摘要:

AbstractEthyl acrylate was readily grafted from an aqueous solution onto cellophane film previously treated in a corona discharge at atmospheric pressure. The effect was found when the corona treatment was carried out not only in air but also in pure nitrogen. The observed grafting was not promoted but depressed by the presence of ferrous ion, which indicated that peroxide radicals were not initiating the graft. A high grafting efficiency was obtained, and the grafted surface was covered with a smooth uniform layer of polymer.

ISSN:0021-8995    

DOI:10.1002/app.1976.070200301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe copolymer compositions as a function of molecular weight for three poly(styrene‐co‐vinyl stearate) copolymers of widely varying conversion were determined. A combined gel permeation chromatography–infrared spectroscopy method was used. Theoretical changes in copolymer composition were calculated using reactivity ratios. Comparison of the calculated and observed changes in copolymer composition as a function of molecular weight showed qualitative agreement. However, the observed changes in composition were significantly larger than those calcu

ISSN:0021-8995    

DOI:10.1002/app.1976.070200302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe details of an infrared technique standardized to analyze cotton–polyester blends of different compositions are reported. It is observed that particle size plays a very important role in the peak intensity of the 1725 cm−1band (CO stretching) in polyester, the absorption band recommended for analysis of cotton–polyester blends. However, the product of the band width and peak intensity is found to be dependent on particle size to a lesser extent and hence is a more reliable parameter in the measurement of percentage composition. It has further been shown that the method of sample preparation can affect the band width and hence the results. A suitable sample preparation procedure is, therefore, described whereby an accuracy of ±3% in the estimation of polyester content in a given blend can be

ISSN:0021-8995    

DOI:10.1002/app.1976.070200303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractEvidence is presented that the apparent diffusion coefficient of one penetrant can be increased by competition from another penetrant for the same adsorption sites in polyester. The competition is governed by the relative diffusivities of the penetrants and their affinities for the adsorption sites.

ISSN:0021-8995    

DOI:10.1002/app.1976.070200304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractExperiments were designed to study the role of the solvent in the transport of a solute through a solvent‐swollen polymer membrane. A single solute (an organic dye), a single polymer (cross‐linked natural rubber), and 24 different organic solvents were used for this purpose. The solute diffusion coefficientDwas calculated from the measured permeabilityPand distribution coefficientK, and was compared to the diffusion coefficient of the solute in the pure solvent. The main parameters of the solvent were shown to be its viscosity and the degree it swells the polymer. At high swelling, the results are in agreement with a model that pictures the resistance to solute diffusion as hydrodynamic interaction with the solvent while the polymer acts as an obstruction that increases the tortuosity of the diffusion path. At very low swelling, the diffusion coefficient approaches an asymptotic limit which is independent of solvent viscosity. However, even with as low as 10% solvent, some effects of viscosity are still seen. These results are discussed in terms of a quantitative theory for the obstruction effect proposed by Meares and compared to other literature d

ISSN:0021-8995    

DOI:10.1002/app.1976.070200305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractStudies have been made on the effect of the molecular weight ofp‐N,N‐dimethylaminostyrene homopolymers and the composition of its copolymers with styrene on the glass transition temperature. Comparative thermal degradation studies have been made on polystyrene andp‐N,N‐dimethylaminostyrene polymers by thermal analytical methods (TG, DTA, and DSC). The differences in thermal stability and overall thermal degradation behavior of the two systems are discussed in terms of the differences in their degradation mec

ISSN:0021-8995    

DOI:10.1002/app.1976.070200306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe monomerp‐N,N‐dimethylaminostyrene has been synthesized fromp‐N,N‐diethylaniline and homopolymerized and copolymerized with styrene using 2,2′‐azobisisobutyronitrile as free‐radical initiator. The polymers have been characterized by thermal analysis (DTA, DSC, and TG). Glass transition temperatures have been measured and activation energies for degradation in nitrogen have been established by a variety of methods for compara

ISSN:0021-8995    

DOI:10.1002/app.1976.070200307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe monomerm‐N,N‐dimethylaminostyrene has been synthesized from acetophenone and homopolymerized and copolymerized with styrene, using 2,2′‐azobisisobutyronitrile as free‐radical initiator. The polymers have been characterized by thermal analysis (DTA, DSC, and TG). Glass transition temperatures have been measured and activation energies for degradation in nitrogen have been established by a variety of methods for comparative

ISSN:0021-8995    

DOI:10.1002/app.1976.070200308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractHomopolymers ofp‐N,N‐dimethylaminostyrene and copolymers with styrene have been subjected to thermal analysis studies in air. Molecular weight and copolymer composition have been shown to influence the stability of the polymers and the shape of the TG and DSC curves obtained under dynamic conditions. Mechanisms to account for this behavior based on the anti‐oxidant effect of the chain‐boundp‐N,N‐dimethylamino substituent ar

ISSN:0021-8995    

DOI:10.1002/app.1976.070200309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractPoly(vinyl alcohol) multifilament yarn was modified by reaction with hexamethylene diisocyanate. The effects of reaction variables such as time, temperature, concentration of reagents, solvent, and atomosphere were studied. The role of solvent appears to be very important in the reaction. Dimethylformamide, on account of its swelling power, proved better than the solvents benzene, toluene, and dioxane. Physical properties of modified fibers were compared with those of the parent. Moisture regain of the modified samples decreased with increasing add‐on percent. The elastic recovery was not improved, and there was little effect of the HMDI treatment on mechanical properties. The thermal stability of poly(vinyl alcohol) modified with diisocyanate with small add‐on was slightly impro

ISSN:0021-8995    

DOI:10.1002/app.1976.070200310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY