) in benzene at 30°C, the relation [η]= 2.82 × 10

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090106

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractThe rate of polymerization of vinyl acetate in systems containing poly(vinyl acetate) seed particles was investigated. A significant reduction in rate was observed when nonionic surfactants were adsorbed onto the particles prior to polymerization. The molecular weight of the poly(ethylene oxide) moieties in the surfactants was varied over two decades. The diminution in rate was relatively insensitive to this molecular weight variation, at least for higher molecular weights (≥20,000). A minimum in the rate was apparent at lower molecular weights. No new nucleation was detectable in any of these systems. The results have been interpreted in terms of two properties of the dissolved poly(ethylene oxide) layers through which the oligomeric free radicals must diffuse in order to reach the major loci of polymerization inside the particles. These two properties, the effective thickness of the dissolved poly(ethylene oxide) layer and its average microscopic viscosity, are expected theoretically to be approximately self‐compensating when the molecular weight is var

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090107

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractThis paper discusses monomer reactivity ratios in various radiation‐ and redox‐initiated graft copolymerizations. The polymers studied were polyethylene, cellulose acetate, poly(vinyl chloride), polytetrafluoroethylene, poly(vinyl alcohol), and poly(methyl methacrylate); the comonomer mixtures were styrene–acrylonitrile, methyl acrylate–styrene, acrylonitrile–methyl acrylate, and vinyl acetate–acrylonitrile. The polymer–comonomer mixture systems were so chosen as to permit study of both homogeneous and heterogeneous systems. The homogeneous systems included systems of low and high viscosity. The heterogeneous systems included both polymers swollen by the comonomer mixture and polymers not swollen by the comonomer mixture. None of the homogeneous grafting systems studied showed deviations from the normal copolymerization behavior under a variety of experimental conditions. Monomer reactivity ratios in graft copolymerization were the same as the values in nongraft copolymerization. The heterogeneous systems in which the polymer was swollen by the comonomer mixture yielded grafted copolymer compositions which were the same as those in nongraft copolymerization. The heterogeneous grafting system polytetrafluoroethylene/styrene–acrylonitrile showed deviations from normal copolymerization behavior at low degrees of grafting when the reaction was only on the polymer surface. The behavior became normal at higher degrees of grafting when the system approaches that in which the polymer is swollen by the comonomers. In all reaction systems, it was found that the use of radiation to initiate the reaction does not in any way affect the copolymerization behavior of the two monomers in a

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090108

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractAnionic copolymerization of β‐cyanopropionaldehyde (M1) with methyl isocyanate (MeI, M2) was studied with use of benzophenone–dilithium complex as initiator at −78°C. The values of monomer reactivity ratio were determined to ber1= 8.3 ± 0.3 andr2= 0.01 ± 0.01. The structure of resulting copolymer was investigated by means of NMR analysis. The MeI unit is presumed to enter the copolymer chain through its C

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090109

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractThe cationic electropolymerization of isobutyl vinyl ether was induced and controlled by sequences of pulses of current of various lengths and of similar or opposite polarity. A remarkable degree of control over the rate of the reaction was demonstrated for a system that is subject to “flash” polymerization by conventional chemical initiators. The mechanism is shown definitively not to correspond to the electric field effects proposed by Tanaka, Ise and Sakurada as applicable to all such electropolymerizati

ISSN:0449-296X    

DOI:10.1002/pol.1971.150090110

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY