Thermoplastic nylon powder with a low melting point was added to Biphenyl Epoxy to serve as a forming stress release agent that is intended to reduce the stress resulting from Epoxy Molding Compound (EMC). The purpose of this study was to explore the physical impact and effect on the formed object after adding nylon powder to Biphenyl Epoxy. Mechanical properties were explored through the Izod impact test and the three-point bending test. Thermal Mechanical Analysis and Dynamic Mechanical Analysis were conducted to probe the coefficient of thermal expansion (CTE) and the glass transition temperature (T-g). The rate of water absorption was measured via a test of the pressure cook test (PCT), and insulation resistance was assessed through the insulating destruction experiment. The results indicate that adding nylon powder increases the fracture energy of the epoxy-formed material; however, mechanical properties decreased slightly. TMA showed that the CTE (alpha(1)) decreased when nylon was added, and DMA revealed that heat resistance decreased slightly. The water absorption rate test and the PCT test showed that the rate of water absorption increased to a small extent, whereas the breakdown voltage (BDV) decreased slightly. (C) 2003 Wiley Periodicals, Inc.