甲基乙烯基硅橡胶的化学交联及溶胶与凝胶分布的研究

STUDY ON CHEMICAL CROSSLINKING OF METHYL VINYL SILICONE RUBBER AND THE DISTRIBUTION OF GEL AND SOL

研究了二甲基及乙烯基含量不同的甲基乙烯基硅橡胶的化学法交联的凝胶生成动力学及凝胶溶胶分配关系。在化学法交联过程中,溶胶平均分子量及单位交联剂量的交联度均是交联剂量的减函数。从溶胶与凝胶分配关系可知,二甲基硅橡胶的交联为无规过程,ln((1-S)/S]～Ⅰβ为线性关系,而甲基乙烯基硅橡胶的交联不能以无规过程来描述,ln[(1-S)/S]～Ⅰβ为非线性关系。

In this paper, the kinetics of gel formation and the distribution of gel and sol for dimethyl silieone rubber (DMSR) and methyl vinyl silicone rubber (MVSR) with different vinyl content were investigated in the process of crosslinking with chemical method. The sol molecular weight and the degree of crosslinking per unit crosslinking agent are all reduced function of crosslinking agent. From the equation of the distribution of gel and sol, it maybe known that In1-s/s vs IB is linear relationship for DMSR, but as for MVSR the linearrelationship between ln 1-x/s and IB can not be established. Therefore, these conclusion haveexplained that the process of cross linking of DMSR is random, but can not be described by random process for MVSR.The crosslinking efficiency f of MVSR with different vinyl content in the process of chemical crosslinking can be calculated by following equationf=fA [XA+(1-XA)C]where fA(0.068)is crosslinking efficiency for DMSR; XA is mole fraction of seg-ment;C= is the degree of crosslinking per unit crosslinking agent of divinyl siliconerubber (DVSR) ; q0A is the degree of crosslinking per unit crosslinking agent of DMSR.The calculated results may be shown by following listVinyl content (%) . 0 0.1 0.2 0.435 From f value in list, it can be seen that inter-enhancement effect of vinyl group is exhibited more obviously in the process of chemical crosslinking.