丙烯酸甲酯共聚改性聚乙烯醇的研究

Study on Modification of Polyvinyl Alcohol by Copolymerization with Methyl Acrylate

丙烯酸甲酯(MA)作为第二单体与醋酸乙烯酯溶液共聚再醇解制备改性聚乙烯醇(PVA).通过正交实验进行优化,得出适宜聚合反应条件为:反应时间为5. 5 h,引发剂质量分数为0. 4%,MA质量分数为3%,溶剂质量分数为33. 3%.单体转化率达到87%.用红外光谱、X射线衍射、热重分析等实验方法对改性聚乙烯醇的结构和性能进行了表征.结果表明:随着MA用量的增加,共聚改性PVA大分子链中MA结构单元摩尔分数增大,共聚物的结晶度降低,热分解温度提高,其水溶性明显提高,吸湿率下降.

Modified polyvinyl alcohol(PVA) was prepared by solution copolymerization of vinyl acetate with methacrylate(MA) as the second monomer and then alcoholysis.The optimum polymerization conditions were obtained by orthogonal experiment as follows: reaction time was 5.5 h, initiator mass fraction was 0.4 %, MA mass fraction was 3 % and solvent mass fraction was 33.3 %.The monomer conversion rate reached 87 %.The structure and properties of the modified PVA were characterized by IR,XRD,TG and other experimental methods.The results show that with the increase of the amount of MA,the mole fraction of MA in the macromolecular chain of PVA modified by copolymerization increases,the crystallinity of the copolymer decreases,the thermal decomposition temperature increases,the water solubility of the copolymer increases obviously,and the moisture absorption rate decreases.