Pultruded fibre-reinforced PMMA/PU IPN composites: Processability and mechanical properties

This paper presents a proprietary process developed to manufacture poly(methyl methacrylate) (PMMA)/polyurethane (PU) interpenetrating polymer network (IPN) pultruded composites. The IPN prepolymer was prepared from blends of MMA prepolymer and blocked NCO-terminated PU prepolymer. The processability, mechanical and dynamic mechanical properties of glass fibre-reinforced PMMA/PU IPN composites have been studied. From the investigation of the pot life of the resin, the reactivity of the resin and fibre wet-out, it was found that the PMMA/PU IPN shows excellent processability for pultrusion. Results show that the tan delta of the IPN composite shifts to a higher temperature with increasing PMMA content and that the dynamic shear storage modulus (G') increases with PMMA content. The flexural strength, flexural modulus and hardness of IPN composites increase with PMMA content. However, the impact strength and swelling ratio of IPN composites decrease with increasing PMMA content. Copyright (C) 1996 Elsevier Science Limited.