用溶液法环氧化改性反式-1,4-聚异戊二烯及产物表征

Epoxidation of trans-1,4-polyisoprene by solution method and characterization of products

以过氧乙酸为环氧化剂,在反式-1,4-聚异戊二烯(TPI)的氯仿溶液中进行环氧化反应,获得了具有不同环氧度的环氧化反式异戊橡胶(ETPI),用红外光谱和核磁共振氢谱对其进行了表征,并通过差示扫描量热分析研究了其热性能。结果表明,用溶液法能够合成出环氧度较高(最高可达80%)的ETPI,合适的反应温度为30℃;环氧化反应基本按化学计量进行,可通过调节过氧乙酸与TPI双键的摩尔比来控制环氧度。红外光谱和核磁共振氢谱的分析结果证实TPI经改性后已经在分子链上引入了环氧基团,两种方法测得ETPI的环氧度具有较好的线性关系。ETPI的环氧度超过38.0%后结晶完全被破坏,玻璃化转变温度则随其环氧度增加而升高,二者呈线性关系;环氧度不同的ETPI都只显示出1个玻璃化转变温度,说明在TPI分子主链上的环氧化改性是均匀的。

The epoxidized trans-1,4-polyisoprene（ETPI） with different epoxidation degree was synthesized with peracetic acid as oxidant in the chloroform solution of trans-1,4-polyisoprene（TPI）.Fourier transform-infrared spectroscopy（FTIR）,hydrogen nuclear magnetic resonance spectroscopy（1H-NMR） were used to measure the epoxidation degree of ETPI,and differential scanning calorimetry was used to analysis thermal performances.The results showed that the high epoxidation degree of ETPI（up to 80%） could be synthesized by solution method at the appropriate temperature of 30 ℃.The epoxidation degree could be controlled by regulating the mole ratio of peroxyacetic acid to the double bond of trans-1,4-polyisoprene owing to the fact that the epoxidation basically obeyed stoichiometric relationship.The results of FTIR and 1H-NMR confirmed that the epoxy group had been introduced in the molecular chain,and there was a good linear relationship between FTIR and 1H-NMR epoxidation degree measurement results.The crystallization of ETPI was all destroyed when the epoxidation degree exceeded 38%.The glass transition temperature increased with increasing epoxidation degree,and there was a good linear relationship between both.ETPI containing different epoxidation degree all had only one glass transition temperature,indicating the epoxidation modification of trans-1,4-polyisoprene was homogeneous.