Networks from highly crosslinked polymer combs

Abstract Comb polymers are branched macromolecules used as compatibilizers, surface modifiers, and, when polymerized, as strong networks. Comb polymers are typically synthesized to contain different backbone and sidechain chemistries, which can result in multifunctional reactivity and strong phase separation between different polymer domains. Here, we explore the design of comb polymers that could result in high-modulus, tough networks by synthesizing polymers with glycidyl methacrylate sidechains capable of participating in dense crosslinking reactions. We synthesized several comb polymers containing homopolymer, block, or random copolymer sidechains, and compared their mechanical properties and network structures with those of their linear counterparts. Comb polymers with random copolymer side chains had superior toughness, even compared with their linear counterparts. We hypothesize that the statistical distribution of monomers along the grafts breaks up crosslinking sites, disfavoring intramolecular crosslinks and favoring intermolecular crosslinks. We expect these polymers to be useful for multifunctional coatings and as adhesives with high modulus and toughness.