改善聚丙烯工程管材的耐疲劳性研究纺织工程专业论文.docxVIP

Abstract Study on improvement of the fatigue resistance of ziegler-natta isotactic polypropylene engineering mandrel pipes melt viscosities, mechanical properties and melting temperatures of the modified samples imply the successful grafting of the two monomers. The most important findings are the increase of alpha crystals, and the suppression of beta crystals, and improvement of fatigue resistance of Ziegler-Natta IPP. (3) The fatigue resistance of Ziegler-Natta IPP was also thought to be improved by controlling its aggregate state, and thus the idea was carried out by blending IPP with nylon 6 and alpha nucleating agent. The results showed that, the two additives effectively suppressed the formation of beta-crystal both during their processing and serving processes, and therefore the fatigue stability was improved as expected. A small amount of nylon 6 can keep the constant microstructure and mechanical properties at relatively short fatigue time while the alpha agent seems to lower the degree of crystalline and mechanical properties of IPP. The feature and innovation in the thesis are as follows: The high frequency fatigue test machine was designed and prepared, and the device is easy to operate, and can supply the multiple sample fatigue life curve for one test. The comparative test results showed that, although stress whitening appeared at the inner wall surface of the MAO isotactic polypropylene pipe after long time service, no alpha-beta crystalline transition happened; interestedly, the crystalline transition occurred while no visible changes was able to be detected for the Ziegler-Natta IPP ones after long time service. Keywords: isotactic polypropylene, grafting copolymerization, physical blending, torsional fatigue, crystal transition, fatigue resistance Author: LIU Zhonghua Supervisor at university: ZHU Xinsheng, Professor Supervisor in industry: REN Jun, Senior Engineer IV 目 录 HYPERLINK \l _bookmark0 第一章 概述 1 HYPERLINK \l _bookmark1 1.1 几种常见是聚合物管材特