An investigation on the effect of polyvinyl butyral interlayer forms on the fracture toughness of glass reinforced phenolic laminates

In the recent years, thermoplastic interlayers are employed to improve the fracture toughness of laminated composites. In this research, PolyvinylButyral (PVB) was utilized as a flexible thermoplastic interlayer in forms of electrospun nanoweb, solution, film and powder to evaluate the effect on interlayer shape on the fracture toughness of glass-phenolic laminates. DCB and ENF tests were conducted to study the fracture toughness under modes I and II conditions. Among all the specimens, those modified with 30 μm electrospun PVB, with 60% increase in the mode II fracture toughness, showed the highest performance. Those consist of PVB solution (3 phr), with an increase of 50% in mode I fracture toughness, ranked the second. In the mode II fracture toughness test, for the specimens modified with the nanoweb, solution and film interlayers, and the value of GIIc increased by 38%, 24% and 18%, respectively. Samples containing PVB powder showed a decrease of 22% in the property. •PVB thermoplastic for using as interlaminar composite reinforcement.•Appling nanofibers, microfilm, solution, and powder as interlaminar toughener on phenolic composites by autoclave process.•The effect of thickness of PVB interlayer on fracture toughness of phenolic composites under mode I and Mode II loading.