Electrochemical Impedance Spectroscopy Study of the Ultraviolet Exposure of Ballistic Resistant Polymer Matrix Composites

This study examined the effect of ultraviolet radiation on ballistic resistant polymer matrix composites. Two composite systems studied included a phenolic matrix with either S2 Glass? or Kevlar? fiber laminates. These composites were weathered in ultraviolet conditions and the effects were quantified with multiple destructive and non-destructive testing. Electrochemical impedance spectroscopy (EIS) was used as a non-destructive evaluation method which is a commonly used experiment in the corrosion community. Circuit modeling the EIS spectra produced both resistive and capacitive characteristics inherent of the composite materials. Surface characterization was performed to determine if degradation was occurring at the composite surface. Techniques included: color, gloss, surface profilometry, and water contact angle. Tensile and flexural destructive experimentation revealed the influence of the ultraviolet exposure on the mechanical properties. It was determined that the resistive portion of the EIS response correlated well with the ultimate tensile strength of the S2 Glass? fiber composites.Army Research Laborator