Polyesters with bio-based ferulic acid units: crosslinking paves the way to property consolidation

Aromatic–aliphatic polyesters can be prepared as bio-based materials by incorporating monomers from biogenic sources. Here, 2-methyl (E)-3-(4-(2-hydroxyethoxy)-3-methoxyphenyl)acrylate, a derivative of ferulic acid, was synthesised and inserted into the structure of aliphatic and aromatic–aliphatic polyesters as a comonomer. Terpolymers with high relative molar masses Mw from 50 000 to 100 000 g mol−1 can be successfully prepared by transesterification polycondensation in the melt. Incorporation of ferulate units with intact double bonds is proven by NMR spectroscopy. Insertion of low molar amounts of ferulate units reduces the crystallinity of the base polyesters, but enhances the glass transition temperature. It is demonstrated that the materials after melt processing to a suitable shape (fibres, parts, films) can be crosslinked by electron beam irradiation, which enhances the stability of the materials.