复合乳化剂在制备纳米乳胶粒子中的作用

Function of Complex Emulsion in Preparation of Nano Latex Particles

以烯丙氧基壬基酚聚氧乙烯醚硫酸铵(ANS)和十二烷基硫酸钠(SDS)为乳化剂,甲基丙烯酸甲酯(MMA)为单体,进行饥饿滴加半连续乳液聚合,制备了PMMA纳米乳胶粒子。考察了ANS和SDS用量对聚合瞬时转化率、总转化率、乳胶粒子粒径和粒子数目的影响,并用Zeta电位值讨论了纳米乳液的稳定性。结果表明:MMA单体瞬时转化率在79%以上,聚合过程符合饥饿条件下半连续乳液聚合的特征。在0.8%ANS和0.9%SDS乳化剂作用下,最终纳米乳胶粒子的体均粒径为41.1 nm,粒子数目达到11.2×1018/L,乳液稳定性良好,固含量达到了32.0%。从以上结果分析,反应性乳化剂ANS可以改善单体饥饿滴加半连续聚合过程的稳定性。

Nano latex particles were synthesized by methyl methacrylate （MMA） monomer-starved semibatch emul- sion polymerization, using ammonium allyloxtmethylate nonylphenol ethoxylates sulfate （ANS） and sodium dode- cyl sulfate （SDS） as surfaetant. Effects of ANS and SDS dosages on MMA instantaneous conversions, total conver- sion and latex particle size and number were discussecL The nano latex stability was measured based on the Zeta potential value. The results show the MMA instantaneous conversion was above 79 %, it was one of characteriza- tion of starved feed semibatch emulsion. When the amount of ANS and SDS was 0. 8% and 0. 9%, respectively, the volume average particle size of final nano latex particle was 41. 1nm; the particle number in a unit volume was 11.2 × 1018/L. The final latex was in the good stability and the solid content was 32.0%. Based on the results ob- tained above, the ANS as reactive emulsifier can improve the latex stability in the monomer-starved semibatch e- mulsion polymerization.