Mechanical properties and fracture mechanisms of fiber reinforced PBT/PC/elastomer blends

A group of glass fiber (GF) reinforced polymer blends with controlled morphology were designed and prepared by sequential compounding of a poly(butylene terephthalate)/GF (PBT/GF) composite with an reactive elastomer (IDB) and/or polycarbonate (PC). It was shown that both the (PBT/GF)IPC and (PBT/GF)/IDB composites has a decreased tensile strength, Young's modulus and impact strength, when compared with the PBT/GF composite. However, when the (PBT/GF), PC and IDB were compounded together, a remarkable increase in impact strength was achieved. Microscopic study indicated that the (PBT/GF)/PC/IDB composite fractured in a ductile failure mode at the interphase between the "PBT-sheath" on the GF and the PBT/PC/IDB matrix. Toughening mechanisms for the composite were discussed.