Thiol‐Mediated Chain Transfer as a Tool to Improve the Toughness of Acrylate Photo‐Crosslinked Poly(ε‐caprolactone)

Abstract

Herein, a straightforward approach is reported to obtain photo-crosslinked, bioresorbable poly(𝝐-caprolactone) (PCL) based networks covering a range of mechanical properties (elongation at break from 203 ± 53 up to 707 ± 101% and ultimate strength from 6.8 ± 2.2 to 13.9 ± 1.5 MPa) via alteration of the network topology. Exploiting multifunctional thiols for crosslinking of acrylate-terminated PCL is an effective method to alter the mechanical properties of photo-crosslinked networks due to the chain transferring ability of the thiols. By controlling the thiol to acrylate ratio, the Young's modulus, elongation at break and ultimate strength can be significantly altered. The materials described in this work can be considered potential candidates for light-based 3D-printing and to serve tissue engineering applications.

Tough Photo-Cross-Linked PCL-Hydroxyapatite Composites for Bone Tissue Engineering

“…In order to overcome this drawback, thiol–acrylate binary cross-linking has been applied to PCL-based networks, which has been reported to result in a significant improvement in the toughness of said networks. − This effect is attributed to the shift in the polymerization mechanism. More precisely, the chain-growth polymerization is shifted toward a combination of step- and chain-growth polymerization, thereby resulting in a more homogeneous distribution of the cross-links.…”