不同界面条件下TPU/HVSSBR复合材料摩擦性能及机理分析

热塑性聚氨酯(TPU)因具有耐磨、耐水解、抗撕裂和抗弯曲等特点已成为热门材料被广泛使用，而其作为鞋底材料最突出的问题是止滑性能不足. 本研究中将高乙烯基溶聚丁苯橡胶(HVSSBR)与TPU进行橡塑共混来改善TPU材料的止滑性能. 采用LAT-100试验机测试了恒定面压下不同共混比的TPU/HVSSBR复合材料干、湿摩擦表面以及不同冰面温度(−20、−10和−5 ℃)下摩擦系数的变化. 结果表明：HVSSBR相的掺入同时提高了TPU的干摩擦系数fD、湿摩擦系数fW以及冰面摩擦系数fI，其中HVSSBR质量分数为40%的TPU复合材料相较于TPU，fD提高了35%，fW提高了13%，不同冰面温度(−20、−10和−5 ℃)下fI分别提高了59%、89%和116%；结合摩擦学理论，通过将fD、fW、fI与硬度H以及损耗因子tanδ等参数拟合的方法来分析材料在不同界面条件下的摩擦机理，结果发现fD、fW、fI与tanδ/H呈线性正相关，相关性大小为湿摩擦>冰面摩擦>干摩擦，表明了湿摩擦和冰面摩擦机理符合黏附摩擦模型，干摩擦为黏附摩擦和滞后摩擦共同作用的结果.

Thermoplastic polyurethane (TPU) has become a popular and widely used material owing to its outstanding properties including wear resistance, hydrolysis resistance, tear resistance and bending resistance. However, its most prominent shortcoming when applied as shoe sole material is insufficient anti-slip performance. In this study, high vinyl content solution polymerized styrene-butadiene rubber (HVSSBR) was blended with TPU via rubber-plastic blending to improve the anti-slip performance of TPU materials. The LAT-100 testing machine was utilized to test the changes in coefficient of friction (COF) of TPU/HVSSBR composites with different blending ratios under constant normal pressure on dry and wet friction surfaces, as well as at different ice surface temperatures (−20, −10, and −5 ℃). The results demonstrate that the incorporation of HVSSBR phase simultaneously elevates the dry friction coefficient fD, wet friction coefficient fW and ice friction coefficient fI of TPU. Specifically, compared with neat TPU, the TPU composite with 40% mass fraction of HVSSBR exhibits a 35% increase in fD, 13% increase in fW, and 59%, 89% and 116% increases in fI at −20, −10 and −5 ℃, respectively. Combined with tribological theory, the friction mechanisms of the materials under various interface conditions were analyzed by fitting fD, fW, fI with parameters such as hardness H and loss factor tanδ. It is found that fD, fW and fI show a linear positive correlation with tanδ/H, and the correlation strength follows the order: wet friction > ice friction > dry friction. This indicates that the friction mechanisms of wet and ice friction conform to the adhesive friction model, while dry friction is the result of the combined action of adhesive friction and hysteresis friction.