Synthesis of Random, Gradient, and Block-like Terpolycarbonates via One-Pot Terpolymerization of Epoxide, CO<sub>2</sub>, and Six-Membered Cyclic Carbonates
Zan Gao, Bo Gao, Shuaiming Meng, Zhenjie Yang, Zhuang-Zhuang Liang, Zhiqiang Sun, Yanchuan Zhou, Xuan Pang
Abstract
Multi-polymerization is regarded as a valuable strategy to tailor material performances by incorporating well-chosen monomers and tuning monomer sequence distributions in the polymer backbones. Despite that considerable advances have been made in the past decades, the modification of CO 2 -based polycarbonate materials is still in its infancy. In this contribution, a series of polycarbonate terpolymers with diverse chain structures were fabricated through a dissymmetric Cr complex-catalyzed one-pot terpolymerization of cyclohexene oxide (CHO), CO 2 with six-membered cyclic carbonates (6CCs). The reaction conditions (temperature, feeding ratio, and CO 2 pressure) as well as the 6CC substituents played a critical role in tailoring the sequence distributions of CHO/CO 2 /6CC terpolymers from random to gradient or block-like sequences. It was noteworthy that the average lengths of both sequences could be modulated by adjusting the feeding monomer ratios or reaction temperature, as detected by quantitative 13 C NMR spectroscopy of purified terpolymers. Besides, DSC revealed that the glass-transition temperature of the obtained terpolymers had a wide range of 69.5–115.5 °C based on the polymer architecture.