This study introduces a method to investigate the relationship between the multi-level microstructures and mechanical properties of polymer blends prepared by micro-injection molding (µIM). Special morphological features were systematically researched. Polycarbonate (PC), poly(ethylene terephthalate) (PET), and PC/PET microparts all exhibit typical “skin-core” morphologies. The thickness of the core layer is much greater than that of the skin layer, and the thickness of the skin layer gradually decreases along the flow direction. Photoacoustic Fourier transform infrared spectroscopy records reveal that the PC molecular chain has the biggest orientation degree, followed by PC/PET and PET chains under the same µIM processing conditions. Moreover, the molecular chains orientation in the skin layer is more than 50% that in the core layer. Nanoindentation tests are conducted to study local mechanical properties. The higher modulus in the shear layer is affected to a greater extent by high shear action in comparison with the frozen and core layers. Uniaxial tensile testing demonstrates that the tensile strength of PC/PET micropart is 15.5% higher than that of the PET micropart, while the toughness is 16% higher than that of the PC microparts. In-situ, high- speed tensile imaging, combined with scanning electron microscopy micrographs of the fracture section, are used to study the fracture behaviors of the microparts. The results gathered in this paper may provide a theoretical basis and data to support the feasibility and efficiency of micro-injection molded polymer blends.

这项研究介绍了一种方法，以研究通过微注射成型（µIM）制备的聚合物共混物的多级微观结构与力学性能之间的关系。系统地研究了特殊的形态特征。聚碳酸酯（PC），聚对苯二甲酸乙二酯（PET）和PC / PET微粒均显示出典型的“皮芯”形态。芯层的厚度远大于表层的厚度，并且表层的厚度沿流动方向逐渐减小。光声傅里叶变换红外光谱记录表明，在相同的µIM处理条件下，PC分子链的取向度最大，其次是PC / PET和PET链。而且，表皮层中的分子链取向大于芯层中的分子链取向的50％。进行纳米压痕测试以研究局部机械性能。与冷冻层和芯层相比，剪切层中较高的模量受到较高剪切作用的影响更大。单轴拉伸试验表明，PC / PET微型零件的拉伸强度比PET微型零件的拉伸强度高15.5％，而韧性比PC微型零件的拉伸强度高16％。原位高速拉伸成像结合断裂截面的扫描电子显微镜显微照片，用于研究微零件的断裂行为。本文收集的结果可提供理论基础和数据，以支持微注射成型聚合物共混物的可行性和效率。与冷冻层和芯层相比，剪切层中较高的模量受到较高剪切作用的影响更大。单轴拉伸试验表明，PC / PET微型零件的拉伸强度比PET微型零件的拉伸强度高15.5％，而韧性比PC微型零件的拉伸强度高16％。原位高速拉伸成像结合断裂截面的扫描电子显微镜显微照片，用于研究微零件的断裂行为。本文收集的结果可提供理论基础和数据，以支持微注射成型聚合物共混物的可行性和效率。与冷冻层和芯层相比，剪切层中较高的模量受到较高剪切作用的影响更大。单轴拉伸试验表明，PC / PET微型零件的拉伸强度比PET微型零件的拉伸强度高15.5％，而韧性比PC微型零件的拉伸强度高16％。原位高速拉伸成像结合断裂截面的扫描电子显微镜显微照片，用于研究微零件的断裂行为。本文收集的结果可提供理论依据和数据，以支持微注射成型聚合物共混物的可行性和效率。比PET微零件高5％，而韧性比PC微零件高16％。原位高速拉伸成像结合断裂截面的扫描电子显微镜显微照片，用于研究微零件的断裂行为。本文收集的结果可提供理论依据和数据，以支持微注射成型聚合物共混物的可行性和效率。比PET微零件高5％，而韧性比PC微零件高16％。原位高速拉伸成像结合断裂截面的扫描电子显微镜显微照片，用于研究微零件的断裂行为。本文收集的结果可提供理论依据和数据，以支持微注射成型聚合物共混物的可行性和效率。