Published by De Gruyter

Volume 2 Issue 2

April 1987

Issue of International Polymer Processing

Contents
Journal Overview

Publicly Available March 2, 2022

Page range: 61-61

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Original contributions

March 2, 2022

On the Evaluation of Elastic Moduli of Bead-Filled (Thermoplastic) Systems

R. P. Hegler, G. Mennig, G. Vulpius

Page range: 63-71

Abstract

This study gives a detailed survey of the methods presently known for the evaluation of the elastic moduli of bead-filled composite materials. It examines the suitability of theoretical considerations, their scope of validity as well as possibly necessary theoretical modifications by means of experimental investigations of glass-bead-filled thermoplastics and related data found in the literature for globular-particle-filled materials. A prediction of the elastic moduli based on the properties of the components involved is possible without essential restrictions. The mechanical test results confirm the experimental findings known from the literature.

March 2, 2022

Thermal Analysis of PE Extended Chain Crystal of PE Extended Chain Crystal from Gel Spinning

A. Zhang, P. Lu, N. Yang, Z. Wu

Page range: 72-76

Abstract

It has been recognized that ultra-high strength and high modulus ultra-highly drawn Polyethylene (PE) fiber is produced from the formation of extended chain crystal. Nevertheless, whether extended chain crystal exists in gel spinning ultra-highly drawn PE fiber is still an unsettled question. In this work, decalin was adopted as a solvent for PE gel spinning. By means of thermal analysis, X-ray diffraction methods etc, the existence of extended chain crystal was explored. Reasons for confusion in previous studies of this problem were discussed. In PE fiber from 3 wt-°/o dope, extended chain crystal starts to form during draw ratios over 20. When draw ratio equals 42, the content of extended chain crystal roughly equals that of folded chain crystal. The melting point of extended chain crystal is 6°C higher than that of folded chain crystal. They are 145.5° C and 150° C to 152.5° C respectively. The latter would slightly rise with arise of draw ratio. Multi-crystallization behavior of annealed PE fiber was determined and discussed. It was also confirmed that there is a linear logarithm relationship between thermal shrinkage (internal stresses) and fiber moduli.

March 2, 2022

Properties of Liquid Crystal Injection Mouldings

G. Menges, T. Schacht, H. Becker, S. Ott

Page range: 77-82

Abstract

The suitability of liquid crystal polymers for the injection moulding process was pointed out at the time of their discovery. However, up to now, it has been assumed that the unmodified liquid crystal polymers were less suited to processing by injection moulding due to their distinct anisotropies. The direction of developments in the application of liquid crystal polymers was done mainly in another direction. We, however, have been concerned for more than four years now with this subject [3, 4, 5], even when our practical experiments could not be as comprehensive as we would wish, due to the limited availability of the raw materials. We have also been able to use this time to develop CAE programs which support the constructor in the design of injection moulds, whereby these programs enable the flow process to be simulated and therefore enabling the orientation to be seen at every point in the injection moulded part [6]. This is naturally particularly important for those materials in which the orientation of the molecules plays such a large part for the respective properties, as these are caused by the direction of the flows in the flow process. A changed runner position causes other orientations. More details should therefore be reported about our investigations to date.

March 2, 2022

Modification of PVC/CPE Blends with Coupling Agent and its Mechanism

C. Song, K. Li, S. Li

Page range: 83-87

Abstract

In this thesis, the modification of PVC/CPE blends was investigated. Addition of aromatic diamines into PVC/CPE blends as a coupling agent, greatly increases the impact strength of the blends. At the same time, other mechanical properties such as the tensile and bending strength can be improved as well. With the aid of solvent etching, the multiphase microstructure of the blends has been studied using a scanning electron microscope. The relationship between the microstructure and mechanical properties of the blends has been discussed. It was shown that there were coupling and crosslinking reactions in the blends with coupling agents. The concentration of the reacted coupling agent was related to the mechanical properties of the blends quantitatively. Using probability methods, the concentration of the coupled molecules formed in the blends can be calculated. The influence of the ratio of PVC to CPE on the coupling effectiveness can be predicted.

March 2, 2022

Mill Processability, Rheology and Structure Differences of Polyacrylate Elastomers

N. Nakajima, R. A. Miller, E. R. Harrel

Page range: 88-93

Abstract

Two commercial polyacrylate elastomers, one having epoxide (EP) crosslinking sites and the other ethylidene norbornene (ENB) were selected. It was demonstrated that the former was more difficult to mill-process than the latter. The viscoelastic properties measured at very small strain in shear oscillation indicated that the ENB polymer was more branched than the EP polymer. The gel determination by filteration confirmed this. The tensile stress-strain measurements were conducted at four different deformation rates. These data were treated according to the strain-time correspondence principle to see if this principle applies to the data of these samples. The data of EP polymer did not form a master curve, thus, the above principle is not applicable; at the larger deformation the strain-hardening tendencies were observed. This indicates that the EP polymer has a rather extensive long branching, a type of which usually results from a chain transfer reaction. The data of the ENB polymer, on the other hand, form a master-curve; that is, the strain-time correspondence principle is applicable, in spite of the presence of the large amount of gel. This means that the gel in the ENB polymer is microgel. The micro-gel in this case is polymer-latex particle, crosslinked during emulsion polymerization with a difunctional comonomer. Thus, in this work polymer rheology was effectively used to find a major difference in the polymer chain structure. In this way it was shown that the results of polymerization may be related to mill processability.

