聚氨酯丝与PET丝摩擦磨损性能的试验研究

Experimental Study on Tribological Behavior of Polyurethane Threads and PET Threads

在自制多功能粘着摩擦磨损性能试验台上进行仿壁虎刚毛用聚氨酯和聚对苯二甲酸乙二酯（PET）2种丝材的摩擦性能对比试验，在不同正压力下悬臂梁带动上试样丝以45°夹角相对下试样丝滑动，安装在悬臂梁上的二维传感器同时将正压力和摩擦力电信号输送计算机进行处理，计算得到摩擦系数平均值．结果表明：当法向压力处于0．5～2．0mN范围内时，聚氨酯丝的平均摩擦系数为4．22；当法向压力在0．2～1．0mN范围内时，PET丝的平均摩擦系数为0．29，前者为后者的14倍．高表面能引起的粘着为聚氯酯摩擦系数较高的主要原因．试验结果为仿壁虎机器人脚掌刚毛材料的选择与制备提供了依据．

Polyurethane threads and PET threads were selected to fabricate synthetic gecko setae for future wall-climbing robots. Tribological behavior of polyurethane threads and PET threads sliding against themselves, under condition of dry friction, was investigated and compared on a test rig for adhesion and friction. Under different normal forces, the upper specimen on a U-shaped clamp moved relatively to the lower specimen on a stationary frame at an angle of 45 degrees. The sensor of two dimensions simultaneously transmitted electric information of normal forces and friction into computer for calculating averaged friction coefficient. It was found that friction coefficient of polyurethane threads was 4.22 while normal forces varied from 0. 5 mN to 2 mN, which was 14 times larger than PET threads whose friction coefficient was 0. 29 while the normal forces ranged between 0.2 mN and 1 mN. It is the high surface energy that contributed to larger friction coefficient of polyurethane threads. Experimental results provide theoretical fundamental and slection basis for bio-mimic design of the feet of gecko robots.