摘要:

AbstractThe direct silylation oftert‐butylphenol formaldehyde resins withN,O‐bis(trimethylsily)acetamide (BSA) has allowed a more complete analysis of these resins to be made with proton magnetic resonance (PMR) spectrometry. A quantitative determination of mixtures of the monomer, dimer, trimer, and tetramer may be carried out at 100

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141001

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractZwitterionic matrix stepwise polymerization of 4‐vinylpyridine (VP) using isotactic poly(acrylic acid) (i‐PAA) as a template results in formation of crystalline polycomplexes consisting of i‐PAA and of ionene (I):Depending on the concentration of VP and i‐PAA, the two types of crystalline polycomplexes can be prepared. The complex containing long ionene sequences withn≫ 2 is formed when [VP]0= [i‐PAA]0≥ 0.05M. At [VP]0= [i‐PAA]0⩽ 0.01M, the complex formed evidently contains the ionene dimer (n= 2). The x‐ray structures of the crystalline complexes are identical with those obtained by mixing of i‐PAA and the corresponding dimer and polymer presynthesized in the absence of the template. The matrix polymerization of VP in the presence of syndiotactic and atactic PAA at the same conditions results in formation of am

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141002

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe synthesis of 3‐methyl‐3‐butyl‐2‐azetidinone, which forms a polymer which is soluble in a number of common solvents including toluene, chloroform, and carbon tetrachloride, is described. Anionic polymerization, carried out in toluene solution in a calorimetric vessel, yielded for the heat of polymerization of a four‐membered lactam −19.1 kcal

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141003

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractGraft polymerization of styrene onto preirradiated poly(isobutylene oxide) was carried out at 25°C. The concentration of active sites for grafting was estimated by means of ESR and by the activation analysis of bromine atoms bound to the chain ends. Kinetic data such as differential amount of active sites (DACT), growth rate (GR), and average lifetime (τ) were obtained to calculate the molecular weight distribution of graft chains by the Monte Carlo simulation method. The number‐average molecular weight of the graft chain was calculated from the equation,Mn= 2GRτ (mw), which agreed well with the observed v

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141004

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effect of sonication on the morphology of microfibrils of chitins and celluloses was correlated with the polarity of their constituent chains. For given conditions, fibrillation of the microfibrils takes place when the polarity of the chains is antiparallel but not when it is parallel. If this correlation may be extended to cases of unknown structure, it permits an inference about the parallelity or antiparallelity of the chains of samples of both polymers where polarity cannot be determined directly.

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141005

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effect of temperature on the polymerization of diallyl phthalate was investigated in the temperature range of 80–150°C. The degree of polymerization increased slightly with temperature up to 100°C and then decreased; together with the results of primary chain length and the dependence ofRpon initiator concentration, these findings were interpreted in terms of the enhancement of the reinitiation ability of the allylic radical produced by the intramolecular chain‐transfer reaction and of the reactivity of the cyclized radical at elevated temperature. The tendency for cyclization became more marked with increasing temperature. The gel point was almost unaff

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141006

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractAromatic and aliphatic polybenzodipyrrolediones have been synthesized directly by the solution cyclopolycondensation of two dibenzylidenebenzodifurandiones with four different diamines in refluxingm‐cresol oro‐phenylphenol in the presence of boric acid. The polymerizations proceeded smoothly in a homogeneous solution and afforded the heterocyclic polymers having inherent viscosities as high as 1.0 almost quantitatively. All the polymers were readily soluble in a wide range of solvents, includingN‐methyl‐2‐pyrrolidone (NMP), hotm‐cresol, and hot pyridine. Tough, transparent, yellow films could be cast from NMP solutions of the polymers. Thermogravimetric analysis of the aromatic polybenzodipyrrolediones showed a 10% weight loss temperature of 460–500°C under nitrogen. The results also indicated that the aromatic polymers were somewhat less thermally stable than wholly aromatic polypy

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141007

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe EPR spectra of butadiene and of a mixture of butadiene and isobutylene in the presence of VCl4in the dark and with irradiation have been studied. The effect of light on butadiene leads to the formation of the radical‐cation of butadiene, similarly to isobutylene. In the mixture of both monomers, radical cations of isobutylene and butadiene are formed under the effect of light. Even if isobutylene is present in excess in the mixture compared to butadiene, the formation of the radical‐cation of butadiene still prevails. In presence of oxygen, with both butadiene and the isobutylene–butadiene mixture, peroxy radicals were detected. Cyclic polybutadiene was the main product of the photochemically initiated polymerization of buta

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141008

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractMethyl β‐(4‐aminophenyl)propionate was prepared and converted to a crystalline polyamide. The copolymerization of β‐(4‐aminophenyl)propionic acid or its methyl esters with caprolactam resulted in polyamides having wide ranges of crystallinity and thermal stability, depending on the chemical composition. Copolymers with 10, 50, 85, 90, and 95 mole‐% of caproamide sequences were shown by x‐ray and differential scanning calorimetry to be semicrystalline. The composition and thermal stability of the polyamides were studied by infrared spectroscopy and thermogravimetric analysis,

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141009

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractPoly(n‐heptaldehyde) has been prepared by anionic and cationic polymerization at −60°C in methyl cyclohexane. The anionic polymer is more crystalline and of a higher degree of isotactic structure than the somewhat rubbery but still crystalline cationic polymer. The polymers have been acetate‐endcapped to improve their thermal stability. Cationic polymer, when endcapped and purified, begins to degrade above room temperature; even crystalline anionic polymer degrades at a reasonable rate at 100°C. The crystallinity of poly(n‐heptaldehyde) is caused by crystallization of the acetalic main chain as well as the side chain. Two regions of melting have been recognized by DSC analysis and by microscopic observations. The low melting region between 80 and 100°C has been identified as the melting of the paraffinic side chains of poly(n‐heptaldehyde). It consists of three clearly definable endotherms at 78, 8

ISSN:0360-6376    

DOI:10.1002/pol.1976.170141010

出版商:John Wiley&Sons, Inc.    

年代:1976

数据来源: WILEY