二氧化硅粒子的表面化学修饰--方法、原理及应用

Chemical Modification of Silica: Method,Mechanism,and Application

本文综述了近年来国内外对二氧化硅粒子表面化学修饰的研究成果,主要介绍了偶联剂法、表面接枝法和一步法的反应原理,探讨了各种改性方法的关键问题和优势,重点介绍了表面接枝法,包括以普通自由基聚合、原子转移自由基聚合和可逆加成-断裂链转移自由基聚合为原理的表面聚合生长接枝法和以开环加成、点击化学和酯化反应为原理的偶联接枝法。由于表面接枝法一般需要偶联剂在二氧化硅表面引入官能团,本文亦简要介绍了硅烷偶联剂及其修饰机理和一步法的反应原理。表面修饰的基团或接枝的聚合物赋予二氧化硅粒子新的性能;经表面修饰的二氧化硅粒子,提高了在有机溶剂或有机基体中的分散性,增加了与有机基体的界面相容性,并已广泛应用于新材料的合成。

Silica is one of the most important inorganic materials, and has been drawing a growing number of attentions in the field of organic/inorganic composite materials. In this paper, research progress on methods and mechanisms of chemical modification as well as applications of modified silica particles are reviewed in detail. Mechanisms of coupling method, surface grafting methods （ ＂grafting from＂ and ＂grafting onto＂ included） and one- step method are discussed along with the comments on key points and advantages of these methods. The methods of ＂grafting from＂ based on conventional free radical polymerization, atom transfer radical polymerization and reversible addition-fragmentation chain transfer polymerization are discussed, whereas ＂grafting on＂ based on ring- opening addition reaction, ＂click chemistry＂ and esterification reaction are described. Generally, endowing silica surface with functional groups for further reaction by silane coupling agents is essential, and silane coupling agents and their modification mechanisms are introduced firstly. In addition, one-step method is also discussed here. At the same time, significances of surface modification which are improvement on dispersibility, endowing silica with functionality and improvement on compatibility are summarized. The dispersibility of surface modified silica particles in organic solvents or organic matrix is improved. The modified silica particles are functioned by the groups or polymers which are grafted on their surfaces. The adhesive forces between organic phase and inorganic phase are enhanced since the modified silica particles are dispersed well in the organic matrix. And the modified silica particles are expected applications in fabricating new materials.