One-Step Syntheses of Photocurable Polyesters Based on a Renewable Resource

The facile design of polyester biomaterials has emerged as an important aspect of polymer synthesis. As opposed to thermoplastics, thermosets are especially attractive for applications in the biomedical fields because they retain their geometry and experience a linear loss of both mass and mechanical properties during degradation. Herein, we report the design of several polyester thermosets based on photocurable prepolymers composed of itaconic acid and various polyols. Itaconic acid is a renewable resource and a component of known biomaterials that is demonstrated to be compatible with thermal polyesterification. This polymerization strategy results in photocurable branched polyester prepolymers in a single and facile step. The cross-linking density and, therefore, the rigidity of the photocured thermosets can be controlled by the addition of a comonomer, such as adipic acid or succinic acid. Additionally, dimethyl itaconate is an ideal monomer for enzymatic polymerization, as demonstrated by the synthesis of linear poly(1,4-cyclohexanedimethanol itaconate), poly(PEG itaconate), and poly(3-methyl-1,5-pentanediol itaconate-co-3-methyl-1,5-pentanediol adipate). Novel polyester thermosets designed from these two polymerization strategies achieved Young's modulus, ultimate tensile stress, and rupture strain values of 0.17-398.14 MPa, 0.11-18.20 MPa, and 5-198%, respectively. As all of the monomers used in these materials have previously been utilized in other biocompatible polymers, cytotoxicity was expected to be minimal. In order to verify this hypothesis, an ATP-luminescence assay was conducted with Swiss albino 3T3 fibroblasts. On the basis of preliminary data, we believe that itaconate-based polyesters are versatile, making them excellent candidates as future biomaterials.