摘要:

AbstractThe extraordinary physical properties exhibited by block polymers have been ascribed to the presence of a multiphase microstructure in which the higher modulus phase acts as a quasi‐crosslink or filler particle. Recently, the optical examination of these materials combined with mechanical testing has given investigatiors new insight into this complex morphology. In this investigation, simultaneous stress, strain, and birefringence data have been collected on a block polyester urethane elastomer. Stress‐softening is observed in cyclic stress‐strain experiments, giving rise to significant hysteresis in the stressstrain and birefringence‐stress curves. In these tests, prestrain causes a large increase in the stress‐optical coefficient, but has little effect on the strain‐optical coeffcient. As the temperature is increased, the strain‐optical coefficent decreases while the stress‐optical coefficient increases with the latter exhibiting a larger temperature dependence than predicted by the kinetic theory of rubber elasticity. The good agreement between the mechanical‐optical response of polyester urethanes and that of other block polymer systems provides further evidence of their morphol

ISSN:0032-3888    

DOI:10.1002/pen.760090602

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe stress concentration and effective flexure stiffness of an ASTM V‐notch Izod specimen is excessive for most cases of plastics use. A more typical stiffness is that of a thin plate in two dimensional bending. Such can be approached with a larger radius and deeper V‐notch. Instead of a V‐notch, however, a double edge notch with the same radius and thickness at the root is recommended. The special advantage of the double edge notch is that the notch at the back edge reduces the energy loss due to the

ISSN:0032-3888    

DOI:10.1002/pen.760090603

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractSome properties of multilayered films are summarized in relation to the properties of the component materials. Polymers may be selected for co‐extrusion into layered films to obtain various combinations of properties, such as barrier, stiffness, heat sealability, optics, and toughness. Properly chosen combinations of high and low modulus materials exhibit mutual interlayer reinforcement. Permeabilities of multilayer films can be calculated from layer geometry and individual component propertie

ISSN:0032-3888    

DOI:10.1002/pen.760090604

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe physical optics of iridescent multilayered plastic films are analyzed theoretically relating the layer thickness, layer arrangement, and refractive index difference between layers to the reflection spectra for light at normal incidence. Very vivid iridescent and metallic‐appearing films may be made by proper control of layer distributio

ISSN:0032-3888    

DOI:10.1002/pen.760090605

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe changes occurring when polythene melts are subjected to shear, have been investigated using a rotating bob fitted into a ram extruder. In addition to chain scission, low density polythene exhibits reversible changes in mechanical and viscoelastic properties. The magnitude of the changes is controlled by total shear strain, and is related to molecular weight and long chain branching. The mechanism appears to be one of reversible disentanglement operating mainly on the large highly branched molecules. The work is relevant to various extrusion processes and to other long‐branched polymer

ISSN:0032-3888    

DOI:10.1002/pen.760090606

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractA machine to measure the creep deformation of plastics under uniaxial compressive loads is described. The problems associated with accurate creep testing in compression, primarily the application of a uniform stress to the specimen and the measurement of the resultant strain, receive particular attention. For the specimen geometries used, the effect on the measured strain of frictional restraints at the specimen ends is negligible provided the strain measurement is made with an extensometer attached to the specimen.The effect of fabrication techniques on the deformation behavior of polytetrafluoroethylene (PTFE) has been examined. Sintering time and temperature are found to be the most significant variables in the processing of PTFE. A comparison of uniaxial tensile and compressive creep data has shown that the non‐linear viscoelastic behavior of the material extends into the low strain regio

ISSN:0032-3888    

DOI:10.1002/pen.760090607

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractSpherulitic films of polybutene‐1 have been stressed under biaxial tension. Direct microscopic observations indicate that the deformation is localized at the spherulite centers and at the intersections of boundaries in agreement with previous results obtained with linear polyethylene. The results demonstrate an increasing tendency for brittle failure with decreasing molecular weight. Effects of surfactants and solvents are also presente

ISSN:0032-3888    

DOI:10.1002/pen.760090608

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractSilane coupling agents containing organo‐functional and alkoxy groups are applied to glass fiber reinforcements from an acid solution commercially. It is found that finely divided soda glass suspended in a methanol‐water solution of various silanes promotes hydrolysis without the presence of an acid catalyst. When acid is present in addition to the glass, as in commercial application baths, rate of hydrolysis is lower than with either acid or glass alone. There is evidence that basic glass components catalyze hydrolysis. Further work under commercial application conditions is indica

ISSN:0032-3888    

DOI:10.1002/pen.760090609

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThis investigation deals with the fatigue behavior of a group of thermoplastics fortified with discontinuous glass fibers dispersed by an injection molding process. The thermoplastics included nylon, polystyrene and polyethylene reinforced with short (1/8 in.) and long (1/2 in.) glass fibers.Several aspects of the fatigue behavior are included in the study. First, classical S–Ncurves were generated under fluctuating tension withR= 0.05 to show the loss of strength due to cyclic load application. Next, the extent of progressive fatigue damage was established by measuring the residual strength after cyclic loading. Finally, hypotheses pertaining to the fatigue mechanisms operative in all four materials were made based on microscopic examinations of sections removed from fatiguedamaged specimen

ISSN:0032-3888    

DOI:10.1002/pen.760090610

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe dynamic thermal stability of rigid PVC resin compositions as determined from Brabender torque rheometer tests has a linear relationship of stability time and torque from which a practical measure of processability at a fixed torque can be derived. The stability time at 1500 m‐g torque,t1500, has been used to characterize differences between PVC homopolymer and copolymer resins in tin, calcium‐zinc, lead, and bariumcadmium stabilizer systems. In every case, the vinyl chloride‐propylene copolymers are unique in giving substantial process‐ability advantages.The logarithm of stability time at a fixed torque,t1500, is a linear function of intrinsic viscosity, [η], for PVC homopolymers, giving a single line function corresponding to the expression logt1500=A+B[η]. The constants,AandB, vary with each of the four stabilizer systems, and are related to the effectiveness of the particular formulations used.The ratio oft1500for copolymers to the basict1500value for PVC homopolymers at the same intrinsic viscosity (molecular weight) is a practical measure of relative processability,trel, which is characteristic of PVC resin types and independent of stabilize

ISSN:0032-3888    

DOI:10.1002/pen.760090611

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY