Redox and thiol–ene cross-linking of mercapto poly(ε-caprolactone) for the preparation of reversible degradable elastomeric materials

A novel thiol-functionalized PCL (PCL-HDT) was synthesized following a convenient two-step procedure. Taking advantage of the pendant thiol group, degradable elastomeric materials have been prepared from PCL-HDT by redox or thiol–ene reaction. Elastomers were characterized by HRMAS NMR spectroscopy to confirm the formation of disulfide or thioether cross-links. The thermal and mechanical properties of elastomers have been assessed by DSC, DMA and tensile tests. Disulfide containing elastomers (EMSS) and thioether containing elastomers (EMTE) exhibited improved mechanical properties with ultimate strains up to 220%. The stability of the mechanical properties at temperatures close to body temperature was confirmed by DMA with G′ ≈ 200 MPa and G′′ ≈ 15 MPa. Finally, the reversibility of the disulfide formation and breaking has been evaluated, and confirmed the potential of these degradable elastomers as biomaterials.