Effect of rapid curing doped epoxy adhesive between two polycarbonate substrates on the bond tensile strength

摘要

The aim of this work was to determine the bond tensile strength of a polycarbonate sandwich joined with a fast cured epoxy adhesive. A 6.5 kW single mode microwave unit operating at 2.5 GHz was used to fast cure the epoxy adhesive. The samples ofpolycarbonate were prepared in accordance with ASTM D2095-72 (modified) and glued with a two-part epoxy adhesive mix employing a doping agent for rapid cure in the microwave unit. Two operational parameters, cure time, microwave power and one processingparameter, dopant concentration, were varied to determine their effect on the resulting bond strength. These rapidly-cured samples were then tensile tested to determine the joint strength as a function of the operational and processing parameters. Thefracture surfaces of the adhesively joined polycarbonate samples were examined using light microscopy and scanning electron microscopy. A polariscope was employed to determine the variation in stress in the adhesive joint. Conventional curing of epoxyadhesive polycarbonate sandwiches was also undertaken. The tensile strength of these conventionally-cured bonded samples were then compared to that of fast cure using microwave. Results of the processing and testing program indicate the effect of dopantconcentration, curing time and microwave absorbed power on the resulting mechanical strength of the adhesively bonded joint.