沉淀法制备PVA/HA复合水凝胶的摩擦性能研究

Friction Properties of Poly(vinyl alcohol)/Hydroxylapatite Hydrogel Prepared by Compound in situ with Sol-gel Method

本文采用沉淀法制备了PVA/HA复合水凝胶,用光学显微镜表征PVA/HA复合水凝胶的微观形貌,采用平头圆柱压头测定PVA/HA复合水凝胶的压缩弹性模量并依据国标GB1685-82测量PVA/HA复合水凝胶的应力松弛特性,用精密位移传感器对PVA/HA复合水凝胶的接触变形特性进行测量,在UMT-II型微摩擦试验机上对PVA/HA复合水凝胶开展往复式摩擦试验,研究冷冻-解冻次数、接触时间及滑动速率对PVA/HA复合水凝胶的摩擦性能的影响.结果表明,沉淀法可在PVA水凝胶基体中合成得到粒度细、分散好的晶相HA微粒;PVA/HA复合水凝胶的弹性模量和应力松弛速率均随着冷冻-解冻次数的增加而增高;滑动过程中的法向位移和启动摩擦系数随接触时间的延长而增大,随冷冻-解冻次数的增加而减小;但启动摩擦系数与滑动速率无明显的相关联性.

The poly （vinyl alcohol）/hydroxyapatite composite hydrogel was prepared by compound in situ with solgel method. The microstructure of HA in composite hydrogel was observed using an Optics Microscope. The elastic modulus of compression and stress relaxation character of PVA/HA composite hydrogel were measured with the fiat cylindrical head. The contact deformation of PVA/HA composite hydrogel was measured with a high precision displacement sensor. The reciprocating sliding friction tests of PVA/HA composite hydrogel were performed on a micro-tribometer to study the influence of certain factors such as contact time, sliding speed and freezing-thawing cycles on start-up friction properties. Much fine HA particles with good scattered phase were synthesized in situ with sol-gel method. The elastic modulus and stress relaxation velocity of PVA/HA composite hydrogel increased with the increasing of freezing-thawing cycles. The normal displacement and start-up friction coefficient increased with the increasing of contact time and decreased with the increasing of freezing-thawing cycles. However, the start-up friction coefficient of PVA/HA composite hydrogel was independent on the sliding speed.