Mechanical Property Modification of “Living” Networks via PET‐RAFT Photopolymerization

Abstract

Abstract“Living” polymer networks have the ability to grow in size and mass after initial polymerization through the insertion of new monomers. In this work, a one‐pot method is used to prepare “living” polymer networks and modify their mechanical properties via the photo‐electron/energy transfer reversible addition‐fragmentation chain transfer (PET‐RAFT) photopolymerization method. The “living” networks are made from company‐bought constituents (N,N‐dimethylacrylamide [DMAm] monomer and poly(ethylene glycol) diacrylate [PEGDA] 700 crosslinker) so that no synthesis is involved. The study uses two different RAFT agents: asymmetric 2‐(n‐butyltrithiocarbonate) propionic acid (BTPA) and symmetric S,S‐dibenzyl trithiocarbonate (DBTTC). The study then modifies these parent networks with three monomers (acrylamide [AAm], DMAm, and methyl acrylate [MA]) by recommencing the PET‐RAFT process. Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) are conducted on the “living” networks to investigate the effects of monomer insertion after photo‐growth. The networks are also subjected to compression testing, where the daughter networks display modified mechanical properties dependent on both the choice of monomer and RAFT agent symmetry.