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目的：提高纳米SiO2在有机溶剂及树脂基体中的分散性。方法首先利用普通自由基聚合的方式制备苯乙烯及马来酸酐共聚物( PSMA),再与丙炔醇反应,在分子链上引入多个炔基,然后利用硅烷偶联剂KH560改性纳米SiO2,之后与叠氮化钠反应,在纳米SiO2粒子表面引入多个叠氮基团,最后将带有多个炔基的分子链通过“点击”化学接枝到纳米SiO2表面。结果酸碱反滴定法测得聚合物中马来酸酐的质量分数为26.5%。凝胶渗透色谱测得聚合物数均相对分子质量为36200,相对分子质量分布为1.39。红外表征显示,聚合物上带有多个炔基,纳米SiO2粒子表面带有多个叠氮基,经过24 h“点击”化学反应,聚合物成功接枝到粒子表面,同时叠氮基吸收峰消失。热重( TG)结果表明,接枝率为32.83%。扫描电镜分析表明,接枝聚合物后,粒子的分散性增强。结论分子链上含有多个炔基的共聚物( PSMA)通过“点击”化学反应成功接枝到了纳米SiO2粒子表面,不会引起粒子间的交联,可以明显提高纳米SiO2粒子在有机溶剂中的分散性。

ABSTRACT:Objective To improve the dispersion of nano-silica in organic solvents and resin matrix. Methods Firstly, styrene-maleic anhydride copolymer ( PSMA) was synthesized by common free radical polymerization. Then, the copolymer was reacted with propargyl alcohol to introduce multiple alkynyl groups. Nano-silica was firstly modified by silane coupling agent ( KH560 ) , then reacted with sodium azide to introduce azide groups. Finally, the copolymer ( PSMA) with multiple alkynyl was grafted onto the surface of nano-silica via ‘click’ chemistry. Results The mass fraction of maleic anhydride in polymer was 26. 5% measured by neutralization titration. The number average molecular weight of the polymer was 36200 and the molecular weight distribution was 1. 39 analyzed by gel permeation chromatography. Analysis by IR ( FT-IR) indicated that there were multiple alkynyl on the copolymer, and multiple azide on the surface of nano-silica. After‘click’ chemical reaction for 24 hours, the copolymer was graf-ted onto nano-silica with disappearance of characteristic absorption peaks of azide groups. Analysis of SEM and TG conformed that 32. 83% copolymer (PSMA) was grafted onto nano-silica, and scanning electron microscopy showed the dispersion was improved after the graft. Conclusion Copolymer ( PSMA) with multiple active alkynyl groups can be grafted onto nano-silica via‘click’ chemistry successfully with no occurrence of particle cross-linking, and the dispersion of nano-silica in organic solvents was improved obviously.