在聚合物微球HEMA/NVP表面接枝聚合甲基丙烯酸的研究

Studies on Graft Polymerization of Methacrylic Acid on Surfaces of Copolymeric Microspheres NVP/HEMA

采用悬浮聚合法制备了甲基丙烯酸羟乙酯与N-乙烯基吡咯烷酮的交联共聚微球;接着用甲基丙烯酰氯对交联微球进行了表面化学改性,将可聚合双键引入微球表面,制得了改性微球;然后,用"接出"法实施了甲基丙烯酸(MAA)在改性微球表面的接枝聚合,得到了接枝微球。用红外光谱法对几种微球的化学结构进行了表征,使用扫描电镜观察了形貌;考察了对MAA接枝聚合的主要影响因素。结果表明,交联微球在表面改性后,可顺利地实现MAA在微球表面的接枝聚合;在接枝聚合过程中,微球表面所产生的接枝聚合物层会形成动力学位垒,反应12h后接枝度不再变化,且在接枝度-温度与接枝度-引发剂用量曲线上出现最高点;接枝聚合适宜的反应温度为70℃,引发剂用量为单体质量的0.3%。对碱性蛋白的吸附性能的观察表明,在氢键与静电相互作用的协同作用下,接枝微球对溶菌酶具有很强的吸附能力。

The crosslinking copolymerization of 2-hydroxyethyl methacrylate and N-vinylpyrrolidone were performed with suspension polymerization method,resulting in the crosslinked microspheres.It was chemically modified with methacryloyl chloride to introduce polymerizable double bonds.Then,the graft polymerization of methacrylic acid（MAA） on the surfaces of modified microspheres was conducted by adopting ＂grafting from＂ method.The chemical structures and morphology of the various microspheres were characterized by FTIR and SEM.The factors influenced the graft polymerization were investigated.The results showed that methacrylic acid can be grafted favorably on the modified microspheres.During the graft polymerization process,the layer of grafted polymer will form a kinetics barrier which leads to no longer varying of the grafting degree of PMAA after 12 h and appear a maximum on the relationship curves of the grafting degree vs temperature and vs amount of initiator.For this graft polymerization system,the suitable temperature and amount of the initiator are 70℃ and 0.3% of the monomer mass,respectively.The test of the adsorption ability of the grafted microspheres towards model basic protein lysozyme indicated that the microspheres possess very strong adsorption ability for lysozyme due to cooperative effect of the hydrogen bond and electrostatic interaction.