The polymer nanoparticles with size less than 100 nm can be prepared by surfactant-free emulsion polymerization (SFEP) with co-solvent, but it needs to be conducted in high temperature at over the azeotropic point of the solution. In the present study, the redox initiator of ammonium persulfate/ascorbic acid (APS/ASA) was applied to reduce the reaction temperature of SFEP with acetone as co-solvent. The effects of temperature, acetone content, monomer concentration, and initiator on the particle size of poly(methyl methacrylate) (PMMA) were investigated to control average diameter of PMMA nanoparticles (PNs) efficiently. The results showed that the PMMA nanoparticles with 45 nm in diameter and uniform size (PDI < 0.05) can be synthesized conveniently through controlling the ratio of APS/ASA.

中文翻译：

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在丙酮-水混合物中由过硫酸铵/抗坏血酸引发的亚 100 nm PMMA 纳米粒子的合成

尺寸小于100 nm的聚合物纳米粒子可以通过无表面活性剂乳液聚合（SFEP）与共溶剂进行制备，但需要在超过溶液共沸点的高温下进行。在本研究中，使用过硫酸铵/抗坏血酸 (APS/ASA) 的氧化还原引发剂来降低 SFEP 以丙酮为共溶剂的反应温度。研究了温度、丙酮含量、单体浓度和引发剂对聚甲基丙烯酸甲酯 (PMMA) 粒径的影响，以有效控制 PMMA 纳米粒子 (PNs) 的平均直径。结果表明，通过控制APS/ASA的比例，可以方便地合成直径为45 nm、尺寸均匀（PDI < 0.05）的PMMA纳米颗粒。