苯乙烯-异戊二烯-苯乙烯三嵌段共聚物的环氧化

Epoxidation of styrene-isoprene-styrene triblock copolymer

以甲酸和过氧化氢反应生成的过氧甲酸为氧化剂、聚乙二醇(PEG-400)为相转移催化剂,对苯乙烯-异戊二烯-苯乙烯三嵌段共聚物(SIS)进行了环氧化,考察了SIS的环氧化反应影响因素,并探讨了环氧化反应机理。结果表明,在C=C/甲酸/过氧化氢(摩尔比)为1/2/6、反应时间为2 h、反应温度为50℃、SIS质量分数为20%时,SIS的环氧化效果最好,环氧度可达到39. 2%;加入相转移催化剂PEG-400可以大幅度提高环氧度,当PEG-400/SIS(质量比)为1. 0时,环氧度可达到59. 5%; SIS的环氧化反应主要发生在聚异戊二烯链节中1,4-结构的双键上,且反应活性由强到弱依次为顺式-1,4-结构、反式-1,4-结构、3,4-结构。

Styrene-isoprene-styrene triblock copolymer （SIS） were epoxidized with peroxyformic acid generated from formic acid and hydrogen peroxide with PEG-400 as a phase transfer catalyst. The effect factors of epoxidation were investigated, and the epoxidation mechanism was studied. The results showed that when C = C/HCOOH/H202 （mole ratio） was 1/2/6, reaction time was 2 h, reaction temperature was 50℃ and mass fraction of SIS was 20% , the epoxy reaction of SIS the epoxy degree could reach 39 was carried out 2%. However, and epoxy degree was greatly improved to 59.5% when phase transfer catalyst PEG-400/SIS （mass ratio） was 1.0/100. The epoxidation mainly occured at the 1,4-double bonds in the polyisoprene block, and the order of the reaction activity from strong to weak was cis-1,4-structure, trans-1 4-structure and 3,4-structure.