乙酸乙烯酯无乳化剂乳液聚合的影响因素探讨

Influential factors on emulsion polymerization of vinyl acetate in absence of emulsifier

采用乙酸乙烯酯(VAc)在水中以过硫酸钾(KPS)和亚硫酸氢钠氧化还原体系作为引发剂进行无乳化剂乳液聚合,探讨了引发剂浓度、聚合温度、单体浓度和搅拌速度对聚合速率及转化率的影响。结果表明:当VAc质量分数为30%,KPS:VAc摩尔比为1:2 000,聚合温度10℃,反应时间10 h,搅拌速度80 r/min,时聚合产物聚乙酸乙烯的聚合度达到10 848;当VAc质量分数为35%时,聚合转化率可达到96%,聚合速率与引发剂浓度的0.944次方成正比;当搅拌速度达到200 r/min以上时,搅拌速度对聚合速率以及转化率影的响可以忽略。

Vinyl acetate （VAc） was subjected to emulsifier-free emulsion polymerization in water using the oxidation reduction system of potassium persulfate（KPS） and sodium bisulfite as an initiator. The effects of initiator concentration, polymerization temperature, monomer concentration and stirring speed on the polymerization rate and conversion rate were discussed. The results showed that the polymerization degree of the obtained polyvinyl acetate was 10 848 when the process conditions were as followed： 30% VAc by mass fraction, mole ratio of KPS and VAc of 1 ： 2 000, polymerization temperature 10℃ , reaction time 10 h, stirring speed 80 r/min. The conversion rate could reach 96% and the polymerization rate was in direct proportion to the 0.944th power of initiator concentration as the VAc content was 35% by mass fraction. The effects of stirring speed on the polymerization rate and conversion rate could be neglected at the stirring speed above 200 r/min.