Benzothiophene is an under-explored monomer for free radical polymerization. Here we report the preparation of poly(benzothiophene-alt-maleic anhydride) (PBTMA) microspheres with high yield by self-stabilized precipitation polymerization. The chemical structure of the PBTMA copolymer was characterized by ¹H-NMR, ¹³C-NMR, FT-IR and MALDI-TOF MS analyses. The effects of various reaction parameters, including the reaction medium, the monomer concentration, the initiator concentration and the reaction time, on the morphology, particle size and molecular weight (M_n) of the resultant PBTMA microspheres were investigated systematically. The experimental results demonstrated that the PBTMA copolymer was an alternating copolymer, whose composition was independent of the monomer composition. Uniform PBTMA microspheres with the diameter in the range of 400 nm to 3000 nm and M_n up to 12 000 g mol⁻¹ were easily prepared. PBTMA had good solubility in common polar organic solvents and possessed much higher thermal stability than other maleic anhydride copolymers. PBTMA also showed interesting fluorescence properties both in the solid state and in solution. This research has laid the foundation for the further development of PBTMA copolymers as a new material.

中文翻译：

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自稳定沉淀聚合制备聚苯并噻吩-alt-马来酸酐微球的简便方法

苯并噻吩是一种尚未开发的自由基聚合单体。在这里，我们报告了通过自稳定沉淀聚合制备高产率的聚（苯并噻吩-马来酸酐）（ PBTMA ）微球。PBTMA共聚物的化学结构通过¹ H-NMR、¹³ C-NMR、FT-IR和MALDI-TOF MS分析来表征。反应介质、单体浓度、引发剂浓度和反应时间等各种反应参数对形貌、粒径和分子量的影响( M _n) 对所得 PBTMA 微球进行了系统研究。实验结果表明，PBTMA共聚物是一种交替共聚物，其组成与单体组成无关。易于制备直径在 400 nm 至 3000 nm 范围内且M _n高达 12 000 g mol ^-1的均匀 PBTMA 微球。PBTMA在普通极性有机溶剂中具有良好的溶解性，并且比其他马来酸酐共聚物具有更高的热稳定性。PBTMA 在固态和溶液中也显示出有趣的荧光特性。该研究为进一步开发PBTMA共聚物作为一种新材料奠定了基础。