聚N-异丙基丙烯酰胺/纳米SiO_2复合水凝胶的合成及溶胀性能

通过纳米SiO2的表面功能化,在其表面引入乙烯基功能基团,在H2OTHF的混合溶剂中,超声分散后,交联剂N,N′亚甲基双丙烯酰胺存在时,于25℃下使其与N异丙基丙烯酰胺共聚,制得聚N异丙基丙烯酰胺纳米SiO2复合水凝胶,并用FTIR和SEM对产物进行了表征.研究了凝胶的溶胀动力学,消溶胀动力学和温度敏感性.实验结果表明,纳米SiO2的引入,改善了聚N异丙基丙烯酰胺水凝胶在低温时的溶胀性能和在高温时对水的释放性能,并讨论了引起这些性能改变的原因.

SYNTHESIS AND SWELLING PROPERTIES OF POLY(N-ISOPROPYLACRYLAMIDE)/NANO-SiO_2 COMPOSITE HYDROGELS

The nano-composite hydrogels were prepared by the radical graft copolymerization of N-isopropylacrylamide onto the surface of nano-SiO_2 particles treated with vinyltrimethoxysilane in a mixture solvent of H_2O/THF at 25℃,and N,N′-methylene bisacrylamide (BIS) was used as the crosslinking agent.The products were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy.These composite hydrogels exhibit higher swelling ratio than the usual poly(N-isopropylacrylamide) hydrogels at low temperature (15℃) and more excellent water release behavior at high temperature (50℃).The swelling ratio of hydrogel H1,which has no nano-SiO_2 component,is about 29 at 15℃,by contrast,the swelling ratio of hydrogel H4 which contents 5% nano-SiO_2 component is about 35 at the same temperature.At the same time,the water release behavior of hydrogel H4 shows an almost linear form,which is very essential to the controlled drug delivery systems.The reasons causing the property improvement of the hydrogels were discussed.