温度梯度诱导全同立构聚丙烯在振动注塑成型过程中生成大量β26230;的研究

项目名称： 温度梯度诱导全同立构聚丙烯在振动注塑成型过程中生成大量β26230;的研究

项目编号： No.50873072

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 张杰

作者单位： 四川大学

项目金额： 35万元

中文摘要： 本课题对原有振动注射实验装置进行改造，研究了在注塑成型过程中，通过振动场和温度场的联合作用，诱导全同立构聚丙烯生成大量β26230;。并在此基础上研究了在不同成型工艺条件下成型试样的物理力学性能和凝聚态结构，通过优化成型工艺条件，使材料在达到自增强的同时实现了自增韧。 研究结果表明，在一定的加工条件下，通过振动场和温度场的耦合，可以诱导聚丙烯试样生成大量β26230;、实现了材料同时自增韧和自增强，如拉伸强度可以从静态试样的31.9MPa提高到46.7MPa,损耗模量从180MPa提高到330MPa。由于振动场产生的周期性剪切作用，试样由典型的皮-芯结构转变为多层次结构，各层的厚度及取向度都发生了明显的变化。首次在振动试样所特有的振动层发现了单核及多核柱晶、环带晶等特殊晶型，丰富了聚丙烯的结晶及加工理论。在对PP/MWCNT复合材料的振动注射研究中发现振动试样的导电性呈数量级增加，导电机理从隧道效应变为欧姆导电，试样内部形成了完善的导电通道。在项目的资助下，在包括Carbon、Polymer在内的国内外期刊上共发表学术论文28篇，其中SCI收录14篇；申请发明专利2项。

中文关键词： 振动场；β26230;；自增强；自增韧；温度梯度

英文摘要： The existing vibration injection equipment was improved in the project. Moreover, the formation of Isotactic Polypropylene containing majority of βP induced by the cooperative effects of vibration and temperature field during injection molding process was achieved. Using the equipment, the mechanical properties and morphology of samples prepared under different processing conditions were also be investigated in detail. Furthermore, self-reinforcement and self-toughness of IPP samples with good performance were achieved by optimizing the processing conditions. The results showed that the corporation of vibration and temperature field under certain processing conditions could induce the formation of plenty of βorm in IPP samples and improve the strength and toughness simultaneously. For example, the tensile strength was improved from 31.9MPa of static sample to 46.7MPa of vibration sample, and the corresponding loss modulus from 180MPa to 330MPa. The common skin-core structure of injection-molded IPP sample would be replaced by multi-layer structure under the effects of periodical shear induced by vibration field. Besides, the thickness and orientation degree of each layer also changed obviously. What's more, some specific crystal forms, such as single-fibril-core cylindrulite, multi-fibril-core cylindrulite, banded spherulite, were first discovered in the typical vibration-shear layer of vibration injection molded samples, which can enrich and perfect the crystallization and processing theories of IPP. The investigation results of vibration injection molded PP/MWCNT composites samples showed that the electrical conductive property was obviously improved, even one order-of-magnitude improvement. The mechanism of electrical conductivity of PP/MWCNT composites changed from a tunnel to an ohmic effect due to the achievement of perfect conducting paths in the samples. With the financial support, 28 papers have been published in domestic and foreign technical and scientific journals, including Carbon and Polymer. Among the articles, 14 papers were collected by SCI. Besides, two patents of invention were applied.

英文关键词： Vibration field;βorm; Self-reinforcement; Self-toughness; Temperature gradient