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 thermopla stic 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 modifi ed systems were calculated using isothermal and dynamic thermogravimetric m ethods. The results have shown good agreement between the activation energi es obtained from all methods if it is assumed that the mechanism of degrada tion of these epoxy resins is of sigmoidal type. The mechanical behavior wa s studied by stress-strain tests. The tensile properties of the blends were measured at different test temperatures. In general, the toughness improve d when the test temperature increased. The more effective thermoplastic mod ification was the blend with 10 phr ABS, because it obtained better mechani cal data than the other ones at low test temperatures. The fractography study proved that the blend with 10 phr ABS had the satisf actory morphology in order to get a toughness improvement, but the SEM micr ographs also displayed adhesion problems between ABS particles and the epox y matrix which did not allow the mechanical behavior improvement that was e xpected. (C) 2001 Elsevier Science Ltd. All rights reserved.