摘要:

AbstractIt was found that acrylonitrile is polymerized by UV irradiation in the presence of triphenylphosphite under conditions where acrylonitrile alone does not polymerize. The rate of polymerization was found to be proportional to the monomer concentration, the phosphite concentration, and the light intensity. It was thought that a donor‐acceptor complex formed between triphenylphosphite and acrylonitrile absorbs light and initiates the radical polymerizatio

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100711

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractTriad and tetrad tacticities of poly(methyl α‐chloroacrylate) and poly(methyl α‐chloroacrylate‐β‐d1) were determined by nuclear magnetic resonance (NMR) spectroscopy. Methyl α‐chloroacrylate‐β‐d1and its polymer were first synthesized. Isotactic poly(methyl α‐chloroacrylate) was prepared with ethylmagnesium chloride‐benzal‐acetophenone in combination as catalyst. The syndiotacticity of radically polymerized polymers increased with decreasing polymerization temperature. For radical polymerization, enthalpy and entropy differences between isotactic and syndiotactic additions were calculated to give ΔH i*− ΔH s*= 850 cal/mole and ΔS i*− ΔS s*= 0.93 eu. The stereoregularity of the polymer prepared with phenylmagnesium bromide catalyst was analyzed in fairly good agreement with first‐order Markov statistics, while polymerization with fluorenyllithium seems predominantly to proceed by a mechanism similar to free‐radical mechanism. Stereoregularity‐controlling power f

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100712

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractCopolymers of butadiene, isoprene, and chloroprene with 4‐chlorostyrene have been prepared with hydroxyl and carboxyl terminal groups, 4,4′‐azobis(4‐cyano‐n‐pentanol) and 4,4′‐azobis(4‐cyanovaleric acid), respectively, being used as the initiators. The copolymerizations were carried out in dioxane solution to give liquid prepolymers of low molecular weight capable of undergoing conventional chain‐extension reactions and suitable for utilization as encapsulating resins. Preparative and prepolymer characterization prope

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100713

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractThe monofunctional acetylenes, phenylacetylene andm‐ethynyltoluene, were each copolymerized with diethynylbenzene in a 1:1 mole ratio by using TiCl4/3AlEt2Cl as cyclotrimerization catalyst. The aromatic polymers which were produced were polydisperse with a molecular weight of ∼10,000. Variation of catalyst concentration had no effect on the molecular weight profile. An excess of bifunctional acetylene produced some insoluble gel but when some of the monofunctional acetylene was withheld and added only after an initial molecular weight build‐up by the excess bifunctional acetylene, soluble polymers with molecular weights of approximately 50,000 were obtained in high yield, provided the overall ratio of mono‐ to bifunctional acetylene was maintained at 1:1. The resulting polyphenylenes were highly soluble in benzene and chlorinated solvents but gave brittle films. This was attributed to a highly branched structure resulting from a lack of specificity by the catalyst. Thermogravimetric analysis showed the polymers to have high thermal st

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100714

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractPolymerization 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐β‐D‐mannopyranose at −60°C with phosphorus pentafluoride (0.9 mole‐%) gives stereoregular 2,3,4‐tri‐O‐benzyl‐[1 → 6]‐α‐D‐mannopyranan with substantially higher viscosity ([η] = 2.8 dl/g) than the corresponding gluco‐ and glactopyranan derivatives prepared similarly. Debenzylation with sodium in liquid ammonia produces stereoregular [1 → 6]‐α‐D‐mannopyranan of viscosity up to [η] = 0.54 dl/g. Stereoregular 2,3,4‐tri‐O‐acetyl‐[1 → 6]‐α‐D‐glycopyranans are most simply prepared by acetylation of the corresponding crude [1 → 6]‐α‐D‐glycopyranans obtained directly from the debenzylation reaction. The galactan is extremely difficult to acetylate by conventional methods if isolated in a pure form. Physical and spectral properties of these highly stereoregular synthetic 2,3,4‐tri‐O‐acetyl‐[1 → 6]‐α‐D‐glycopyranans are presented. Optical rotary dispersion curves of 2,3,4, tri‐O‐acetyl‐[1 → 6]‐α‐D‐glycopyranans show small Cotton effects in the 200–230 nm region, superimposed on strong background rotation. Circular dichroism spectra show a single n →*acetate absorption band for each polymer. The sign of the band appears to be determined largely by the C‐2 configuration. Stereoregular 2,3,4‐tri‐O‐acetyl‐[

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100715

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractA study was made of the solid‐state polymerization of built‐up monomolecular layers of vinyl stearate. Polymerization was initiated by exposing the samples to60Co γ‐radiation. The reactions were followed by multiple internal reflection infrared spectroscopy. The structure of the multilayer monomer and polymer was studied by x‐ray diffraction. Surface properties of the multilayers were studied by contact‐angle measurements. Results showed that, under the proper conditions, monomer multilayers of vinyl stearate could be polymerized to virtually 100% completion. Reaction was favored by higher irradiation temperatures, larger doses of radiation, and by higher reaction temperatures. The x‐ray diffraction photographs indicated that both the monomer and polymer multilayers possessed some single crystal character. Contact‐angle measurements indicated that the molecules in both the monomer and polymer multilayers were

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100716

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractThe vapor‐phase radiation graft polymerization of styrene, methyl methacrylate, and acrylonitrile on surface of dispersed filler (magnesium oxide) was studied. It was established that the polymer graft films are irreversibly chemically bound to the surface, cover it with a discontinuous layer which leaves a part of the surface free from polymer in the form of a mosaic. The grafting modifies the surface and increases the compatibility of filler with the polymer mediu

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100717

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractThe reaction of phthalic thioanhydride and aniline yieldedN‐phenylphthalimide quite readily. The reaction was strongly dependent on solvent and temperature. Various additives tried as a reaction promoter were almost ineffective. By the extension of the model reaction, polyimides were prepared in a simple one‐step synthesis from pyromellitic dithioanhydride and aromatic diamines in dimethylacetamide or other solvents. Polymers with inherent viscosity up to 0.3 in concentrated sulfuric acid were obtained in approximately quantitative yi

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100718

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractThe cotrimerization of phenylacetylene and diethynylbenzene yields high molecular weight highly branched polyphenyls. The polymers obtained have the usual thermal stability. They are soluble in common chlorinated solvents.

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100719

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY

摘要:

AbstractThe reaction of 4‐vinylpyridine (4‐VP) with acylating agents in diethyl ether was investigated. Acetyl chloride (AcCl) and trifluoroacetic anhydride [(TFAc)2O] yield colored oligomers with 4‐VP, denoted P‐4VP—AcCl (III) and P‐4VP—(TFAc)2O (IV). Nuclear magnetic resonance spectrometry was used to analyze these products. A structure (XII), representing a random copolymer resulting from 1,2‐polyaddition and 1,6‐polyaddition to 4‐VP, is proposed for III and IV. Alternative mechanisms which explain these observations are discussed. Acetic anhydride (Ac2O) does not acylate 4‐VP. It is proposed that this result is caused by the inability of Ac2O to quaternize 4‐VP as an initial step le

ISSN:0449-296X    

DOI:10.1002/pol.1972.150100720

出版商:John Wiley&Sons, Inc.    

年代:1972

数据来源: WILEY