Yamamoto Tetsuya, Tsutsumi Kazuya, Maeda Shinya
Department of Chemical Systems Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Department of Materials Design Innovation Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
ACS Omega. 2022 Aug 4;7(32):28556-28560. doi: 10.1021/acsomega.2c03351. eCollection 2022 Aug 16.
Hollow polymer particles are applied in various fields owing to their high specific surface area and inner volume. The hollow regions in such particles are generally synthesized using a template. However, chemical agents must be used to remove the templates, which is associated with a high environmental load. To address this problem, we previously established a method for synthesizing hollow polymer particles without a template. However, the mechanism underlying this synthesis was unclear, which this study aimed to rectify. First, azo compounds were dissolved in a styrene monomer phase, and soap-free emulsion polymerization was performed to produce polystyrene particles. The azo compounds were incorporated into the polystyrene particles from the monomer phase at a polymerization temperature greater than the melting point of the azo compounds. Finally, the polystyrene particles were heated at a temperature greater than the 10 h half-life temperature of the azo compounds to emit nitrogen gas, and the azo compounds were decomposed to prepare the hollow regions in the polystyrene particles. However, the resulting particles were not hollow when the azo compound was not incorporated into the polystyrene particles. By comparing the melting behavior of different azo compounds, this study elucidates the mechanism underlying our template-free method for synthesizing hollow polystyrene particles.
中空聚合物颗粒因其高比表面积和内部容积而被应用于各个领域。此类颗粒中的中空区域通常使用模板合成。然而，必须使用化学试剂来去除模板，这会带来高环境负荷。为了解决这个问题，我们之前建立了一种无模板合成中空聚合物颗粒的方法。然而，这种合成的潜在机制尚不清楚，本研究旨在纠正这一点。首先，将偶氮化合物溶解在苯乙烯单体相中，进行无皂乳液聚合以制备聚苯乙烯颗粒。在聚合温度高于偶氮化合物熔点的情况下，偶氮化合物从单体相被纳入聚苯乙烯颗粒中。最后，将聚苯乙烯颗粒在高于偶氮化合物10小时半衰期温度的温度下加热以释放氮气，并且偶氮化合物分解以在聚苯乙烯颗粒中制备中空区域。然而，当偶氮化合物未被纳入聚苯乙烯颗粒时，所得颗粒不是中空的。通过比较不同偶氮化合物的熔化行为，本研究阐明了我们无模板合成中空聚苯乙烯颗粒方法的潜在机制。
