Interfacial properties of glass fiber brittle-ductile dual-matrix composites using micromechanical techniques and acoustic emission

The interfacial adhesion and microfailure modes of glass fiber-reinforced b rittle unsaturated polyester/modified epoxy composites were investigated vi a micromechanical techniques and acoustic emission (AE). Various silane cou pling agents caused different degrees of interfacial adhesion and subsequen t microfailure modes. In the brittle matrix layer, the number of matrix fra gments was significantly influenced by the type of silane coupling agents. The more cracks, the higher the interfacial adhesion under both dry and wet conditions. This is attributed to the chemical and hydrogen bondings in tw o interphases. The results obtained from microdroplet and fragmentation tes ts were correlated by associating with the AE technique. The sequential occ urrence of mainly three groups of AE were as follows: the first group origi nated mainly from brittle matrix cracking. The second and the third groups resulted in fiber breakage and ductile matrix cracking and debonding. For d ual-matrix specimens the micromechanical tests provide reliable information with regard to the interfacial adhesion and characterize the microfailure modes when combined with the AE technique.