Phase Transition and Crystallization of Comb‐Like Materials Based on Poly(Vinyl Cyclohexene Carbonate) and Mercaptan via Thiol‐Ene Click Reaction

ABSTRACT The comb‐like transition material, which can absorb and store external heat to achieve the regeneration and utilization of thermal energy, is an important green energy material. In this paper, poly(vinyl cyclohexane carbonate) (PVCHC) with double bonds in the side chains is formed by copolymerization of vinyl cyclohexene oxide (VCHO) with CO 2 . Then a series of comb‐like polymers with various lengths of alkyl chains (PVCHC‐ g ‐R) are synthesized through PVCHC and different chain lengths of thiol via thiol‐ene click reaction. The structure of comb‐like polymers is investigated by FT‐IR, 1 H NMR. It is found that the grafting rate is about up to 95%. Differential Scanning Calorimetry (DSC) testing reveals that phase‐transition temperature ( T m ) and phase‐change enthalpy( ΔH m ) of PVCHC‐ g ‐R increased from 19.5°C and 65.0 J·g −1 to 50.0°C and 129.8 J·g −1 with the number of carbon atoms of the thiols increased from 14 to 18, the melting enthalpy nearly doubled. Furthermore, XRD and temperature‐programmed infrared spectroscopy confirmed a transition in crystallinity and crystal conformation from an ordered to a disordered state. This work provides a promising strategy to achieve crystallized CO 2 ‐based copolymers and affords a facile approach to develop the structuralized polymeric materials from the molecular regulation aspect.