聚乙烯与马来酸酐反应的研究

Study on the Reaction of Polyethylene With Maleic Anhydride

聚乙烯(PE),170℃,在过氧化二异丙苯(DCP)存在下,以切割沸程为190—250℃煤油为溶剂用马来酸酐(MA)进行官能化反应。低分子量LDPE比高分子量LDPE更容易接枝。由于甲基的空间障碍,聚丙烯的接枝率大大小于聚乙烯。当加入空气时,由于PE的过氧化作用,促进了初期接枝速率的增加,但其后引入氮气又促使接枝率随时间增加而下降,这是由于POOMA分解而导致脱酐所致。更高的反应温度下,接枝率的再度增加则归因于MA对PE的热引发接枝。

Polyethylene (PE) is functionallized with maleic anhydride (MA) in presence of dicumyl peroxide at 170℃ in kerosene with a boiling range of 190-250℃ as solvent. Grafting is easier on low molecular weight LDPE than on higher molecular weight LDPE. Because of the steric hindrance of the methyl side groups, the rate of grafting on polypropylene is much lower than on polyethylene. The initial grafting velocity is increased on introduction of air into the reaction mixture, due to the peroxidation of the polyethylene. Introduction of nitrogen thereafter, however, renders the rate of grafting to decrease with time due to deanhydriding caused by decomposition of POOMA groups. Higher rate of grafting occurred at higher temperature is attributed to the thermally initiated grafting of MA on PE.