Sequential Graft-Interpenetrating Polymer Networks of Polyurethane and Acrylic/Vinyl Ester Based Copolymers

摘要

In recent decades, a fast growing branch in the field of polymers has attracted the attention of the public and safety industry due to its promising results. Interpenetrated polymer networks (IPN), which are composed of two or more different polymer networks held together by their mutual entanglements, seek to combine the best properties of the networks in order to achieve a material with better properties compare to their not-interpenetrated counterparts (1, 2, 3). There has been an increasing interest in developing IPNs in which the two networks are chemically cross-linked. These chemically cross-linked IPNs also known as graft-IPNs, possess remarkable mechanical properties. The enhancement in their mechanical properties can be attributed to the cross-linking of the networks (4). The graft-IPNs synthesized in this study consisted of an acrylated based copolymer phase, also known as the stiff phase, which provides the strength, and a high impact-absorbing PU phase. The copolymer phase was synthetized using methyl methacrylate (MMA) with the inclusion of the vinyl ester, bisphenol A-glycidyl methacrylate (BisGMA), and the polyurethane phase was synthetized using two diols: 1,1,1-tris(hydroxymethyl) propane (TRIOL) and poly(tetramethylene ether) glycol (PTMG) average Mn ～ 650 g mol~(-1). The effect in the thermo-mechanical properties was assessed by dynamic mechanical analysis, following the change in the storage modulus (E’) and tan ? of the samples, and quasi-static fracture tests to determine the critical-stress-intensity factor, KIc. Graft-IPNs showed increasing values of storage modulus and tan as the percentage of copolymer increased in the samples.