The production of soft thermoplastic polyurethane (TPU) foam typically faces challenges such as low production efficiency and inherent shrinkage characteristics. In addressing these issues, this study combines the pressure swing strategy with a N₂/CO₂ mixed foaming strategy, and based on the mixed gas state equation and cubic antishrinkage model, this study systematically investigates their influence on the production process of TPU foam. The results indicate that the pressure swing strategy significantly reduces the saturation time and achieves a TPU foam with a multimodal cell structure. By adjusting parameters such as the CO₂/N₂ ratio and residual pressure, the pressure swing strategy can flexibly regulate the cell size (20.41–312.42 μm) and expansion ratio (2.59–7.17). Compared to TPU foam with a uniform cell structure, TPU foam with a multimodal cell structure exhibits superior resilience (energy loss coefficient of ∼21% and compression modulus of ∼0.63 MPa) and fatigue resistance (maximum stress of ∼0.21 MPa and compression strength of ∼0.02 MPa). This work is of significant importance for enhancing the performance of elastomeric foams and improving the efficiency of the production process.

中文翻译：

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基于变压策略制备的多峰泡孔结构微孔热塑性聚氨酯（TPU）及其压缩力学性能

软质热塑性聚氨酯 (TPU) 泡沫的生产通常面临生产效率低和固有收缩特性等挑战。针对这些问题，本研究将变压策略与N ₂ /CO ₂混合发泡策略相结合，基于混合气体状态方程和立方抗收缩模型，系统研究了它们对TPU泡沫生产过程的影响。结果表明，变压策略显着缩短了饱和时间，并获得了具有多峰泡孔结构的 TPU 泡沫。通过调节CO ₂ /N ₂比和残余压力等参数，变压策略可以灵活调节泡孔尺寸（20.41-312.42 μm）和膨胀比（2.59-7.17）。与具有均匀泡孔结构的 TPU 泡沫相比，具有多峰泡孔结构的 TPU 泡沫表现出优异的回弹性（能量损失系数约为 21%，压缩模量约为 0.63 MPa）和抗疲劳性（最大应力约为 0.21 MPa，压缩强度约为〜0.02 兆帕）。这项工作对于增强弹性泡沫的性能和提高生产过程的效率具有重要意义。