Tissue engineering scaffolds should provide a suitable porous structure and proper mechanical strength, which is beneficial for the delivery of growth factor and regulation of cells. In this study, the open‐porous polycaprolactone (PCL)/poly (lactic acid) (PLA) tissue engineering scaffolds with suitable porous scale were fabricated using different ratios of PCL/PLA blends. At the same time, the relationship of foaming process, morphology, and mechanical behavior in the optimized batch microcellular foaming process were studied based on the single‐factor experiment method. The porous structures and mechanical strength of the scaffolds were optimized by adjusting foaming parameters, including the temperature, pressure, and CO2 dissolution time. The results indicated that the foaming parameters influence the cell morphology, further determine the mechanical behavior of PCL/PLA blends. When the PCL content is high, with the increase of temperature and time, the cell diameter and the elastic modulus increased, and the tensile strength and elastic modulus increased with the increase of the average cell size, and decreased as the increase of the cell density. While when the PLA content was high, the cell diameter showed the same trend, and the tensile strength and elastic modulus were higher, and the elongation at break was lower, and tensile strength and elastic modulus decreased with the increase of the average cell size and increased with the increase of cell density. This work successfully fabricated optimized porous PCL/PLA scaffolds with excellent suitable mechanical properties, pore sizes, and high interconnectivity, indicating the effectiveness of modulating the batch foaming process parameters.

Isotactic polypropylene micro parts were molded at different injection speeds by microinjection molding. The morphology and micro structure were characterized by a polarizing microscope, and the mechanical properties of differently structured layers were characterized by nanoindentation experiments. The influence of injection speed on the nanoindentation mechanical properties of each structural layer of the micro parts was analyzed. The results showed that the mechanical properties of different layers were different, the modulus and hardness of the position near the core layer were largest, and the modulus and hardness of the position near the skin were smallest. It is compelling that the modulus and hardness of each layer decreased first and then increased as the injection speed increased under a higher melt temperature (240 °C). Meanwhile, the opposite trend was observed at a lower melt temperature (220 °C). This phenomenon can be attributed to the competitive mechanism of the shear heat effect and the disorientation effect. In addition, injection speed had a greater influence on the nanoindentation mechanical properties in the perpendicular direction than in the flow direction. This work systematically explored the relationship between the microstructure and the local mechanical properties, which can provide new insights for microinjection molding design in the future. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47329.