LDPE HDPE LLDPE的硅烷接枝反应

Silane Grafting Reactions of LDPE, HDPE and LLDPE

研究了DCP (过氧化异丙苯)为引发剂,A1 71 (乙烯基三甲氧基硅烷)与A1 51 (乙烯基三乙氧基硅烷)在LDPE (低密度聚乙烯) ,HDPE (高密度聚乙烯) ,LLDPE (线性低密度聚乙烯)上的接枝反应。A1 71接枝反应过程中,当过氧化物的加入量为0 .2 %时,活化能为正值。而当加入量为0 . 0 5%、0 . 1 %、0 . 1 5%、0 2 5%时,活化能为负值。尽管过氧化物在PE (聚乙烯)中交联反应程度的顺序为:LDPE >LLDPE >HDPE ,但A1 71接枝反应程度的顺序为LLDPE >LDPE >HDPE。与A1 71相比,A1 51在LDPE上具有较高的接枝反应速率,但它在水交联反应过程中,呈现出相对较低的反应速率。通过研究加入过氧化物量的变化对A1 71接枝反应热的影响,可知在过氧化物未达到一定量前(这个数值取决于所加入的硅烷的量) ,当过氧化物增加时,反应热是随之增加的。

With dicumyl peroxide (DCP) as initiator, the grafting reactions of vinyl trimethoxysilane A171 and vinyl triethoxysilane A151 with LDPE, HDPE and LLDPE were studied. The apparent activation energy of A171 grafting reactions was positive when the reactions were induced by 0.2 phr of peroxide. The apparent activation energies were negative when 0.05, 0.1, 0.15, and 0.25 phr of peroxide were used. The extents of A171 grafting reactions with PE were in the order of LLDPE>LDPE>HDPE, although the extents of peroxide crosslinking were in the order of LDPE>LLDPE>HDPE. As compared with A171, A151 produced a relatively high extent of grafting reactions with LDPE, but showed a relatively low rate of water crosslinkling reactions of the silane grafted LDPE. The study of the effects of the amount of peroxide on A171 grafting reaction heats demonstrated that the extent of silane grafting reactions increased proportionally as peroxide was increased until a certain amount (the value was dependent on the amuount of silane used).Beyond this amount of peroxde, the silane grafting did not increase, whereas the peroxide crosslinking appeared to increase significantly with the increase of the amounts of peroxide.