Four new monomers based on the naturally occurring pentacyclic triterpenoid oleanolic acid (OA) were synthesized by introducing a methacrylate group at either the hydroxyl or carboxylic acid positions. After establishing their (in)solubility in a range of solvents, three monomers could notably be polymerized in the green solvent N-butyl-2-pyrrolidone (NBP), in which soluble polymers were obtained. Dithiobenzoate-mediated radical polymerization of all four monomers led to polymethacrylates with theoretical number-average molecular weights (M_n) of up to 45 kg/mol and single-detection size-exclusion chromatography M_n values of up to 24 kg/mol. The purified polymers show thermal stabilities in the range of 300–350 °C and high glass-transition temperatures, up to 220 °C.

中文翻译：

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齐墩果酸衍生的高玻璃化转变温度甲基丙烯酸聚合物


通过在羟基或羧酸位置引入甲基丙烯酸酯基团，合成了四种基于天然存在的五环三萜类齐墩果酸 （OA） 的新单体。在确定它们在一系列溶剂中的（不）溶性后，三种单体可以在绿色溶剂 N-丁基-2-吡咯烷酮 （NBP） 中显着聚合，从而获得可溶性聚合物。所有四种单体的二硫代苯甲酸酯介导的自由基聚合导致聚甲基丙烯酸酯的理论数均分子量 （M_n） 高达 45 kg/mol，单次检测体积排阻色谱 M_n 值高达 24 kg/mol。纯化的聚合物在 300–350 °C 范围内表现出热稳定性，玻璃化转变温度高达 220 °C。