Synthesis of biodegradable polyesters by ring-opening copolymerization of cyclic anhydrides containing a double bond with 1,2-epoxybutane and one-pot preparation of the itaconic acid-based polymeric network

Abstract

Ring-opening copolymerizations of itaconic anhydride (IAn) or citraconic anhydride (CAn) with 1,2-epoxybutane (EB) were carried out using aluminum triisopropoxide (Al(OiPr)3) and magnesium diethoxide (Mg(OEt)2). The resulting copolymers were characterized for molar composition and sequences by FT-IR, 1H and 13C NMR spectra. The copolymers obtained using Al(OiPr)3 initiator were found to contain homosequences of EB, i.e., copolyesterethers (1a and 2a), while those produced by Mg(OEt)2 were alternating copolymers, i.e., polyesters (1b and 2b), irrespective of various feed monomer ratio. Differential scanning calorimetry analysis of the copolymers revealed a relationship between the glass transition temperature and the structure. One-pot preparation of itaconic acid-based highly cross-linked polymer was achieved through cleavage of exo-type double bond of IAn unit in the copolymers. Enzymatic degradation test for the films of cross-linked poly(IAn-co-EB) by Pseudomonas sp. and Rhizopus delemar lipase indicated that EB homosequence aided the enzymes to access the ester linkage in the cross-linked copolymers. The cross-linked poly(IAn-co-EB) films degraded moderately for 120 days in soil.