Kevlar™ fiber-reinforced polybenzoxazine alloys for ballistic impact applications

Abstract

A light weight ballistic composites from Kevlar™-reinforcing fiber having polybenzoxazine (BA)/urethane prepolymer (PU) alloys as a matrix were investigated in this work. The effect of alloy compositions on the ballistic composite properties was determined. The increase of the elastomeric PU content in the BA/PU alloy resulted in samples with tougher characteristics; the storage modulus of the Kevlar™-reinforced BA/PU composites increased with increasing the mass fraction of polybenzoxazine. A ballistic impact test was also performed on the Kevlar™-reinforced BA/PU composites using a 9 mm handgun and it was found that the optimal composition of BA/PU alloys should be approximately 20wt% of PU. The extent of the delaminated area and interfacial fracture were observed to change with the varied compositions of the matrix alloys. The appropriate thickness of Kevlar™-reinforced 80/20 BA/PU composite panel was 30 plies and 50 plies to resist the penetration from the ballistic impact equivalent to levels II-A and III-A of NIJ standard. The arrangement of composite panels with the higher stiffness panel at the front side also showed the best efficiency ballistic penetration resistance.