March 2, 2022

A Study of Fibre Attrition in the Processing of Long Fibre Reinforced Thermoplastics

R. Bailey, H. Kraft

Page range: 94-101

Abstract

A study has been carried out which demonstrates a technique for measuring long fibre lengths. This technique has been used successfully to discuss subtle differences in the fibre length distributions arising in a range of long fibre reinforced thermoplastics. These new materials were processed using a wide range of injection moulding conditions, including such variables as the injection speeds and the preplasticising screw back pressures. This work proposes mechanisms of fibre attrition in the injection moulding process and makes recommendations for the optimisation of fibre lengths in moulded articles. It is shown that alternative polymer matrices in the long glass fibre attrition. It is also demonstrated that this family of long fibre reinforced thermoplastics can be recycled successfully with considerable fibre length advantages over traditional extrusion precompounded short fibre compounds.

March 2, 2022

Flow of Rubber Compounds in a Plasticating Unit of a Reciprocating-screw Injection Molding Machine

R. Brzoskowski, J. L. White

Page range: 102-106

Abstract

An experimental study of the distribution of material and internal flow patterns in the cold feed screw injection molding machine for rubber compounds is presented. Experimental studies are carried out by vulcanizing rubber compounds in the screw of the plasticating unit at various positions in the molding cycle. The screw is then removed and the rubber strip unwound from the flights. It is found that transverse flow patterns begin at the feed port and proceed down the channel. Various kinds of starvation behavior are observed especially at low back pressures and with narrow feed strips.

March 2, 2022

Simulation of Tubular Film Extrusion of Polymer Melts

Non-Newtonian and Non-Isothermal Effects on Bubble Shpae

H. Yamane, J. L. White

Page range: 107-112

Abstract

A model of the tubular film process is presented which includes power law non-linear rheological behaviour with temperature and crystallinity dependent properties. The heat transfer modelling uses an experimental correlation for the heat transfer coefficient. It is shown that except at low activation energies of viscous flow, the power law exponents have little influence on bubble shape. For activation energies of viscous flow of 11 kcal/mol and more, the temperature dependence of rheological properties dominates bubble shapes at fixed drawdown ratios, blowup ratios and frostline heights. Low activation energies of viscous flow produced wine glass shaped bubbles, while high activation energies cause rapid increases in bubble radius after the die exit.

March 2, 2022

Study of the Void Structure of PAN Fiber by Small Angle x-ray Scattering and Spline Function

K. Jiang, Y. Wang, Z. Jiang, B. Qian

Page range: 113-117

Abstract

The voids in fibers, especially in wet spun fibers are a major factor of fiber structure which greatly affects the fiber properties. A lot of research has shown that the inner voids and surface imperfections were the main causes of strength decreases. Therefore it is very important to determine the void morphology development in fiber processing in order to obtain high quality as-spun fiber. In this paper we introduce a new method for the determination of void morphology using small angle x-ray scattering with a spline function method in which the average void size, size distribution and the related scattering power as well is obtained.

About this journal

International Polymer Processing offers original research contributions, invited review papers and recent technological developments in processing thermoplastics, thermosets, elastomers and fibers as well as polymer reaction engineering. For more than 25 years International Polymer Processing, the journal of the Polymer Processing Society, provides strictly peer-reviewed, high-quality articles and rapid communications from the leading experts around the world.
All articles are subject to thorough, independent peer review.
Editor: Polymer Processing Society

Volume 2 Issue 2

Issue of International Polymer Processing

Contents

On the Evaluation of Elastic Moduli of Bead-Filled (Thermoplastic) Systems

Abstract

Thermal Analysis of PE Extended Chain Crystal of PE Extended Chain Crystal from Gel Spinning

Abstract

Properties of Liquid Crystal Injection Mouldings

Abstract

Modification of PVC/CPE Blends with Coupling Agent and its Mechanism

Abstract

Mill Processability, Rheology and Structure Differences of Polyacrylate Elastomers

Abstract

A Study of Fibre Attrition in the Processing of Long Fibre Reinforced Thermoplastics

Abstract

Flow of Rubber Compounds in a Plasticating Unit of a Reciprocating-screw Injection Molding Machine

Abstract

Simulation of Tubular Film Extrusion of Polymer Melts

Non-Newtonian and Non-Isothermal Effects on Bubble Shpae

Abstract

Study of the Void Structure of PAN Fiber by Small Angle x-ray Scattering and Spline Function

Abstract