用固相反应法制备硅烷化改性天然橡胶及其力学性能

摘要

The natural rubber (NR) was chemi-cally modified using triethylchlorosilane (Et3SiCl) with sodium hydride (NaH) as activator in Haake torque rheometer by solid phase method was pre-pared under the conditions of reaction temperature 90 -93℃,total reaction time 30 min. The silaniza-tion modified natural rubber (Si-NR) was characte-rized by Fourier transform infrared spectroscopy and gel permeation chromatography, the vulcanization characteristics, crosslinking density, mechanical and dynamic mechanical properties and heat aging properties of Si-NR were investigated. The results showed that the organic silicone group —SiEt3was introduced into the NR molecular chain through the modification. No significant chain scission, crosslinking and other side reactions occurred in the rubber macromolecule. Compared with NR, the Payne effect of the material was obviously reduced, the tensile strength and the modulus at 300% were increased,the dynamic compression fatigue tempera-ture and the compression permanent set were signifi-cantly reduced, and the aging resistance were en-hanced.%以氢化钠(NaH)为活化剂,采用固相法在Haake转矩流变仪中使用三乙基氯硅烷(Et3SiCl)对天然橡胶(NR)进行化学改性,在反应温度90~93 ℃、总反应时间30 min条件下制得硅烷化改性天然橡胶(Si-NR).用傅里叶变换红外光谱和凝胶渗透色谱对Si-NR进行了表征,并研究了Si-NR的硫化特性、交联密度、力学及动态力学性能和耐热空气老化性能.结果表明,通过改性在NR分子链上引入了有机硅基团—SiEt3,该过程中橡胶大分子未发生明显的断链、交联等副反应;与NR相比,Si-NR胶料的Payne效应明显降低,拉伸强度和300%定伸应力均增大,动态压缩疲劳温升和压缩永久变形都明显降低,耐老化性能增强.