Thermal decomposition behavior and the mechanical properties of an epoxy/cycloaliphatic amine resin with ABS

A bifunctional epoxy resin was modified with several amounts of a thermoplastic based on a mixture of acrylo-nitrile-butadiene-styrene (ABS) in order to improve the toughness of the resin. Previous to study of the mechanical properties, thermal degradation behavior and the kinetic data of the modified systems were calculated using isothermal and dynamic thermogravimetric methods. The results have shown good agreement between the activation energies obtained from all methods if it is assumed that the mechanism of degradation of these epoxy resins is of sigmoidal type. The mechanical behavior was studied by stress-strain tests. The tensile properties of the blends were measured at different test temperatures. In general, the toughness improved when the test temperature increased. The more effective thermoplastic modification was the blend with 10 phr ABS, because it obtained better mechanical data than the other ones at low test temperatures. The fractography study proved that the blend with 10 phr ABS had the satisfactory morphology in order to get a toughness improvement, but the SEM micrographs also displayed adhesion problems between ABS particles and the epoxy matrix which did not allow the mechanical behavior improvement that was expected. (C) 2001 Elsevier Science Ltd. All rights reserved.