Facile synthesis of recyclable polythioimidocarbonates via aromatization-driven alternating copolymerization of para-quinone methide and isothiocyanates†

The efficient and controllable alternating copolymerization of para-Quinone Methide (p-QM) is rare and challenging. The aromatization-driven alternating copolymerization of p-QM with isothiocyanates is explored for the first time under mild conditions. In the presence of the key catalyst m-phthalic acid and the initiator TBD, the reaction can efficiently produce completely alternating polythioimidocarbonates with narrow molecular weight distributions and high molar mass (up to 103.6 kg mol⁻¹). Experimental studies and DFT calculations suggest that m-phthalic acid plays a synergistic catalytic role. Remarkably, copolymers can be recycled back into monomers with excellent yields under vacuum at a temperature of 190 °C in just a few minutes without solvents or catalysts.