发泡三元乙丙橡胶在湿热盐雾老化环境下的力学性能研究

Study on the mechanical properties of foamed EPDM in aging tests of humid hot and salt-fog environment

为评价发泡三元乙丙橡胶在高温高湿高盐雾环境下的服役情况,对材料进行海南万宁地区自然老化以及试验室加速老化(热空气、湿热、盐雾)试验。系统研究材料的交联密度、拉伸强度、断裂伸长率、压缩永久变形率等物理机械性能的变化规律。结果表明,相对于拉伸强度,压缩永久变形及断裂伸长率对环境影响具有更高的敏感性;在相同温度下,高湿度情况下材料压缩永久变形率增大,拉伸强度增大;高湿度可以减小老化时温度对材料的拉伸强度跟断裂伸长率的影响;盐雾环境几乎对拉伸强度跟断裂伸长率不产生影响。可以将压缩永久变形作为发泡三元乙丙橡胶材料及制品在湿热盐雾环境下使役寿命评价的主要指标。

In view of the high temperature,high humidity and high salt-fog environment in South Seas of China,the natural aging and the laboratory accelerated aging tests(hot air,humid heat and salt-fog)of the foamed EPDM were carried out in Wanning area of Hainan Province.The chemical structure and physical properties of the foamed EPDM were analyzed by crosslinking density,tensile strength,elongation at break and permanent set.The results show that the permanent set and elongation at break are more sensitive to the environment than the tensile strength;At the same temperature,the permanent set and the tensile strength increases with high humidity compared with low humidity;High humidity can reduce the influence of aging temperature on the tensile strength and elongation at break;In the salt-fog environment aging test,there were substantially unchanged of the tensile strength and elongation at break;Permanent set of the foamed EPDM materials and products can be used as the main index to evaluate the service life in heat humidity and salt-fog environment.