【摘要】 通过气相沉积法,分别用三甲基氯硅烷(TMCS)和六甲基二硅氮烷(HMDSZ)对HMS介孔分子筛表面进行甲基接枝改性;分别采用XRD、N2-吸附、FTIR2、9Si NMR和TG等手段对样品进行表征,并测定了样品的亲水性能。结果表明,两种硅烷都可以在HMS表面接枝,接枝后分子筛的介孔结构依然保持;但是,HMDSZ的接枝效果要明显优于TMCS,前者能接枝引入更多的甲基;拟定的接枝反应机理可以合理解释上述结果:Si-OH被TMCS直接氯化形成羟基硅烷和Si-Cl,羟基硅烷的挥发降低了TMCS的利用率,Si-Cl的水解(形成Si-OH)间接保留了HMS表面的硅羟基(Si-OH)。更多还原

【Abstract】 HMS mesoporous molecular sieve was methyl-grafted by the chemical vapor deposition(CVD) method using trimethylchlorosilane(TMCS) and hexamethyldisilazane(HMDSZ),respectively.The samples were characterized by XRD,N2-adsorpton,FTIR,29Si NMR and TG,respectively,and the hydrophilicity of samples was measured.The results show that the mesoporous characteristics of all samples are still kept after the methyl-grafting treatment using TMCS and HMDSZ while HMDSZ performs more effectively than TMCS because HMDSZ can graft more methyl-groups.The experiment results can be reasonably explained by the proposed grafting reaction mechanism.Si-OH was directly chlorinated by TMCS to form OH-containing silane and Si-Cl group.The volatilization of OH-containing silane decreased the grafting efficiency of TMCS and the hydrolysis of Si-Cl to form Si-OH indirectly retained the surface Si-OH of HMS.更多还原