Abstract: To overcome the limitations of conventional metal-based catalysts in polymer synthesis, poly(propylene carbonate) was synthesized through the alternating copolymerization of propylene oxide and CO2 using a metal-free two-component Lewis acid–base pair catalytic system comprising triethylborane and bis(triphenylphosphine)iminium chloride. Nuclear magnetic resonance and gel permeation chromatography analyses confirmed the capability of system to mediate efficient and controlled polymerization, with the resulting poly(propylene carbonate) showing a linear molecular weight increase over time and a narrow polydispersity index. Thermogravimetric analysis revealed a single-step thermal degradation process occurring between 150 ℃and 250?℃. The apparent activation energies were determined using the Kissinger, Kissinger–Akahira–Sunose, Madhusudanan–Krishnan–Ninan, and Flynn–Wall–Ozawa methods. Further kinetic analysis using the Coats–Redfern model indicated consistency with a reaction order of n?=?1/3, corresponding to a stochastic nucleation and subsequent growth mechanism.

Key words: poly propylene carbonate, thermal degradation, kinetics, metal-free catalysts