摘要:

AbstractThe polymerization of isobutylene–butadiene monomer mixtures by a cobalt‐containing catalytic system (cobaltous acetylacetonate–diethylaluminum chloride–water) yields a homopolymer mixture consisting of polyisobutylene and polybutadiene. It is assumed that the polymerization of both monomers proceeds according essentially identical reaction mechanisms, i.e., isobutylene polymerizes cationically and butadiene follows a coordination‐cationic

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091201

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractThe radiation‐induced copolymerization of chlorotrifluoroethylene with ethyl vinyl ether was investigated in the liquid phase at 20 and −78°C over a wide range of monomer compositions. A copolymer was obtained in which the monomers alternate with regularity along the polymer chain over the entire range of monomer compositions investigated. Both the rate of copolymerization and the intrinsic viscosity of the resulting copolymer were found to depend strongly on the initial monomer composition, both reaching a maximum value at an equimolar concentration of the monomers. The monomer reactivity ratios were determined and correspond well with calculated values. A decrease in the irradiation temperature was accompanied by a marked decrease in the rate of copolymerization and the intrinsic viscosity of the copol

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091202

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractAnionic living polymerization of α‐methylstyrene containing a small amount of THF (less than 10%) was studied at temperatures between −30°C and 50°C. At any temperature studied, a certain quantity of monomer remained without further polymerization. The effect of temperature and THF content on the final state was completely different in low and high temperature regions; at temperatures lower than ca. 20°C, the final monomer concentration decreased with increasing polymerization temperature and THF content. This is explained by the concept of “stopping of polymerization due to vitrification” of the polymerizing mixture. In fact, the final reaction mixture is really glassy in most cases and the red color of living polymer buried in the glass is discolored only very slowly when exposed to air. Detailed analysis of the results showed that the vitrification stopping holds only approximately. At temperatures higher than ca. 30°C, a normal equilibrium between propagation and depropagation holds, and the final monomer concentration increased with temperature. It is, however, far less than the equilibrium monomer concentration obtained in solution polymerization at the same temperature, and it increased appreciably with the increase in THF content. It is shown that the behavior of the equilibrium for the whole concentration range can be explained satisfactorily by a thermodynamic theory of ter

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091203

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractSome representative examples of a new family of aminimide monomers, i.e., trialkylamineN‐acryloyl orN‐methacryloyl glycinimides and β‐aminopropanimides have been prepared and studied. These are the first examples of a possible large family of primary aminimide monomers. With radical initiators, the acryloyl and monosubstituted methacryloyl monomers readily homopolymerize. The disubstituted methacryloyl aminimides do not homopolymerize under the same conditions. All of the new monomers copolymerize with styrene, methyl methacrylate, andn‐butyl acrylate. The various polymers were characterized by IR, DTA, TGA, GPC and inherent viscosities. When heated (160°C) the polymers liberate amine and crosslink in the presence of active hydrogen moieties to give resins with carbamate, urea, allophonate, etc., residues. When no active hydrogens are available during heating, polymers can be prepared with pendent primary isocyanate groups. This preliminary work shows these monomers to be highly useful for preparing a wide variety of reactive c

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091204

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractPoly(vinylidene chloride) precipitates as a crystalline phase during the polymerization reaction. Under the conditions studied, this phase is made up of complex particles with a lamellar substructure. The detailed morphology is very sensitive to reaction medium. The morphology developed by particles formed during polymerization of vinylidene chloride in dioxane suggests a mechanism of polymerization followed by crystallization. The morphology observed in mass polymerization suggests that both processes occurs simultaneously. Kinetic data, however, suggest a solid‐phase reaction mechanism for both cases. The results are analyzed by comparison with a model that takes into account the solid‐phase morphology. The theoretical analysis is consistent with experimental results if it is assumed that polymerization occurs on the edges of the lamellar cryst

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091205

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractLow‐angle x‐ray scattering methods have been used to evaluate some parameters like specific inner surface of the dispersed phase, transverse lengths, the length of in homogeneity, the length of coherence, and the air‐fraction of the scattering particles in Elastoidin. The low‐angle Kratky camera of the latest design was used for the experimental measurements. Since the sample under investigation is a densely packed solid polymer, the theories of Kratky and Kratky and Porod have been used to evaluate these par

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091206

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractEnthalpy, entropy, and Gibbs free energy of epichlorhydrin, bisphenol A, and epoxy resins from specific heat data obtained experimentally in a DuPont 900 differential thermal analyzer are described. The epoxy resin used has a second‐order transition temperature around −15°C and a chain rigidity of 50.6 c

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091207

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractWater‐soluble cobalt(III) chelates having a polymeric ligand such ascis‐[Co(en)2‐PVPCl]Cl2andcis‐[Co‐(trien)PVPCl]Cl2(PVP = poly‐4‐vinylpyridine) were prepared by substitution reactions between cobalt(III) chelate and PVP in water–alcohol solution. PVP of different degrees of polymerization was used as the ligand in preparation of these complexes. The PVP complexes were identified and their properties ascertained by microanalysis and by a study of the infrared, ultraviolet, visible, and PMR spectra. Most of the characteristic properties of these complexes may be ascribed to the polymeric structure of

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091208

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

AbstractWater‐soluble Co(III)–PVP complexes (where PVP = poly‐4‐vinylpyridine) were prepared, and the specific rates and activation parameters for the iron(II) reductions ofcis‐Co(en)2XCl2+(where X = PVP or pyridine and en = ethylenediamine) were determined in dilute sulfuric acid solutions. Under the conditions [H2SO4] = 0.50M, Σ[SO42−] = 1.25Mat 25°C, the second‐order rate constants and activation entropies, respectively, for thecis‐Co(en)2−XCl2+are (4.10 ± 0.05) × 10−3l./mole‐sec and −14 ± 0.6 eu for × = pyridine, (2.1 ± 0.1) × 10−3l./mole‐sec and −6.0 ± 1 eu for × = PVP (Pn= 19), and (2.42 ± 0.08) × 10−3l./mole‐sec and −2.5 ± 0.8 eu for × = PVP (Pn= 98), wherePnis the degree of polymerization of the PVP. The main feature of the polymer effect in the electron‐transfer reactions of the PVP complexes in which uncoordinated pyridine rings are present may be attributed to greater activation entropy. Such a greater entropy for the PVP complex may be partly ascribed to the in

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091209

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY

摘要:

Abstract(+)‐1,2‐Diethoxypropane, a model diether for the repeating unit of poly(propylene oxide), was prepared, and its behavior in solutions regarding optical rotatory dispersion and proton magnetic resonance was compared with those of the polymer. It was found that the model compound and the poly(propylene oxide) show essentially the same optical properties in solutions. By using the Brewster model of optical activity, it was concluded that the solvation of the polymer may well modify the polarizability of the optically active species to cause changes in the order of the polarizabilities of four atoms directly attached to the asymmetric carbon atom. The explanation is shown to be applicable also to some of related polym

ISSN:0449-296X    

DOI:10.1002/pol.1971.150091210

出版商:John Wiley&Sons, Inc.    

年代:1971

数据来源: WILEY