微米级接枝微粒PMAA/SiO_2的制备与表征  

Preparation and Characterization of Micron-sized Grafting Particles PMAA/SiO_2

作　　者：汪剑[1] 高保娇[1] 

机构地区：[1]中北大学化学工程系,太原030051

出　　处：《应用化学》2008年第5期573-577,共5页Chinese Journal of Applied Chemistry

基　　金：山西省自然科学基金资助项目(MZ20020402)

摘　　要：使用偶联剂γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH-570)对微米级硅胶进行表面化学改性,将双键引至SiO2粒子表面,采用溶液聚合法将甲基丙烯酸(MAA)接枝于硅胶微粒表面(graft from法),制得了接枝微粒PMAA/SiO2。采用红外光谱(FTIR)与热重分析法(TG)对PMAA/SiO2的化学结构与组成进行了表征,用扫描电子显微镜(SEM)观察了接枝微粒的形貌,探索了各种因素对接枝率的影响。结果表明,采用graftfrom法可顺利地将MAA接枝于硅胶微粒表面;在接枝聚合过程中,已接枝到硅胶表面的聚合物层对后续的接枝聚合会形成阻力。接枝率随单体浓度的增大而增大,当单体浓度超过一定值时(ω(单体)≥3%)接枝率不再变化;随引发剂用量的增大及温度的升高,接枝率均呈现先上升后下降的变化规律。制备高接枝率微粒的适宜条件为:温度为70℃、ω(单体)=3%、ω(引发剂用量)=0.6%。Micron-sized silica gel was chemically modified with 3-methacryloxypropyl trimethoxysilane （ MPTMS, KH-570） as coupling agent. Double bonds were introduced onto the surface of silica gel particles, and modified particles MPS-SiO2 were obtained. The poly methyl acrylic acid （PMMA） was grafted on the surface of particles MPS-SiO2 with the method of ＂ graft from＂, and grafted particles PMMA/SiO2 were prepared. The chemical structure of the grafed particle PMMA/SiO2 was characterized by means of infrared spectroscopy （FTIR） and thermogravimetry（ TG）, and the morphology of the grafting particle PMMA/SiO2 was observed. The experimental results show that the graft polymerization of methyl acrylic acid （MAA） onto the surface of silica gel particles can be successfully realized with the method of ＂graft from＂. During the graft polymerization, the grafted polymer layer was a hindrance to the subsequent graft polymerization. When the grafted polymer layer reached to a certain density via overlapping and entwisting, a kinetic barrier was built up. There were several factors affecting the grafting degree of polymer, such as monomer concentration, initiator amount and temperature. The grafting degree of polymer increased with the increase of the monomer concentration, and the grafting degree unchanged when the concentration of monomer was over 3%. When the amount of initiator increased or temperature rose, the grafting degree of polymer firstly increased and then decreased. The preparation conditions for the maximum grafting degree were temperature was 70 ℃, the concentration of monomer was 3% and the amount of initiator was 0. 6%.

关 键 词：甲基丙烯酸 硅胶 接枝聚合 溶液聚合 接枝度 

分 类 号：O631[理学—高分子化学]