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使用偶联剂γ-氨丙基三甲氧基硅烷(AMPS)对微米级硅胶微粒进行表面化学改性,将氨基引入硅胶微粒表面,构成氨基-Ce(Ⅳ)盐氧化-还原引发体系。研究了在其作用下对苯乙烯磺酸钠(SSS)在硅胶微粒表面的接枝聚合,制得了具有较高接枝度(18g/100g)的接枝微粒PSSS/SiO2。采用FTIR、SEM及TGA等方法对接枝微粒进行表征。考察了对该表面引发接枝聚合体系接枝度影响的主要因素。结果表明,氨基-Ce(Ⅳ)盐体系可以有效地引发乙烯基单体在固体微粒表面的接枝聚合,氨基的质子化对产生自由基的引发步骤具有负影响;为提高PSSS的接枝度,引发剂溶液(铈盐+硫酸)宜采用滴加的方式加入;适宜的单体浓度为14(wt)%;接枝聚合宜在50℃下进行。接枝微粒PSSS/SiO2是一种功能复合微粒,凭借离子交换作用,对重金属离子和稀土离子均可产生强的吸附作用。
The micro-silica particles were surface chemically modified by using γ-aminopropyltrimethoxysilane (AMPS). The amino group was introduced into the surface of the silica particles to form the amino-Ce (Ⅳ) salt oxidation-reduction system. The grafting polymerization of sodium styrenesulfonate (SSS) on the surface of silica particles was studied. The PSSS / SiO2 grafted particles with high grafting degree (18g / 100g) were prepared. The grafted particles were characterized by FTIR, SEM and TGA. The main factors affecting the degree of grafting of the surface-initiated graft polymerization were investigated. The results show that the amino-Ce (Ⅳ) salt system can effectively initiate the graft polymerization of vinyl monomers on the surface of solid particles, and the protonation of amino groups has a negative effect on the initiation of free radicals. In order to improve the degree of grafting of PSSS , Initiator solution (cerium salt + sulfuric acid) should be added dropwise manner; suitable monomer concentration of 14 (wt)%; graft polymerization should be carried out at 50 ℃. Graft particles PSSS / SiO2 is a functional composite particles, by virtue of ion exchange, heavy metals and rare earth ions can produce strong adsorption.