The use of solid-state nuclear magnetic resonance (ssNMR) spectroscopy as a technique for probing and interpretation of the molecular dynamics in select ultrahigh molecular weight poly(ethylene) (UHMWPE) fibers based prepreg materials is investigated. In particular, ssNMR is used to differentiate the influence of molecular dynamics associated with matrix elastomers. Polyurethane and Kraton (R) based elastomers are used in commercial UHMWPE prepregs. The H-1 wideline spectra clearly revealed greater mobility associated with the molecular dynamics of Kraton (R) elastomers than that of polyurethane; this is consistent when comparing prepregs from different manufacturers. These observations corroborate well with the extent of back face deformation in UHMWPE composites when engaged by projectiles, where polyurethane matrix elastomers exhibit greater resistance. Select bulk elastomers were also considered to highlight the dynamic stiffening characteristics associated with matrix elastomers, where results further substantiate the importance of the molecular attributes on the overall dynamic deformation response in these composites. Published by Elsevier Ltd.