低相对分子质量反式-1,4-聚丁二烯的环氧化改性

Epoxidized modification of low relative molecular mass trans-1,4-polybutadiene

采用以汽油为溶剂的预制过氧乙酸法和二甲苯为溶剂的过氧甲酸原位法,对低相对分子质量反式-1,4-聚丁二烯(LMTPB)进行了环氧化改性。通过核磁共振仪分析了环氧化LMTPB的结构,测定了环氧度,对化学滴定法测定的环氧度进行了修正。并研究了反应条件对环氧化LMTPB环氧度的影响。结果表明,LMTPB发生了环氧化反应,以环氧度为16·79%作为拐点,得到2个不同的线性回归校正方程。预制过氧乙酸法合成的环氧化LMTPB的环氧度较低,小于30%;过氧甲酸原位法合成的环氧化LMTPB的环氧度最高可达80%。温度和时间对环氧化反应的影响随着具体反应条件和反应体系的不同而不同,但LMTPB环氧化反应温度不宜超过45℃,反应时间不大于4h。环氧化LMTPB的环氧度随溶剂极性的增加而增加。

Epoxidized low relative molecular mass trans-1,4-polybutadiene （ LMTPB ） was synthesized by both reaction methods of pre-prepared peroxide acetic acid with gasoline solvent and peroxide formic acid in-situ with xylene solvent. The structure and degree of epoxidation of epoxidized LMTPB were measured with nuclear magnetic resonance （ ^1H-NMR）. The degree of epoxidation measured by titrimetric method was revised that measured by the ^1H-NMR. The effects of reaction conditions on degree of epoxidation of epoxidized LMTPB were studied. The results showed that epoxidation of LMTPB was carried out, and two different linear equation were got with degree of epoxidation 16.79% as inflexion point. The method of pre-prepared peroxide acetic acid could make degree of epoxidation less than 30%, but degree of epoxidation obtained by peroxide formic acid in-situ was nearly 80%. The effects of reaction temperature and time on epoxidation of LMTPB were different in reaction conditions and reaction systems. The reaction temperature should not be more than 45℃ and reaction time should not be more than 4 h. The degree of epoxidation of epoxidized LMTPB increased with increasing of solvent polarity.