高分子表面活性剂存在下超声辐照引发苯乙烯乳液聚合的研究

Study of Ultrasonically Initiated Emulsion Polymerization of Styrene in the Presence of Polymeric Surfactant

采用高分子表面活性剂(CMC-A9)和十二烷基硫酸钠(SDS)做乳化剂,用超声辐照乳液聚合方法制备了相对分子质量高(>106)的寡链聚苯乙烯纳米粒子。研究结果表明,在适当的反应条件下,CMC-A9的加入使反应速率大大提高,反应60min单体转化率能达到85%,制得直径30～60nm的聚苯乙烯胶乳粒子,乳胶粒子中含平均分子链数为3～20。CMC-A9或SDS质量浓度提高,能降低乳胶粒径和乳胶中所含的平均分子链数,增加聚合物相对分子质量。超声波输出功率对乳胶粒径影响不大。

Ultrasonically initiated emulsion polymerization of styrene employing polymeric surfactant CMC-A9 and sodium dodecyl sulfate(SDS) as emulsifier was investigated.High molecular weight (>106) and pauci-chain polystyrene nanoparticles of 30-60 nm diameters were prepared.Various effects on emulsion polymerization and the properties of latex were studied.The results indicated that increase of concentration of CMC-A9 and SDS,enhancement of ultrasonic power output and decrease of monomer content were advantageous to the improvement of polymerization rate.Under appropriate conditions,the monomer conversion could reach 85% in 60 min.The diameter of latex and chain number per particle decreased and the molecular weight of polymer increased with the increase of concentration of CMC-A9 and SDS.Ultrasonic power output had little effect on the diameter of the latex.