不同有机官能团聚硅氧烷微球的制备与表征

Preparation and characterization of polysilsesquioxane microspheres with different organofunctional groups

以乳液聚合法制备粒径分布均匀、球形度良好的聚甲基硅氧烷微球(MPSQ)、聚乙烯基硅氧烷微球(VPSQ)、聚巯丙基硅氧烷微球(MPPSQ),采用SEM、DLS、FT-IR、XRD、TGA、接触角等测试技术对微球的微观形貌、粒径大小及分布、聚集态结构、耐热性、疏水性等进行了表征。研究结果表明,有机基团对微球的耐热性与疏水性有重要影响,MPSQ和VPSQ的耐热性优于MPPSQ,疏水性从高到低依次为:MPSQ>VPSQ>MPPSQ。聚硅氧烷微球的形成过程可能是单体首先在催化剂的作用下,水解生成硅醇,硅醇开始缩聚形成核,之后通过吸取溶液的硅醇,不断成长,最终形成微球,其中同时存在核生成和核生长,两过程相互竞争,哪个过程占优势取决于反应条件。提高反应温度,使得核生成占优势,最终生成的微球粒径变小,单分散性变差。

Highly uniform and monodisperse methyl-functionalized polysilsesquioxane microspheres（MPSQ）、 vinyl-functionalized polysilsesquioxane microspheres（VPSQ） and thiol-functionalized polysilsesquioxane microspheres（MPPSQ） were prepared by emulsion polymeration.The morphology,size distribution,and state of aggregation were characterized by SEM,DLS,FT-IR,XRD.The thermodecomposition and hydrophobicity of these microspheres were investigated with TGA and water contact angle measurement.The results showed that the organofunctional groups played a key role in thermostability and hydrophobicity of microspheres,MPSQ and VPSQ possessed better thermostability than MPPSQ,the order of hydrophobicity was as following ： MPSQ 〉VPSQ〉MPPSQ.The formation mechanism of polysilsesquioxane microspheres may be explained by nucleation theory.First,the silanol groups came out when the precursor was catalyzed by triethylamine,then the polycondensation of silanol groups began and a large number of nuclei generated,and all the nuclei started to grow up by absorption of silanol groups in the solvent.Finally,monodisperse polysilsesquioxane microspheres formed.The nuclei generation process and nuclei growth process competed with each other during the reaction.The reaction condition determined the process which dominated the reaction.The particle would turn smaller and less monodisperse with increasing of the reaction temperature rises.