Measurement and Prediction of Anisotropy in Injection Moulded PP Products

Author:

Jansen K. M. B.1

Affiliation:

1. Department of Mechanical Engineering, Twente University, The Netherlands

Abstract

Abstract Exact knowledge of anisotropy in thermal and mechanical properties of moulded articles is important since it is directly related to undesired phenomena like warpage. In this study careful measurements of the coefficients of thermal expansion, elastic moduli, Poisson constants and linear compressibilities showed that the anisotropy of these properties was about 10%, for injection moulded polypropylene plates. A simple composite model was proposed which could predict all thermal and mechanical properties mentioned above from data of the amorphous and crystalline phases. The degree of crystallization, skin thickness and average orientation of the fibrillar precursors are the main input parameters. It turned out that although individual values were slightly over or underpredicted, the amount of anisotropy was usually predicted correctly. The only prediction which disagreed with the measurements was that of the coefficient of thermal expansion, which was measured to be larger in flow direction than in width direction. The changes of shrinkage and shrinkage anisotropy along the flowpath were studied experimentally for different processing conditions. The most remarkable observations were that variations in injection velocity only affected width shrinkage, while melt and mould temperatures specifically acted on length shrinkage. Holding pressure, on the other hand, affected both length and width shrinkage with the same amount.

Publisher

Walter de Gruyter GmbH

Subject

Materials Chemistry,Industrial and Manufacturing Engineering,Polymers and Plastics,General Chemical Engineering

Cited by 28 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3