Emulsion Copolymerization of Methyl Methacrylate/Butyl Acrylate/Iodine System to Monosize Rubbery Nanoparticles Containing Iodine and Triiodide Mixture
Emulsion Copolymerization of Methyl Methacrylate/Butyl Acrylate/Iodine System to Monosize Rubbery Nanoparticles Containing Iodine and Triiodide Mixture
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甲基丙烯酸甲酯/丙烯酸丁酯/碘体系乳液共聚制备含碘和三碘化物混合物的橡胶纳米粒子
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
H. Mohammadi
中科院分区：
文献类型：
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作者：
H. Riazi;N. Mohammadi;H. Mohammadi
采用乳液聚合法制备了粒径约为95 nm的单粒径聚甲基丙烯酸甲酯-丙烯酸共丁酯橡胶纳米颗粒，其中碘和三碘化物的摩尔比为2.78。以焦亚硫酸钠和过硫酸钾为氧化还原引发体系，对碘和双单体混合物进行聚合。用紫外可见光谱法对共聚过程中碘向三碘化物的演化过程进行了跟踪。在单体混合物中加入碘并进行共聚，不仅使共聚物的平均分子量降低了30%，而且形成了更多富含mma的链。氧化还原引发体系还将26%的初始碘分子转化为三碘化物，其余的碘分子被包封为碘分子。在热退火过程中，三碘化物分解为碘和碘化物的速率低于碘的蒸发速率，使热重和热流曲线变宽。
Monosize poly(methyl methacrylate-co-butyl acrylate) rubbery nanoparticles, approximately 95 nm in diameter, containing iodine and triiodide with a molar ratio of 2.78 of the former to the latter, were synthesized by emulsion polymerization. Iodine and the two-monomer mixture were polymerized by sodium metabisulfite and potassium persulfate as a redox initiation system. Iodine evolution to triiodide during the copolymerization was traced by ultraviolet–visible spectroscopy. Iodine addition to the monomer mixture and its copolymerization not only reduced the copolymer average molecular weight by 30%, but also led to the formation of more MMA-enriched chains. The redox initiation system also changed 26% of initial iodine molecules into triiodide, while the rest were encapsulated as molecular iodine. During thermal annealing, the lower rate of triiodide decomposition into iodine and iodide in comparison with the iodine evaporation rate broadened both thermogravimetric and heat flow curves.