A study of glass fiber–epoxy composite interfaces

Abstract Fourier transform infrared spectroscopy was utilized to characterize the interfacial bonding in glass‐fiber‐reinforced composites. The pH of the treating solution significantly affects the interfacial chemical bonding. The natural pH of the solution gives the maximum interfacial bonding. The decrease of the interfacial bonding is due to the side reactions that occur when NaOH or HCl is added to the solution. The temperature of the curing process has little effect on the amount of the interfacial chemical bonding. We attribute this to the reaction rate constant of the interfacial reaction being much larger than that of the epoxy polymerization. From the hygrothermal behavior, we have found the amount of silane needed for hygrothermal condition is different from that for dry condition.