There are a number of important applications and benefits for the type of network rearrangement implemented in photochemical Covalent Adaptable Networks (CAN's). In this study, we focus on CANs -based materials that can be designed to reduce the shrinkage stress that arises during polymerization when weak intermolecular interactions are replaced by covalent bonds. CANs-based networks with different reversible addition-fragmentation termination (RAFT) moities present within the polymer have been shown to reduce the external stresses applied post-polymerization via photo-induced creep with differing efficiencies. The differences in the RAFT-induced rearrangement of the network in a polymer formed by a radical-mediated thiol-ene reactionversus a thiol-ene `click` Michael addition reaction has also been studied and charecterized. Additionally, a mild and efficient synthesis of acrylate functionalized trithiocarbonates and allyl sulfides RAFT monomers is described and their efficiency in photo-stress relaxation during and post polymerization is demonstrated. The RAFT monomers designed in this study have been shown to have highly efficient stress relaxation properties. In post-polymerization relaxation studies of thin films using the trithiocarbonates, stress reduction of up to 55% has been observed whereas in stress reduction observed during polymerization RAFT monomers present within the network at 1.5% by weight was shown to reduce up to 70% of the stress in a traditional dental monomer system.

Advances in covalent adaptable networks: Material property control using novel allyl sulfides and trithiocarbonates

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.