Thermal, structural and degradation properties of an aromatic-aliphatic polyester built through ring-opening polymerisation

The novel biodegradable aromatic-aliphatic polyester, poly(2-(2-hydroxyethoxy)benzoate, was explored through thermal analysis, X-ray diffraction, dynamic mechanical analysis and comparative bio and catalysed degradation. The polyester is a product of ring opening polymerisation (ROP) of 2,3-dihydro-5H-1,4-benzodioxepin-5-one catalysed by an aluminium salen catalyst. Thermal and mechanical characterisation showed that the polyester had a Tg of nearly 27 ºC and crystallisation ability when cooled from melt, providing an insight to potential biomedical and compatibiliser applications. These thermal and mechanical properties can be tuned by altering the polymer’s molecular weight. The crystal structure has been also determined through wide-angle X-ray diffraction (WAXD). The polymer can be enzymatically degraded, but this process is slow compared to the rapid degradation by exploiting the monomer-polymer equilibrium catalysed by the aforementioned aluminium salen complex.