Du Jun-Wei, Zhou Tian-Tian, Zhang Rong, Hu Sheng-Fei
Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan 430068, China.
Polymers (Basel). 2023 Jul 24;15(14):3134. doi: 10.3390/polym15143134.
Ethylene-vinyl acetate copolymer (EVA) was added at different contents to the thermoplastic polyurethane (TPU) matrix to form a non-compatible blending system, and foaming materials with high pore density were prepared using the supercritical carbon dioxide extrusion method. The influence of the phase morphology and crystal morphology of the TPU/EVA blend on its foaming behavior was studied. The results show that EVA changed the phase morphology and crystal morphology of the blends, leading to the improved melt viscosity and crystallinity of the blend system. At the same time, interfacial nucleation increases the density of cells and decreases the cell thickness and size, which is beneficial for improving the foaming properties of the blends. For the EVA content of 10% (mass fraction), the cell size is small (105.29 μm) and the cell density is the highest (3.74 × 10 cells/cm). Based on the TPU/EVA phase morphology and crystal morphology, it is found that the sea-island structure of the blend has better foaming properties than the bicontinuous structure.
将不同含量的乙烯 - 醋酸乙烯酯共聚物（EVA）添加到热塑性聚氨酯（TPU）基体中，形成不相容共混体系，并采用超临界二氧化碳挤出法制备了具有高泡孔密度的发泡材料。研究了TPU/EVA共混物的相形态和晶体形态对其发泡行为的影响。结果表明，EVA改变了共混物的相形态和晶体形态，导致共混体系的熔体粘度和结晶度提高。同时，界面成核增加了泡孔密度，减小了泡孔厚度和尺寸，这有利于改善共混物的发泡性能。对于EVA含量为10%（质量分数）时，泡孔尺寸较小（105.29μm）且泡孔密度最高（3.74×10个泡孔/cm）。基于TPU/EVA的相形态和晶体形态，发现共混物的海岛结构比双连续结构具有更好的发泡性能。
