原位聚合物微纤网络抑制聚丙烯注塑制品皮芯结构的研究

聚丙烯注塑制品在汽车、家用电器等领域应用广泛，但由于注塑中流动场和温度场不均匀，通常注塑聚丙烯制品呈皮芯结构，引起内应力开裂、翘曲、尺寸不均匀等问题，到目前为止，还没有一种有效抑制注塑制品皮芯结构的方法。本课题在前期研究的基础上，提出利用聚合物微纤网络均分流动场和结晶成核缩短冷却时间，并在保压过程中施加振动流动场抑制聚丙烯注塑制品皮芯结构的思路。本课题拟进一步研究流动场下聚合物微纤网络的形态演变和聚丙烯的结晶行为及形态，随后，采用工程方法研究实际加工流动场下聚合物微纤网络形态演变规律和注塑制品皮芯结构特点，达到深入认识其抑制机理和调控注塑制品皮芯结构的目的，为聚丙烯注塑制品形态结构设计和高性能化提供指导。

Polypropylene has gained popularity in automobile and household appliances, etc. However, due to the intrinsic inhomogeneity of shear flow field and temperature field during the injection molding, the parts always exhibit skin-core structures, which inevitably induce the stress cracking、warping、uneven size. Up till now, how to effective suppression the skin-core structure has not been founded. Based on previous groundwork, the skin-core structure is expected to be suppressed by using a combination of microfibrill and the continuous oscillatory shear at the packing stage. On one hand, microfibrill can homogenize the shear field and shorten the nucleating time. On the other hand, the continuous oscillatory shear further fascinates suppression of skin-core structure. We would like to examine the evolution of the microfibrillar morphology and the crystallization behavior of polypropylene under a shear flow, furthermore, understand the crystallization behavior polypropylene containing microfibrill and the characteristic of the skin-core structure in factual molding processing. Thus, some insights of the mechanism about how the microfibrill suppresses the skin-core structure of polypropylene can be obtained, which could be used to manipulate the skin-core structure of polypropylene and provide some guideline to get the high performance parts of polypropylene.