杜仲橡胶的环氧化改性研究

Epoxidized Modification of Eucommia Ulmoides Gum

采用溶液法对杜仲橡胶(EUG)进行环氧化改性,考察反应条件对环氧化反应的影响,采用红外光谱法、核磁共振氢谱法和差示扫描量热法等研究环氧度(E)对环氧化EUG(EEUG)熔融-结晶行为的影响。结果表明:随着反应温度升高和甲酸用量增大,E逐渐增大;反应温度为50℃,n(甲酸)︰n(碳-碳双键)︰n(双氧水)=0.8︰1︰1时,E较大,无明显的副反应;环氧化反应未改变橡胶分子链构型,EEUG的分子链仍然是反式-1,4结构;随着E增大,EEUG的结晶能力减弱,E为24.8%时EEUG完全失去结晶能力,宏观上由室温下的硬质塑料转变为弹性体。

In this study, eucommia ulmoides gum（EUG） was modif ied by epoxidation in solution. The effect of reaction conditions on the epoxidation reaction was investigated. The infl uence of epoxidation content（E） on the melting and crystallization characteristics of epoxidized eucommia ulmoides gum（EEUG） was studied using infrared spectroscopy, nuclear magnetic resonance spectroscopy and differential scanning calorimetry methods. The experimental results showed that, when the reaction temperature increased and the amount of formic acid increased, the epoxidation content of EEUG increased. When the reaction temperature was 50℃, the ratio of n（（ffoorrmmiicc acid）︰n（double bboonndd））︰n（hydrogen peroxide） was 00..88︰1︰1, the resulted epoxidation content of EEUG was high and there was no signif icant side reaction. It was found that the epoxidation reaction did not change the rubber molecular chain conformation, while the molecular chain of EEUG remained trans-1,4 structure. With the increase of epoxidation content, the crystallinity of EEUG decreased, and EEUG became an elastomer when the epoxidation content reached 24.8%.