Cationic Graft Polymerization from Ultrafine Silica Initiated by Acylium Perchlorate Groups Introduced onto the Surface
Cationic Graft Polymerization from Ultrafine Silica Initiated by Acylium Perchlorate Groups Introduced onto the Surface
复制标题
表面引入高氯酸酰基引发超细二氧化硅的阳离子接枝聚合
DOI：
10.1295/polymj.25.83
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发表时间：
1993
期刊：
影响因子：
2.8
通讯作者：
Akira Kogure
中科院分区：
文献类型：
--
作者：
N. Tsubokawa;Akira Kogure
通过高氯酸银与酰氯基团的反应，将酰基高氯酸基团引入超细二氧化硅上，酰氯基团是通过用亚硫酰氯处理羧基而引入的。通过用4-三甲氧基甲硅烷基四氢邻苯二甲酸酐处理二氧化硅而引入的酸酐基团的水解实现了在二氧化硅表面上引入羧基。引入到二氧化硅上的表面酰基高氯酸盐基团能够引发苯乙烯的阳离子聚合，并且聚苯乙烯有效地接枝到表面上。嫁接率提高到65.4%。接枝效率在前几次转化期间较高，但随着转化率的增加而迅速下降。这表明接枝聚合物从酰基高氯酸盐基团生长，并且未接枝聚合物是通过生长的聚合物阳离子链转移到单体而逐渐形成的。四氢呋喃、氧化苯乙烯、β-丙内酯和ε-己内酯的阳离子开环聚合也由二氧化硅表面的高氯酸酰基引发，得到相应的聚合物接枝二氧化硅。聚合物接枝二氧化硅在接枝聚合物的良好溶剂中提供稳定的胶态分散体。
The introduction of acylium perchlorate groups onto ultrafine silica was achieved by the reaction of silver perchlorate with acyl chloride groups, which were introduced by the treatment of carboxyl groups with thionyl chloride. The introduction of carboxyl groups onto silica surface was achieved by the hydrolysis of acid anhydride groups which introduced by the treatment of silica with 4-trimethoxysilyl tetrahydrophthalic anhydride. Surface acylium perchlorate groups introudced onto silica were capable of initiating cationic polymerization of styrene and polystyrene was effectively grafted onto the surface. The percentage of grafting increased to 65.4%. The grafting efficiency was high during the first few conversion but rapidly decreased with an increase in conversion. This suggests that the grafted polymer propagates from acylium perchlorate groups and that ungrafted polymer is gradually formed by a chain transfer of growing polymer cation to the monomer. The cationic ring-opening polymerizations of tetrahydrofuran, styrene oxide, β-propiolactone, and ε-caprolactone were also initiated by acylium perchlorate groups on silica surface to give the corresponding polymer-grafted silica. The polymer-grafted silica gave a stable colloidal dispersion in good solvents for grafted polymer.