Exploring Network Formation of Tough and Biocompatible Thiol‐yne Based Photopolymers

Abstract

This work deals with the in-depth investigation of thiol-yne based network formation and its effect on thermomechanical properties and impact strength. The results show that the bifunctional alkyne monomer di(but-1-yne-4-yl)carbonate (DBC) provides significantly lower cytotoxicity than the comparable acrylate, 1,4-butanediol diacrylate (BDA). Real-time near infrared photorheology measurements reveal that gel formation is shifted to higher conversions for DBC/thiol resins leading to lower shrinkage stress and higher overall monomer conversion than BDA. Glass transition temperature (T ), shrinkage stress, as well as network density determined by double quantum solid state NMR, increase proportionally with the thiol functionality. Most importantly, highly cross-linked DBC/dipentaerythritol hexa(3-mercaptopropionate) networks (T ≈ 61 °C) provide a 5.3 times higher impact strength than BDA, which is explained by the unique network homogeneity of thiol-yne photopolymers.

Enhanced reduction of polymerization-induced shrinkage stress via combination of radical ring opening and addition fragmentation chain transfer

“…16 Moreover, VCPs bearing urethane groups lead to exceptionally low values of shrinkage stress. 13 Another well-established approach to counteract polymerization-induced shrinkage stress are thiol-ene 17 or thiol-yne 18,19 systems. They undergo an alternating chain transfer mechanism, which leads to a shift of the gelation toward higher conversions and as a result to a reduction of the polymerizationinduced shrinkage stress.…”

Investigating Photocurable Thiol‐Yne Resins for Biomedical Materials

“…Although DBC showed low monomer cytotoxicity in previous studies, the toxicity of photoinitiators or their cleavage products must not be neglected . Consequently, the migration behavior of the alkyne functionalized PI Irg 2959mod was studied and compared to its nonderivatized reference Irg 2959.…”

3D Laser Micro‐ and Nanoprinting: Challenges for Chemistry

“…Although some materials or polymers are not biocompatible or cause mutations, usually only the monomer is toxic, for example, bisphenol A, but after cross‐linking, cells are viable on these materials. Unfortunately, most studies describing novel photoresists for biological applications only report the biocompatibility of the printed material in short‐term assays (1–2 days of cell culture) . However, several weeks of cell culture are, for example, necessary to study stem‐cell differentiation in 3D scaffolds …”