Enhancing the Properties of Poly(ε-caprolactone) by Simple and Effective Random Copolymerization of ε-Caprolactone with p-Dioxanone

Abstract

We have developed a straightforward strategy to obtain semicrystalline and random copolymers of ε-caprolactone (CL) and p-dioxanone (DX) with thermal stabilities similar to poly(ε-caprolactone), PCL, but with a faster hydrolytic degradation rate. CL/DX copolymers are promising inks when printing scaffolds aimed for tissue engineering. Such copolymers behave similar to PCL and resorb faster. The copolymers were synthesized by bulk ring-opening copolymerization, achieving a high yield; a molecular weight, M_n, of 57-176 kg mol^-1; and an inherent viscosity of 1.7-1.9 dL g^-1. The copolymer microstructure consisted of long CL blocks that are separated by isolated DX units. The block length and the melting point were a linear function of the DX content. The copolymers crystallize as an orthorhombic lattice that is typical for PCL, and they formed more elastic, softer, and less hydrophobic films with faster degradation rates than PCL. Relatively high thermal degradation temperatures (above 250 °C), similar to PCL, were estimated by thermogravimetric analysis, and copolymer filaments for three-dimensional printing and scaffolds were produced without thermal degradation.