橡胶聚合物在碳氢溶剂中的膨胀特性

Swelling Behavior of Rubber in the Hydrocarbon Liquids

为了验证碳氢有机溶剂在橡胶中的运输机理及运输特性,并为后期研究吸热型碳氢燃料与橡胶的相容性做准备,用浸泡/称量法对硫磺硫化体系(分别填充快压出炭黑和SiO2)、过氧化物硫化体系和混合硫化体系的天然橡胶在有机溶剂中的膨胀现象进行了研究。膨胀达到平衡时,快压出炭黑填充的硫磺硫化体系具有最小的溶剂吸收量,过氧化物硫化体系具有最大的溶剂吸收量。分别研究了交联密度、溶剂分子和温度对有机溶剂在橡胶中扩散的影响规律,并从热力学角度进行了详细分析。结果表明:实验所用橡胶-溶剂系统中,扩散结果偏离了Fick模型,为无规则扩散,且扩散系数随溶剂摩尔体积、相对分子质量、分子链的长度增加而减小;交联密度增加时溶剂的扩散减少,橡胶吸收溶剂的量减小;对二甲苯和丙苯比实验所用的烷烃有机溶剂更易使橡胶膨胀;在实验温度范围内,温度升高时橡胶的吸收量增加。

The swelling behavior of natural rubber was investigated using the immersion anct weighing technique to verify the transport mechanism and property of hydrocarbon solvent, which is ready for the study on the compatibility of endothermic hydrocarbon fuel and rubber. Natural rubber was vulcanized by sulfur vulcanization system which was filled with fast extruded furnace black and SiO2, peroxide curing system and a mixture consisting of sulfur and peroxide system. The sulfur vulcanization system filled with fast extruded furnace black showed the lowest solvent sorption and the peroxide curing system showed the highest. The influences of the crosslinking density, solvent molecule and temperature were studied, and the diffusion results were also analyzed using Fickian model. The results deviated from the Fickian model and the diffusion was anomalous in nature. Moreover, the diffusion coefficient increased when the molar volume, molecular weight and the length of molecular chain increased. Weight gain of the rubber and diffusion decreased with the erosslinking density increasing. It was found that p-xylene and propyl benzene could swell the rubber more easily than alkanes in the experiment. The diffusion and sorption of n-decane through sulfur vulcanization system filled with SiOz was studied in the temperature interval 18-60 ℃. It was found that the solvent sorption increased with the temperature.