Development of fiber glass-renforced benzoxazne/epoxy copolymers for print circuit board (PCB'S)

Abstract

Bisphenol-A based benzoxzine resin was copolymerized with novolac epoxy resin in order to study the effect of composition ratio on processing behaviors, thermophysical properties of the resulting copolymers. The copolymers were further reinforced with glass fiber (E-glass) and were characterized for an application as printed circuit boards (PCB s). Rheometer was used to determine the processing window of the resin mixtures. The liquefying point and gel point to liquid of the resin mixtures increased with increasing amount of novolac epoxy while the processing window of the mixtures was found to shift to higher temperature range. Cure behaviors and glass transition temperature of the copolymer were studied using differential scanning calorimeter (DSC) which indicated a single exothermic curing peak at 250℃. The experimental results also revealed that the curing temperature of the copolymers shifted to higher value as the fraction of the novolac epoxy in the resin mixtures increased. Thermal and mechanical properties were found to systematic increase with novolac epoxy composition. The fiber glass-reinforced with about 80% by weight of glass fiber. The reinforced matrix systems show that the better in flexural properties and the thermal expansion behavior of fiber glassreinforced polybenzoxazine and epoxy copolymers specimens was measured from 30 to 120℃ indicated that the coefficient thermal expansion was reduced from 46.8 ppm/℃ to 24.26 ppm/℃.