POLYSILOXANE MODIFIED EPOXY POLYMER NETWORKS .1. GRAFT INTERPENETRATING POLYMERIC NETWORKS

Graft interpenetrating polymeric networks of epoxy resin and polydimet hylsiloxane (PDMS) were synthesized using 3-aminopropyltrimethoxysilan e (gamma-APS) as coupling agent. The dynamic mechanical analysis shows partially mutual compatibility between these two thermodynamically im miscible polymers. Due to the inappropriate domain size and the poor c ohesive properties between epoxy resin and PDMS domain, the fracture e nergy (G(IC)) decreased drastically at low PDMS content (5%). While th e PDMS domain size increased according to the PDMS contents, the fract ure energy was then improved. This experimental result indicates that PDMS with an appropriate domain size can be used as a toughness modifi er for polyfunctional epoxy resins. (C) 1997 Elsevier Science Ltd.