摘要:

AbstractFive methods were modified to test for interactions between binder and filler of composite solid propellants. Methods based on uncured binder or model compounds were rate of solution of binder from composite mixtures; centrifugal separation of binder from the filler; of composite mixtures; measurement of the contact angle between binder and filler; and adsorption of binder or model compounds by filler from solution. Stress–strain–birefringence was measured on cured binders containing small amounts of filler. In addition to the polymers used as binders and the model compounds, three physical forms of aluminum, and the additives tris [1‐methylaziridinyl] phosphine oxide (MAPO) and a polysebacate of methyl‐N‐diethanolamine were included in the study. The filler was ammonium perchlorate in all experiments. The polysebacate was an effective adhesion improver in the polyurethane–ammonium perchlorate composite. MAPO was not as effective in the system polybutadiene–ammonium perchlorate. Fibrous forms of aluminum result in a weaker propellant then does powdered aluminum. Nonfunctionally terminated polymers were poorer in adhesion, contact angel, and adsorption tests compared with carboxyl‐ and hydroxyl‐terminated types. The nonpolymeric model compounds yielded

ISSN:0021-8995    

DOI:10.1002/app.1974.070180101

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe adhesion between ammonium perchlorate filler and the polybutadiene rubber matrix was investigated. The aggregate composite was modified by surface pretreatment of the filler with various organofunctional silanes. For comparison, the adhesion of glass beads and glass powder, each coated with a fluorocarbon release agent, and carbon black were used as fillers in the cured polybutadiene matrix. Common testing methods used included the determination of Poisson's ratio, photographic analysis, and absorption of water. A new type of stress–strain analysis was introduced. Results closely agreed with established composite theory. The presence of methacryloxy‐ and amino‐functional silanes improved adhesion to the resin system. Epoxy‐ and vinyl functional silanes proved to be detrimental at the filler–rubber interface. A major function of the coupling agents appears to be to eliminate the weak boundary layer of surface moisture on the filler

ISSN:0021-8995    

DOI:10.1002/app.1974.070180102

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

年代:1974

数据来源: WILEY

摘要:

AbstractEmpirical correlations of flow properties of poly(vinyl chloride) were made using data reported by a number of investigators. Correlation was made by plotting the reduced variable viscosity η/η0versus\documentclass{article}\pagestyle{empty}\begin{document}$ (\eta _0 \dot \gamma \bar M_w )/(_\rho RT) $\end{document}or\documentclass{article}\pagestyle{empty}\begin{document}$ (\eta _0 \dot \gamma \bar M_w ^{0.5} )/(_\rho RT) $\end{document}for unplasticized PVC and versus\documentclass{article}\pagestyle{empty}\begin{document}$ (\eta _0 \dot \gamma \bar M_w ^{0.5} )/(_\rho RTW_2 ^a ) $\end{document}with polymer concentration,W2, for PVC containing plasticize

ISSN:0021-8995    

DOI:10.1002/app.1974.070180103

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

年代:1974

数据来源: WILEY

摘要:

AbstractSynthesis of zirconium oligomeric polythioethers was effected using aqueous solution and interfacial techniques:The products are insoluble in all tried solvents and possess ZrOH endgroups but no detectable quantities of RSH, ZrCl, or ZrNEt

ISSN:0021-8995    

DOI:10.1002/app.1974.070180104

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe viscosity of concentrated (17.5 g/dl) solutions of cellulose acetate in 11 single solvents and in four binary solvent mixtures was related to a thermodynamic measure of solvent power. In single solvents, the specific viscosity varied from 4600 in dimethyl sulfoxide to 78,000 in diacetone alcohol, with the specific viscosity increasing with decreasing abolute value of the partial molar free energy of dilution. This behavior can be accounted for by the hypothesis that the number of chain entanglements increases with decreasing solvent power. In solvent mixtures, the specific viscosity often attains a minimum value at a composition where the average solubility parameter locus is near the center of the solubility region of the polymer.

ISSN:0021-8995    

DOI:10.1002/app.1974.070180105

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe design and operation of an automated density balance are outlined. Diverse uses for this equipment are discussed.

ISSN:0021-8995    

DOI:10.1002/app.1974.070180106

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

年代:1974

数据来源: WILEY

摘要:

AbstractViscoelastic properties of the BBL ladder polymer were determined by a dynamic mechanical technique for the temperature range −150°C to 250°C and at frequencies of 3.5, 11, and 110 Hz. A secondary loss dispersion centered at −50°C (at 110 Hz) was discovered which probably arises from an in‐chain relaxation mechanism. The loss dispersion resembles β‐transitions found in more conventional polymers in intensity (maximum tan δ = 0.035), activation energy(E= 19,000 cal/mole), and in its close relation to the high‐temperature mechanical properties of the polymers. Only slight changes in the low‐temperature loss peak cause significant increases in brittleness. It is proposed that such changes, produced by a variety of environments, result from random chain scission at imperfection points in the ladder structure. For this reason we conclude that improving the environmental stability of BBL is of prime importance in its further development for speci

ISSN:0021-8995    

DOI:10.1002/app.1974.070180107

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

年代:1974

数据来源: WILEY

摘要:

AbstractA study has been carried out of the relationship between polymer orientation and dyeing behavior using a specially prepared range of nylon 66 samples varying only in orientation and five dyes normally showing varying degrees of sensitivity to physical variations in nylon. Integral diffusion coefficients have been calculated using Crank's finite dyebath equation from appropriate rate of dyeing data. Evidence has been produced which suggests that except with dyes of low molecular weight, i.e., dyes insensitive to physical variations in the nylon, a diffusional interaction between diffusing dye molecules exists which leads to a variation in the concentration dependence of the diffusion coefficient with fiber orientation. The length of the diffusing dye ion has been shown to be of decisive importance in this interaction.

ISSN:0021-8995    

DOI:10.1002/app.1974.070180108

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe tracer diffusion coefficients of three S‐35‐labeled dyes in nylon 6 film have been determined. The diffusion coefficients show marked concentration dependence, but this takes a form different from that shown by chloride ions in a related study. It is not possible to explain the data on the basis of electrostatic factors as in earlier work in which diffusion was accompanied by a free‐energy change. A diffusional interaction between dye molecules is postulated which takes the form of a free‐volume saturation effect leading to an upper limiting diffusion coefficient at adsorption levels which depend upon the polymer order and the characteristics of the diffus

ISSN:0021-8995    

DOI:10.1002/app.1974.070180109

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe efficiency of three commercial ultraviolet absorbers, a 2‐hydroxy benzophenone, a 2‐hydroxy benzotriazole, and a nickel chelate, in preventing the photo‐oxidation of polystyrene films has been measured. When compared with the calculated screening and phosphorescence quenching efficiency, it is found that (i) the nickel chelate protects the substrate by UV screening alone and is a poor photoprotector, and (ii) the 2‐hydroxy benzophenone and 2‐hydroxy benzotriazole are more efficient photoprotectors and protect by triplet energy transfer from excited polymer carbonyl impurity groups in addition to UV

ISSN:0021-8995    

DOI:10.1002/app.1974.070180110

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

年代:1974

数据来源: WILEY