摘要:

AbstractAn investigation of the viscous flow properties of mixtures of low molecular weight materials, such as lubricants and plasticizer, with PVC has been carried out. In all examples studied the PVC exhibited a discontinuity in flow with increasing temperature. This was interpreted as a phase change in the melt. A diffusion fractionation of the low molecular weight species was used to rationalize the shear rate dependent viscous behavior of these melts.

ISSN:0032-3888    

DOI:10.1002/pen.760090202

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractRe‐examination of our work on internal plasticization of polyvinyl chloride leads us to suggest a number of guidelines in the synthesis of internally plasticized PVC with optimum combination of strength and low temperature properties: (1) use of comonomers of solubility parameter around 8.5 or 10.5, (2) use of a high molecular weight (long chain) comonomers in a low molar ratio, and (3) their non‐uniform incorporation in the PVC ch

ISSN:0032-3888    

DOI:10.1002/pen.760090203

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThis investigation considers a hypothetical three‐phase ordered composite to permit the design of a new material both stiffer and tougher than the matrix phase alone. The required elastic solution is greatly simplified and was based on a single layered inclusion in an otherwise infinite matrix under uniaxial tension. The solution presented is exact and generalized to accommodate any number of concentric layers of different thickness and compositio

ISSN:0032-3888    

DOI:10.1002/pen.760090204

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractIt is postulated that property gradients exist at the interface forming an “interphase” between the insert and the matrix. Such gradients might be caused by partial solubility and diffusivity of the two phases comprising a composite. For simplicity, the “interphase” is replaced by a shell exhibiting averaged properties (Eshell= 1/2Einsert+ 1/2Ematrix, etc.). An exact linear elastic solution was employed to evaluate stress fields throughout all regions. The possible effect of the “interphase” and its thickness on several physical properties of the composite are evaluated in terms of the particular st

ISSN:0032-3888    

DOI:10.1002/pen.760090205

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractBiaxial creep tests have been performed on thin‐walled tubes of polymethyl methacrylate at 116°F and 50% R.H. The tubes were loaded radially up to a specified stress state, which was then maintained for a finite time. Additional tests involved a constant stress state for a period Δt1, after which the specimen was rapidly subjected to a second stress state which was maintained for a period Δt2. The experimental apparatus and procedure are described. The results for the range of stress, temperature, and time investigated show: 1) the creep behavior can be described by the form ϵ = ϵ0+mtn, where ϵ is the strain, ϵ0is the time‐independent portion of the strain, andmandnare constants; 2)nappears to be independent of stress state in the fourth quadrant (−σzaxial stress, +σθtangential stress), andmis a linear function (log‐log) of effective stress. In the first quadrant (+σz+σθ), the values ofmandnare dependent on stress state, the constantmbeing also dependent on effective stress. Since two measurements are made for tangential strain ϵ0, a description of the deformation can be obtained. Some results of pre‐strain history and frac

ISSN:0032-3888    

DOI:10.1002/pen.760090206

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractA number of polymers have been “cold” extruded (i.e. at temperatures well below their normal melting temperatures) by the application of relatively high pressures. In all cases extrudates of relatively large cross‐sectional area have been produced, and non‐circular cross‐sections have also been extruded. The extruded products has been evaluated and the results discussed. In general it has been found that whilst extrusion gives an oriented product, the increase in tensile modulus is much less than for a comparably drawn fibre. This phenomenon has been discussed in terms of the changes in crystalline structure produced by

ISSN:0032-3888    

DOI:10.1002/pen.760090207

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractAttempts to use low‐cycle fatigue techniques derived from the work of Coffin and Manson to predict the fatigue performance of six diverse structural plastics are discussed. Through an analysis of dynamic property and thermal behavior studies of polymer samples in reversed‐tension fatigue, an improved model for the polymer fatigue process has been proposed. Laboratory test data are presented illustrating the relationship between the various mod

ISSN:0032-3888    

DOI:10.1002/pen.760090208

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractEpoxy‐Versamid specimens were loaded in tension up to failure at different constant strain‐rates and temperatures. Results revealed three modes of behavior prevailing at different temperature‐strain‐rate regions and associated with brittle, ductile and rubbery failure modes. The ductile region was found to be confined within a narrow band on the temperature‐strain‐rate plane, and is characterized by a yield plateau in the stress‐strain curve and by linear dependence of yield stress on log strain rate and temperature. Yield strain seems to be almost unaffected by strain‐rate, but decreases slightly with temperature rise.Analysis indicated that experimental data within the ductile region are consistent with Eyring's formulation for non‐Newtonian viscoplastic flows. It leads to the evaluation of the “apparent activation energy” and activation volume for the two epoxy systems tested.Comparison with previous work indicates that the above parameters as well as yield stress and elastic modulus tend to increase with the decrease of the Versamid

ISSN:0032-3888    

DOI:10.1002/pen.760090209

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractAn analog computer‐polymerizer system is described which polts continually the rate of polymerization in percent per hour and the total percent conversion. Computer components and their functions are briefly described and the polymerization vessel with its control instruments are shown. Methods of calibration and accuracy of the system are discussed.Polymerization rate curves for various initiators at various temperatures are presented. These curves show the typical autoacceleration of precipitating systems and the rate increase due to the gel effect. Experimental evidence is presented to explain the pressure drop seen in these curves at 70–75% convers

ISSN:0032-3888    

DOI:10.1002/pen.760090210

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760090201

出版商:Society of Plastics Engineers, Inc.    

年代:1969

数据来源: WILEY