脂肪酸盐用于反相乳液中淀粉接枝反应乳化剂的研究

研究了以淀粉为基材、以丙烯酰胺(AM)和二甲基二烯丙基氯化铵(DMDAAC)为聚合单体、以脂肪酸盐及其复配物为乳化剂、采用反相乳液聚合技术合成接枝共聚物的方法。讨论了脂肪酸盐的金属离子种类、碳链长度、乳液形成方法、乳化剂组成、乳化剂用量对单体转化率、接枝率、接枝效率、产品特性黏数及絮凝效果的影响。结果表明,将单一的脂肪酸盐以一定比例进行复配得到的混合物的乳化效果较好,当m(油酸)∶m(油酸钠)=60∶40的复配物为乳化剂,w(乳化剂)=6%,V(油)∶V(水)=1 2∶1,n(AM)∶n(DMDAAC)=3∶1,c〔(NH4)2S2O8〕=3 5×10-4mol/L,t=6h,θ=45℃时,单体转化率达99 7%,接枝率达97 6%,接枝效率为97 9%,特性黏数为1120mL/g。

Study of Salts of Fatty Acid as Emulsifiers for Starch-Grafting Copolymerization in Inverse Emulsion

A graft copolymer was synthesized by copolymerization of starch with acrylamide(AM) and diallydimethylammonim chloride (DMDAAC) in inverse emulsion.The graft copolymerization was carried out in the systems of fatty acid and salt of fatty acid and their mixture respectively as emulsifier.Effects of molecular structure of emulsifier,preparation method of water in oil emulsion and proportion of mixture on the monomer conversion,grafting ratio,specific viscidity and flocculating effect were discussed.Result of experiments showed that calcium oleate and magnesium oleate as emulsifiers were better than sodium oleate and potassium oleate or oleic acid alone.When mixture of oleic acid and sodium oleate in mass ratio 60∶40 was used as emalsifier,w(emulsifier)=6%,V(oil)∶V(water)=12∶1,n(AM)∶n(DMDAAC)=3∶1,c(initiator)=35×10-4 mol/L,t=6 h,θ=45 ℃,the monomer conversion,grafting ratio,grafting efficiency and specific viscidity reached 997%,976%,979% and 1120 mL/g respectively.