摘要
模板法是制备无机中空微球的重要方法之一.首先通过苯乙烯和甲基丙烯酸的无皂乳液聚合法制得表面含羧基、粒径为360nm的单分散聚苯乙烯(PSt)乳胶粒,并以此为模板,分别采用表面改性-前驱体水解法(PHC)和SiO2纳米颗粒层层自组装法(LBL),制备出了不同壳层厚度的PSt/SiO2核壳结构复合微球,然后经500℃煅烧4h,得到SiO2中空微球.利用透射电镜和扫描电镜对微球结构形态进行了表征.研究表明,首先利用γ-氨丙基三乙氧基硅烷(KH-550)对PSt模板微球进行表面改性、然后再在乙醇-水混合介质中进行原硅酸乙酯(TEOS)水解与缩合反应的PHC法,是制备PSt/SiO2核壳结构复合微球的简便方法,复合微球经煅烧可制得表面均匀、结构致密、壳层厚度和形貌可控的SiO2中空微球;而LBL法制备PSt/SiO2核壳结构复合微球的工艺复杂,煅烧后所得SiO2中空微球结构疏松,易于破碎.
Template process is of importance in the preparation of voided inorganic microspheres. In this paper, monodispersed polystyrene （PSt） template particles with diameter of 360 nm and surface carboxyl groups was first synthesized via batch soap-free emulsion copolymerization of styrene and methacrylic acid, and the core-shell PSt/SiO2 composite microspheres with variable shell thickness were prepared by surface modification-precursor method （PHC） and layer by layer method （LBL）, respectively, and the voided SiO2 microspheres were finally obtained by calcining the PSt/SiO2 composite microspheres at 500 ℃ for 4 h. The morphology of the microspheres was characterized on transmission electron microscopy （TEM） and scanning electron microscope （SEM）. In the PHC method, when the PSt template particles were first modified with γ-aminopropyl triethoxysilane （KH-550） followed by reaction with tetraethoxysilane （TEOS） in the mixture medium of ethanol and water, the voided SiO2 microspheres with controllable uniformly compact shell thickness and smooth surface were received by calcining. However, the voided SiO2 microspheres resulted from LBL method were easy broken up because of their incompact shell structure, and their surface was much rough. In comparison, PHC method was much easier and more suitable than LBL method in the manufacture of voided SiO2 microspheres via template process.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2010年第19期2000-2006,共7页
Acta Chimica Sinica
关键词
SiO2中空微球
前驱体法
LBL法
模板法
煅烧
voided SiO2 microsphere
modified precursor method
LBL method
template process
calcination
