Functional Nanogels as a Route to Interpenetrating Polymer Networks with Improved Mechanical Properties

Interpenetrating polymer networks (IPNs) were prepared from dual-network formation wherein one of the orthogonal networks was derived from the pre-formed functional nanogels. Nanogels with or without urethane linkages were synthesized via thiol-Michael addition reactions and with less than 100 nm as discrete particles in the bulk state. The acrylate-functionalized nanogels can be dispersed in and swollen by hydroxyl-isocyanate monomers, which upon polymerization by two rapid non-interfering routes achieves 100% conversion for both networks. Homogeneous morphologies of IPNs can be obtained by controlling the loading level of different nanogels. This convenient route to IPNs can provide significantly toughened polymers with good shape memory properties and no compromise in the bulk IPN modulus or strength when incorporating nanogels with urethane linkages.