Ballistic impact resistance of thermoplastic composites

Correlation between adhesive strength, stiffness, flexural properties and ballistic impact resistance of Kevlar-KM2 composites with polysulfone (PSU) resin matrix was studied through examining the failure of the composites on different processing conditions. Processing temperature greatly changed resin molecular conformation. Resin molecular conformation directly influenced composite flexural properties as well as ballistic impact energy absorption. Composites processed at 260 degreesC showed significantly higher ballistic impact resistance than composites processed at 350 degreesC. Significantly different failure mechanisms of these composites that are induced by different processing conditions are considered to be responsible for this result. The former exhibited mainly tension mode of failure whereas the later failed mainly shear cut. Fiber straining accompanied with delamination due to the tension mode of failure is preferred failure mechanism for better ballistic impact energy absorption.