摘要:

AbstractThe development of impact polystyrene and types of processes used is traced from its inception. Our accidental discovery of the process has resulted in the process being termed unique in that no other commercial polymerization has a like phenomenon that occurs in the shearing agitation step. The prior art and patent picture, before and after the issue of the Dow basic patent, is discussed. The litigation that has centered around the patent is reviewed. Information presented shows that this basic process for impact polystyrene has experienced an unusual degree of commercial success and has led to this family of plastics becoming of major commercial importance. These impact plastics have been accepted and used on a global basis.

ISSN:0032-3888    

DOI:10.1002/pen.760140102

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractBy incorporating the spectroscopic techniques of reflection‐absorption and internal reflection in the infrared region, we have been able to define and characterize overall chemical changes occurring at a metal‐polymer interface. Our initial studies have concentrated on the oxidative degradation of metal‐polymer systems. These systems are of particular importance because of the common need to retard the metal‐catalyzed degradation of the polymer. Preliminary results for copper‐polyethylene interfaces, models for polyolefin‐insulated cable, have shown the copper surface to be the site of the initial catalysis in the oxidation of the polyethylene. When copper deactivators are added to inhibit the oxidation, initial reactions between the copper surface and the inhibitor can be seen. The importance of these surface reactions highlights the necessity for studying th

ISSN:0032-3888    

DOI:10.1002/pen.760140103

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe concentration dependence of the rheological response of aqueous Separan solutions was measured. The shear and primary normal stress response in steady shearing flow, and the relaxation of shear stress following cessation of steady shear flow, were measured with four different polymer solution concentrations. Two different nonlinear constitutive equations, Bird‐Carreau and Meister, were used to analyse the data. The Bird‐Carreau model fit the steady shear data very well and the parameters obtained from steady shear data allow reasonable estimates of the stress relaxation of these systems. The Meister model provided a fit of the transient stress relaxation data and could be used to estimate the steady shear response. No quantitative molecular theory was developed in this work. However, the nature of the concentration dependence of the Bird‐Carreau parameters suggests that as the polymer concentration of aqueous Separan solutions decreases from 2.0 to 0.05 weight percent the solutions should be modeled less by an entangled network theory and more as slightly overlapping hydrodynamic units. The concentration where this behavior seems to be changing appears to be about 0.25 percent by weight of po

ISSN:0032-3888    

DOI:10.1002/pen.760140104

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe tensile behavior of oriented polybutadiene at 83°K is systematically studied as a function of strain rate and pre‐test orientation. Electron spin resonance studies of radical formation are made in conjunction with the mechanical tests. Three different modes of mechanical behavior are observed (brittle, crazing and a second ductile behavior without crazing), depending on test conditions. Radical formation is observed in association with the two ductile modes of behavior. The ESR spectra obtained are attributed to a combination of allyl radicals formed by chain scission between the α‐methylene groups and peroxy radicals. The relative quantity of the two radical species present is thought to be related to the ratio ofcis/trans‐isomerism. Stability of the radicals observed with time and with an increase in temperature is studied. Further studies are made of the quantity of environmental test gases absorbed during

ISSN:0032-3888    

DOI:10.1002/pen.760140105

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractWithin a normal operating range of extruders, it has been well established that the output increases nearly proportionally to the screw speed but the screw horsepower increases more than proportionally to the screw speed, making the screw HP difficult to predict. It has been also known in scale‐up of extruders that the output may be predicted with reasonable accuracy but the screw HP is difficult to predict. No sound theoretical or empirical method predicting screw HP in a scale‐up calculation has been offered heretofore. Since a screw performs solid conveying, melting and pumping (or metering) functions simultaneously, any theoretical analysis of screw HP has to consider all three extrusion theories; solid conveying theory, melting theory and pumping theory. In this paper, semi‐theoretical equations for predicting screw HP as a function of screw speed and size are developed. Experiments are conducted to test the utility of these equations and the implications of the experimental results on extrusion theories are disc

ISSN:0032-3888    

DOI:10.1002/pen.760140106

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractA highly sensitive thickness sensor has been developed which may be used as a continuously recording extensometer for rubbery materials. The application of the sensor for measuring volume changes in dewetting filled rubbers is also discussed. Further possible applications include the determination of Poisson's ratio on plastics.

ISSN:0032-3888    

DOI:10.1002/pen.760140107

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe temperature dependence of the mechanical properties of a 50/50 blend of PVAC and lightly crosslinked PMMA has been examined using the data of Kawaiet al.The shift distances, logaT, were generated by bringing the experimental data into coincidence on master curves calculated from a Takayanagi model whose parameters were varied in different regions of temperature. This method allows one to construct a master curve for a thermorheologically complex two‐phase material if the model and the mechanical properties of the constituent phases and their temperature dependence is known. The shift distances then provide insight into the intricate relations between the time and temperature dependence of the mechanical properties of the composit

ISSN:0032-3888    

DOI:10.1002/pen.760140108

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe chemo‐rheological behavior has been elucidated for three high temperature epoxy resins. Constant temperature and shear stress measurements were made on a modified Weissenberg Rheogoniometer. Curing behavior of various temperatures is unified by a time‐temperature superposition method. The curing rate of one resin, Ferro E‐293, is limited by the chemical reaction. The other resins, 3M PR‐286 and PR‐288, each have consecutively occurring reactions, both of which are diffusion limited. The chemo‐rheological information obtained for these materials is used to model viscosity for compression molding of hand‐laid

ISSN:0032-3888    

DOI:10.1002/pen.760140109

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractA simple theoretical model for flow in nonintermeshing twin screw extruders has been derived. The assumptions which in single screw extruders result in the “two parallel plates” model, in twin screw extruders result in the “three parallel plates” model. The flow rate equation can be expressed, for Newtonian fluids, in terms of drag and pressure flow terms, as in single screw extrusion theory, but each term is multiplied by a geometrical factor. This factor incorporates the effect of one screw on the drag and pressure flow terms of the other. The theoretical model was experimentally verified on a 1 inch diameter Bausano twin screw e

ISSN:0032-3888    

DOI:10.1002/pen.760140110

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractA series of rigid polyurethane foams of densities varying from 65 kg/m−3to 400 kg/m−3have been tested in compression as a function of rate and temperature. It has been found that a linear relation exists between density and modulus if the data is referred to a constantthermodynamictemperat

ISSN:0032-3888    

DOI:10.1002/pen.760140111

出版商:Society of Plastics Engineers, Inc.    

年代:1974

数据来源: WILEY