Modular approach to synthesis of property tunable biodegradable polyesters derived from poly(ϵ-caprolactone)

Abstract

Surface erosion is desired in degradable polymers especially for drug delivery applications. The authors recently described a ground-up design strategy for the synthesis of surface eroding poly(a-hydroxy acids) through judicious introduction of lipophilicity. In the present study, the authors describe the synthesis and characterisation of poly(e-caprolactone) (PCL) with tunable thermal properties. In the first step macromerdiols of differing hydrophobicities were assembled by initiating the ring opening polymerisation of e-caprolactone monomer to varying degrees of polymerisation using alkanediol initiators of varying chemical make-up. These macromerdiols were then assembled into higher molecular weight polymers (M w 30 000 to 120 000 g mol 21 , polydispersity index ranging from 2 to 5) through covalent linking using diacid chlorides of different carbon chain length, thereby impacting the physico-chemical characteristics of the polymers in two distinct well defined steps. These polyesters exhibited different solubility, glass transition temperature (T g ) and melting temperature (T m ) from pure PCL. Based on the authors' past work these nanoengineered PCLs may be expected to undergo surface erosion.