Effects of Solvent Exposure on Material Properties and Impact Performance of an American Football Helmet Outer Shell Material

The pursuit to maintain the initial performance standard of American football helmets has prompted the implementation of a certified reconditioning and recertification process. Thus, the purpose of this study is to: (i) develop a method to replicate solvent exposure during the reconditioning painting process, (ii) compare selected solvent exposure intensities, and (iii) quantify shifts in material and impact properties of an American football helmet outer shell material. Spraying yielded uniformly exposed samples and was substantiated for investigation of solvent effects. Exposures of n-Butyl acetate to the helmet-grade material surface led to shifts in colorimetric, dimensional, thermal, and tensile properties. Impact performance of helmet surrogate systems performed equivalently. Overall, results substantiated spraying as representative of the reconditioning process and demonstrated shifts in material properties via solvent-induced degradation of helmet-grade outer shell materials.