甲基丙烯酸甲酯在改性介孔分子筛SBA-15孔道中的溶液聚合

水热法合成了介孔分子筛SBA-15,分别用硅烷偶联剂KH-151,KH-560和KH-570对SBA-15进行了改性,将不同类型的改性介孔分子筛(M-SBA-15)作为"微反应器",把含MMA的甲苯溶液载入到"微反应器"中,通过溶液聚合法使得MMA在孔道内部形成聚合物.通过XRD,FTIR,N2吸附/脱附,GPC,1H-NMR,TG和DSC测试手段对M-SBA-15和PMMA/M-SBA-15复合材料以及孔道内PMMA进行了分析测试.研究表明,改性介孔分子筛仍保留了有序介孔材料的基本特性,M-SBA-15和相应的复合材料的比表面积、孔径以及孔容降低,表明PMMA载入到介孔分子筛的孔道中.与传统的溶液聚合所得的PMMA相比,介孔孔道内所得的PMMA的分子链的间规立构度有所提高,其分子量约为传统溶液聚合的十几倍,初始热稳定性明显提高,玻璃化转变温度提高9～11℃.此外,KH-151改性SBA-15载入最多的PMMA,所得的PMMA的分子量和玻璃化转变温度最高.

MMA SOLUTION POLYMERIZATION IN THE CHANNELS OF MODIFIED MESOPOROUS MOLECULAR SIEVES SBA-15

SBA-15 was synthesized by hydrothermal method,and modified with silane coupling reagents vinyl triethoxylsilane(KH-151),γ-glycidylpropyltrimethoxysilane(KH-560) and γ-methacryloxypropyl-trimethoxysilane(KH-570),respectively.Then different types of modified mesoporous sieves(M-SBA-15) were used as microreactors which were loaded with methyl methacrylate and initiator in toluene.Mesoporous channels were covered by PMMA in the form of thin coating via solution polymerization.M-SBA-15,PMMA/M-SBA-15 composites and PMMA polymerized in the channels were characterized by X-Ray diffraction(XRD),N2 adsorption/desorption,gel permeation chromatography(GPC),1H-nuclear magnetism resonance spectrum(1H-NMR),Fourier transform infrared spectra(FTIR),thermal gravimetric analysis(TGA) and differential scanning calorimeter(DSC).The results showed that modified mesoporous sieves and parts of the composites still retained the basic features of order mesoporous materials.Compared with SBA-15,BET surface areas,pore size and pore volume of both the modified mesoporous sieves and corresponding polymer composites decreased obviously.This confirmed that PMMA was loaded into the mesoporous channels.Molecular weight of PMMA in the channels of the mesoporous sieves was ten times more than that of traditional PMMA via solution polymerization.In addition,thus prepared PMMA exhibited higher initial thermal temperature,and glass transition temperature(an increase of 9-11 K) due to the little weak bonds formation and higher molecular weight.Furthermore,KH-151 modified SBA-15 loaded the highest PMMA content,and the PMMA possessed the highest molecular weight and Tg.