ISSN:0032-3888    

DOI:10.1002/pen.760030302

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractThoughts on the development of theoretical approaches that would help make progress more certain in the polymer field are developed by a British polymer scientist of international reputation.

ISSN:0032-3888    

DOI:10.1002/pen.760030303

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractResin structures available from chlorinated polyethylene have been determined by studies of the infrared absorption spectra, and have been related to the glass transition temperatures and degree of crystallinity of the products. The relationships between chlorine content, molecular weight, glass transition temperature and a number of mechanical and rheological properties are described. Data are presented on the effect of blends of various resins in this series on glass transition phenomena. The stability of the resins to dehydrochlorination is discussed.

ISSN:0032-3888    

DOI:10.1002/pen.760030304

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractThe influence of channel curvature on flow through screw pumps and melt extruders is derived for infinite channel aspect ratios. Flow rate and horsepower relations for flow of Newtonian liquids are given as functions of design parameters. The results of this cylindrical theory are compared with those of conventional theories. Curvature factors converting the equations of the flat plate theory to those of the cylindrical theory are shown. Pressure distributions in screw pump channel are analyzed.

ISSN:0032-3888    

DOI:10.1002/pen.760030305

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractThe permeability of films to O2, CO2, and H2O vapor is reduced by drawing processes. The permeability data are compatible with the hypothesis that crystallinity reduces permeability because of (1) a decrease in the volume fraction of penetrable amorphous polymer; (2) a lengthening of the diffusion path by impenetrable barriers, presumably crystallites; and (3) a reduction in segmental motion within the amorphous volume. Analysis of the effect of molecular diameter on diffusion rate shows that the segmental motion within amorphous polypropylene regions is less than that in natural rubber.

ISSN:0032-3888    

DOI:10.1002/pen.760030306

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractMixing of viscous fluids in an annular channel is analyzed theoretically. Four basic mixing patterns are described which can be generated by altering the relative rotational velocities of the annular boundaries. Only one aspect of the mixing problem is isolated, i.e., reduction in striation thickness. Problems of front to back mixing to iron out variations of feed stream composition and mixing of solid particles are not considered. The theory was verified experimentally using molten polystyrene.

ISSN:0032-3888    

DOI:10.1002/pen.760030307

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractThe application of a free vibration technique to the study of the cross‐linking of an epoxy resin by an amine is demonstrated. Curing curves are presented showing the changes in dynamic mechanical flexural modulus and damping during reaction. At room temperature, the glass transition point is reached after a conversion of about 65% of the epoxide groups. Comparisons of the dynamic mechanical and infrared curing curves indicate a lowering of the reaction rate after this point is reached. Finally, an activation energy for the epoxy‐amine cross‐linking reaction is calcu

ISSN:0032-3888    

DOI:10.1002/pen.760030308

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractThis investigation studies the behavior of several cylindrical specimens of a Buna‐N elastomer subjected to compression impact by a finite mass. Initial strain rates fall in the range between 40/sec and 400/sec, with maximum nominal strains up to 0.4. It is shown that values of nominal stress, true and nominal strain, energy dissipation and impact duration can be correlated with elastomer geometry and initial kinetic energy by means of two parameters derived from an analysis of a linear viscoelastic model. Other sources of variability of elastomer behavior are discusse

ISSN:0032-3888    

DOI:10.1002/pen.760030309

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

Abstract1,2,2,‐Trifluorovinyl phenyl ether and 2,3,4,5,6,‐pentafluorophenyl 1,2,2‐trifluorovinyl ethers have been prepared, and the nucleophilic reactions of the phenoxide and 2,3,4,5‐pentafluorophenoxide salts with tetrafluoroethylene have been investigated. In general, it is some‐what difficult to control the reaction so as to produce the desired olefinic monomer. Under truly anhydrous conditions and when other sources of active protons are avoided, the olefin is the chief product if excess tetrafluoroethylene is used. The monomer produced is very reactive with phenoxide ions, and the diphenoxyolefins are the chief secondary products. Both monomers failed to polymerize under normal, free radical conditions. With boron trifluoride an oily material was obtained from the trifluorovinyl phenyl ether. High pressure and gamma rays converted both monomers into

ISSN:0032-3888    

DOI:10.1002/pen.760030310

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY

摘要:

AbstractThese compounds were synthesized by starting with the addition of the Grignard reagent of bromopentafluorobenzene to trifluoroacetaldehyde and chlorodifluoroacetaldehyde, respectively. The new alcohols, 2,3,4,5,6‐pentafluoro‐α‐(trifluoromethyl) benzyl alcohol and 2,3,4,5,6‐pentafluoro‐α‐(chlorodifluoromethyl) benzyl alcohol, are formed in good yield and undergo smooth conversion to (1,2,2,2‐tetrafluoroethyl) perfluorobenzene and (2‐chloro‐1,2,2‐trifluoroethyl) perfluorobenzene, respectively, in excellent yield when treated with sulfur tetrafluoride usingn‐pentane as diluent. The major pyrolysis product was identified as (2,2‐difluorovinyl) perfluorobenzene (α‐hydroheptafluorostyrene) and the minor one as perfluorostyrene. Perfluorostyrene was also synthesized in excellent yield by bromination of (1,2,2,2‐tetrafluoroethyl) perfluorobenzene and subsequent pyrolysis of the brominated derivative. The dehydrochlorination of (2‐chloro‐1,2,2‐trifluoroethyl) perfluorobenzene provided anothe

ISSN:0032-3888    

DOI:10.1002/pen.760030311

出版商:Society of Plastics Engineers, Inc.    

年代:1963

数据来源: WILEY