接枝聚合-大分子反应法在交联聚乙烯醇微球表面接枝聚偕胺肟的研究

STUDIES ON GRAFTING POLY(AMIDOXIME) ON CROSSLINKED POLYVINYL ALCOHOL MICROSPHERES VIA GRAFT POLYMERIZATION-POLYMER REACTION METHOD

以硫酸铈铵为引发剂,实施了丙烯腈(AN)在交联聚乙烯醇(CPVA)微球表面的接枝聚合,制备了接枝微球CPVA-g-PAN,然后以盐酸羟胺为试剂,通过偕胺肟(AO)化转变,将接枝的PAN转变为聚偕胺肟(PAO),制得了接枝有聚偕胺肟的功能微球CPVA-g-PAO,采用红外光谱(FTIR)法、扫描电子显微镜(SEM)及zeta电位测定等法,对功能微球CPVA-g-PAO的化学结构及物理化学特性进行了表征,重点考察了各主要因素对接枝PAN的偕胺肟化转变反应的影响,也以脲酸为模型分子,初探了功能微球CPVA-g-PAO对生物分子的吸附性能.实验结果表明,在腈基的偕胺肟转变反应中,介质pH与反应温度是两个主要影响因素,对于本研究体系,适宜的反应条件是温度70℃,介质pH=6～7.在此条件下,反应4h,可使腈基转化率达到72%.在较大的pH范围内,功能微球CPVA-g-PAO的zeta电位为数值较大的正值,对内源性代谢毒素分子脲酸具有很强的吸附作用,吸附容量达95mg/g。

The graft polymerization of acrylonitrile on crosslinked polyvinyl alcohol（CPVA） microspheres was performed by using cerium ammonium sulfate as initiator,and grafted microspheres CPVA-g-PAN were prepared.Subsequently,the grafted PAN was converted into poly（amidoxime）（PAO） via amidoximation reaction with hydroxylamine hydrochloride as reagent,resulting in the functional microspheres CPVA-g-PAO.The chemical structure and physicochemistry characters of CPVA-g-PAO microspheres were adequately characterized by infrared spectrum（FTIR）,scanning electron microscope（SEM） and determining zeta potential.The effects of main factors on the amidoximation transform reaction of the grafted PAN were studied with emphasis,and the adsorption property of the functional microspheres CPVA-g-PAO for some biomolecules was examined preliminarily with uric acid as a model biomolecule.The experimental results show that in the a midoximation transform reaction of nitrile groups,medium pH and reaction temperature are two main factors.For this system,the adequate pH value and temperature are 6 ～ 7 and 70℃.Under the fitting conditions,the conversion ratio of the nitrile group of the grafted PAN reaches 72% for 4 h.In a wider pH range,the zeta potential of the microspheres CPVA-g-PAO is a greater positive value.They exhibit strong adsorption ability for uric acid,a toxic endogenrsis molecule,and the adsorption capacity can get up to 95 mg /g.