十一烯酸基乳化剂制备及应用研究

利用十二醇(DA)与十一烯酸(UA)/马来酸酐(MAH)共聚物通过酯化反应制备了UMA-DA聚合物，并将聚合物作为乳化剂用于UA与甲基丙烯酸甲酯(MMA)的乳液聚合中。FT-IR分析表明：DA中的羟基与UMA共聚物中的酸酐发生了反应。¹H NMR结果表明：在δ 3.2~3.4处有明显的—O—CH₂—质子信号，表明成功制备了UMA-DA共聚物。通过表面张力法对UMA皂化物的临界胶束浓度(CMC)值进行了测定，UMA-DA的CMC值为9.6 g/L，此时表面张力γ_CMC为23.04 mN/m, UMA-DA的γ_CMC值要远低于纯水(71.97 mN/m)。在乳液聚合时，随UMA-DA用量的不断增加，乳液粒径和粒径分散系数(PDI)增大，凝胶率逐渐减小。当自制乳化剂UMA-DA用量为总单体的10%且UA与MMA质量比10 : 90时乳液较为稳定，总单体转化率为98.1%。

Preparation and Application of Emulsifier Based on Undecylenic Acid

Undecylenic acid/maleic anhydride-dodecanol (UMA-DA) polymer was prepared by esterification reaction using dodecanol(DA) and undecylenic acid(UA)/maleic anhydride(MAH) as copolymer.The polymer is used as an emulsifier in the emulsion polymerization of UA and methyl methacrylate(MMA). FT-IR analysis showed that the self-made undecylenic acid/maleic anhydride(UMA) copolymer acted with DA by esterification of an acid anhydride with a hydroxyl group.The proton signal at δ 3.2-3.4 of —O—CH₂—in ¹H NMR show that UMA-DA copolymer was prepared successfully.The critical micelle concentration(CMC) value of UMA saponification was determined by surface tension method. The CMC value of UMA-DA was 9.6 g/L, and the surface tension γ_CMC was 23.04 mN/m. The γ_CMC value of UMA-DA is much lower than that of pure water(71.97 mN/m). The particle size and particle size distribution index(PDI) increased, butthe gel rate gradually decreasedwith the increase of UMA-DA dosage in emulsion polymerization. The emulsion is relatively stable, and the total monomer conversion rate reaches 98.1% when the amount of the self-made emulsifier UMA-DA is 10% of the total monomer and the ratio of UA to MMA is 10 : 90.