原位法制备环氧化天然橡胶及其表征

Preparation and characterization of epoxidized natural rubber by in-situ method

采用原位反应法使天然橡胶环氧化。研究了不同浓度的甲酸、双氧水、天然橡胶胶乳、温度对环氧化反应速率、环氧化度的影响。通过对红外、核磁图谱的分析得出可能发生的副反应机理,提出了减少副反应的处理方案。结果表明:当反应温度为20～30℃,当天然橡胶干胶含量为30%,pH值约为2.0,并且H2O2、HCOOH、天然橡胶(NR)的摩尔比为1∶0.55∶1时,反应进行稳定,同时能大大减少副反应的发生。只要按不同的时间安排取样就能得到环氧化度从10%到60%的环氧化天然橡胶。

The epoxidation of natural rubber by using in-situ method was described.This study contained the effects of formic acid,hydrogen peroxide,natural rubbers＇concentrations and reaction temperature on the reaction system.The product was characterized by FTIR and 1H-NMR.The results showed that when reaction temperature was 30℃,the dry rubber content was 30%,pH=2.0,the mole ratio of hydrogen peroxide,formic acid and natural rubber was 1∶0.55∶1,the epoxidation will occur without side reaction.A series of epoxy natural rubber with the degree of epoxy between 10%-60% were synthesized.