Unlocking the chemistry of PLA-based copolymers: activated benzaldehyde-DOX monomers from biobased α-hydroxy fatty acids as versatile comonomers to highly-loaded functional materials

Renewable α-Hydroxy Fatty Acids (αHFAs) were exploited as functional monomers in the synthesis of poly lactic acid (PLA)-based copolymers. Different fatty acids were converted into the corresponding αHFAs by means of a green α-chlorination procedure. Given their great potential as reactive species, the possible exploitation of these species as monomers for the synthesis of polyesters was explored. PLA was the polyester of choice, given its industrial significance. Different copolymers were synthesized, with different loadings of αHFA, with different chain lengths to determine their effects on the properties of the final materials. αHFA were, at first, loaded as free α-hydroxy acids, to assess their reactivity and ability to react with L-lactide. Once the successful incorporation of the αHFA along the chains was demonstrated, their reactivity as 1,3-dioxolan-4-ones (DOX) derivatives was investigated. Benzaldehyde-DOX derivatives were synthesized from the starting αHFA and employed for the reliable synthesis of PLA-based copolymers, proving an optimal reactivity even at high monomer loadings. The molecular weight, thermal, wettability and rheological properties of the copolymers were investigated, showing intriguing changes in the behavior with respect to a standard PLA.