注塑成型的结晶高分子材料在使用过程中经常受到外力的作用，因此其断裂机理的研究具有重要的实际应用价值。本项目拟利用同步辐射广角、小角和超小角X射线散射技术在线研究微注塑成型的等规聚丙烯及其高抗冲合金在力学破坏过程中的多尺度结构演化规律。通过控制微注塑加工成型条件制备片晶厚度、分子链取向程度、晶型分布、分散相尺寸和形态等结构参数明确的样品，然后应用超小角X射线散射方法构建一个关于塑性形变和空洞化的多维相图，进而分别阐明不同力学破坏模式的微观结构参数依赖性，从而揭示高分子材料宏观力学断裂的微观机理，力图建立有利于提升材料服役时间的结构模型，为正确设计、合成和加工高分子材料提供理论指导和科学依据。

Injection molded crystalline polymer materials are often subjected to external forces in the course of utilization, and hence the study of their fracture mechanism is of great value in practical application. The purpose of the present project is to in situ study the multi-scale structural evolution of micromolded isotactic polypropylene and its high impact alloys in the process of mechanical failure using synchrotron wide, small, and ultra-small angle X-ray scattering techniques. The samples with explicit structural parameters including lamellar thickness, degree of orientation of molecular chains, crystalline modification distribution, as well as dispersed phase dimension and morphology will be precisely fabricated by controlling micromolding conditions. Afterwards, a multi-dimensional phase diagram concerning plastic deformation and cavitation is to be constructed via ultra-small angle X-ray scattering technique, and further the dependence of different mechanical failure mode on the microstructural parameters is to be elucidated. Therefore, the microscopic mechanism of macroscopic mechanical fracture being active in polymer materials will be revealed, and a structural model will be established for the enhancement of service lifetime in polymer materials, thus setting the theoretical guidance and scientific basis for the correct design, synthesis, and processing of polymer materials.