Degradable Bioelastomers Prepared by a Facile Melt Polycondensation of Citric Acid and Polycaprolactone-diol

Abstract

Citrate-based bioelastomers have great potentials in various biomedical fields. An appropriate selection of diol monomers could tune their properties to fulfill different application requirements. Herein, polycaprolacone diol (PCL-diol) was selected as the diol monomer to fabricate poly(caprolactone-diol citrate) (PCC) degradable bioelastomers by a one pot melt polycondensation coupled with subsequent thermosetting or post-polymerization. The catalyst-free polycondensation reaction was confirmed by Fourier transform infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (1HNMR) spectroscopy. The properties of the PCC elastomers were explored by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), uniaxial tension tests, dynamics mechanical analysis (DMA), water-contact angle and in-vitro degradation measurements. The results showed that the molar ratio of monomers and thermosetting conditions had significant effects on the ultimate properties of the PCC elastomer. By regulating monomer ratio and thermosetting temperature the crosslink density ranged from 32 ± 6 mol/m3 to 292 ± 18 mol/m3, the tensile strength ranged from 171 ± 28 KPa to 977 ± 112 KPa, Young’s modulus ranged from 252 ± 36 KPa to 1737 ± 212 KPa, ultimate elongation ranged from 70 ± 9% to 260 ± 32%, the static-water-contact-angle was in the range of 65.4 ± 1.8 ∼ 91.0 ± 0.9° and the weight loss of the PCC elastomer in phosphate buffered saline (PBS) (pH =7.4) was in the range of 30 ∼ 100 wt% after 8 weeks degradation. An elastic and compressible, porous scaffold was fabricated via a salt leaching method, which has potential use in soft tissue grafts.