新型含硅嵌段共聚物一步热解法制备多孔陶瓷的研究

Recently, preparation of porous ceramics by the one-step pyrolysis of hybrid block copolymers has received considerable attention as a new promising method, due to the advantages of facial processibility and flexible adjustment with porous structures. The reported work focused on the synthesis of various block copolymers, as well as preparation of porous ceramics by control the external factors of pyrolysis temperature, heating rate, and etc. However, to our best knowledge, the effect of molecular structures of block copolymers on the porous shape, size, order character and specific surface area has not been concerned. In this work, on the basis of synthesis of a series of silicon containing block copolymers and preparation of related porous ceramics by pyrolysis, the relationship between molecular structures, microphase separation of block copolymers and the porous structures of ceramics will be investigated. The results of the project are believed helpful for disclosing the relationship between molecular structures of block copolymers and the characteristics of porous ceramics, and providing guidance for further design of new block copolymer precusors to porous materials.

嵌段共聚物一步热解法是最近发展起来的一种新型的制备多孔陶瓷的方法，因具有操作简单、可灵活调控孔结构的优势而逐渐受到关注。但在已有工作中，研究重点多集中在合成各种嵌段聚合物，通过热解温度、升温速率等外在因素的控制，实现多孔陶瓷的制备，而对嵌段共聚物本身的结构特点对成孔形状、孔径、有序性、比表面积等方面的影响还缺少关注。本项目拟从分子结构设计出发，在合成一系列新型含硅嵌段共聚物并由其热解制备硅基多孔陶瓷的基础上，通过对聚合物分子结构、微相分离结构、陶瓷孔结构之间关系的系统研究，揭示嵌段共聚物一步热解制备多孔陶瓷方法中，聚合物分子结构与陶瓷孔结构特性的内在联系，为进一步设计合成新型嵌段共聚物，利用聚合物一步热解法制备新型多孔陶瓷材料提供依据。

设计合成了系列单官能、多官能的聚倍半硅氧烷（POSS），并通过硅氢加成反应合成了以POSS为核的共聚物，通过调节官能团比例，得到的共聚物状态可在粘稠状液体、蜡状物及高度交联固体粉末间进行调控；聚硼硅氮烷/N- 乙烯基吡咯烷酮（PSNB/NVP）体系自由基共聚制备了新型含硅杂化树脂，并由该杂化树脂制备了SiBCN多孔陶瓷。以自行设计合成的多官能聚硅氧烷(PSO)作为SiCO聚合物陶瓷前驱体，采用PMMA空心微球作为牺牲模板，制备了分布均匀的孔径为30-50微米左右的泡沫SiOC陶瓷。