Sequential graft-Interpenetrating polymer networks based on polyurethane and acrylic/ester copolymers

Abstract

Highly transparent and tough graft-interpenetrating polymer networks (graft-IPNs) were synthesized using an elastomeric polyurethane phase (PU) and a highly stiff acrylate-base copolymer phase. The grafting points between the two networks were generated with the purpose of minimizing the phase separation process of the polymeric systems. In order to generate the grafting between the networks, an acrylic resin capable of undergoing both free radical and poly-addition polymerization was employed. The thermo-mechanical properties, fracture toughness properties as well as network and surface phase morphology of the graft-IPNs synthesized were evaluated in this work. Data obtained suggested that the minimization of the phase separation was achieved by the generation of crosslinking points between both networks. High transparency was obtained in all samples as an indication of the high level of interpenetration achieved. The relative high values obtained for the fracture toughness tests coupled with the high transparency achieved suggest that generating chemical crosslinks between networks is a good approach for diminishing the phase separation process in the systems increasing the compatibility between the networks.