Improving the thermal stability of poly(cyclohexylene carbonate) by in situ end-capping

Aliphatic polycarbonates derived from carbon dioxide and epoxides are drawing increasing attention from both academic and industrial researchers due to their biodegradability and partially renewable raw material resource. Of all the aliphatic polycarbonates investigated, poly(cyclohexene carbonate) (PCHC) is recognized as highly potential candidates thanks to its high glass transition temperature (Tg) which can bridge the shortcomings of commercialized biodegradable materials. Meanwhile, polymers with high Tg require higher processing temperature during compounding and subsequent casting in mold. It is therefore necessary to investigate the property changes of PCHC during its multiple thermal processing. In this work, the effect of several thermal stabilizers on the thermal stability and mechanical properties of PCHC was studied. The results showed that end-capping by maleic anhydride is the best approach to improve the thermal stability and to maintain the mechanical properties of PCHC. The possible mechanism for improving the thermal stability of PCHC was further analyzed by Py-GC/MS and 1H NMR. Partial in situ end-capping of PCHC could mitigate the back-biting reaction at elevated temperature and consequently improved the thermal stability.