Cinnamic monomers, which are useful chemicals derived from biomass, contain α,β-unsaturated carbonyl groups with an aromatic ring at the β-position. Homopolymers synthesized by addition polymerization of these compounds are expected to be innovative bio-based polymer materials, as they have both polystyrene and polyacrylate structures. However, polymerization of these compounds by many methods is challenging, including by radical methods, owing to steric hindrance of the substituents and delocalization of electrons throughout the molecule via unsaturated π-bonding. Herein we report that homopolymers of these compounds with molecular weights (M_n) of ~18,100 g mol⁻¹ and controlled polymer backbones can be synthesized by the group-transfer polymerization technique using organic acid catalysts. Additionally, these homopolymers are shown to have high heat resistance comparable to that of engineering plastics. Overall, these findings may open up possibilities for the convenient homopolymerization of cinnamic monomers to produce high-performance polymer materials.

肉桂单体，其是衍生自生物质有用的化学品，含有α，β不饱和羰基与在芳香环β位上。通过这些化合物的加聚反应合成的均聚物由于具有聚苯乙烯和聚丙烯酸酯结构，因此有望成为创新的生物基聚合物材料。然而，由于取代基的空间位阻和电子通过不饱和π键在整个分子中的离域化，通过许多方法，包括通过自由基方法，聚合这些化合物是具有挑战性的。在此我们报告这些化合物的均聚物的分子量（M _n）为〜18,100 g mol ^-1可以通过使用有机酸催化剂的基团转移聚合技术合成可控的聚合物主链。另外，这些均聚物显示出与工程塑料相当的高耐热性。总体而言，这些发现可能为肉桂酸酯单体的方便均聚以生产高性能聚合物材料开辟了可能性。