Thiol-acrylate copolymers are disclosed that are useful, for example, as injectable biomaterials to provide both mechanical support and biological cues to stimulate bone regrowth. Composites can be formed, for example incorporating hydroxyapatite crystal inclusions into the copolymer. In one embodiment, the composite is gas-foamed with a blowing agent during or before cure to form a porous, interconnected scaffold. The synthesis employs an amine-catalyzed Michael addition co-polymerization of a poly-thiol with a poly-acrylate. The catalyst is an in situ catalyst, such as a tertiary amine moiety that is covalently bonded to one of the reactants, preferably to the poly-acrylate. The materials can rapidly co-polymerize in vivo or in vitro via catalysis by the “attached” in situ tertiary amine groups.
