(517d) Molecular Influence On Segmental Dynamics of Select Model Poly(urethane urea) Elastomers

Segmental dynamics in a series of 4,4’-dicyclohexylmethane diisocyanate- diethyltoulenediamine-poly(tetramethylene oxide) based poly(urethane urea) (PUU) elastomers have been investigated. Scale-bridging of segmental dynamics determination was accomplished through a well-coupled multiscale characterization and multiscale modelling approach. New experimental observations obtained by dielectric analysis and solid-state nuclear magnetic resonance (NMR) not only clearly elucidate the key material attributes that are critical to a material’s response at the moment of target interaction with either accelerating projectile or other stress wave excitation, but also serve to provide validation with respect to high strain-rate deformation results from simulation. Solid-state NMR results further reveal the molecular dynamics associated with respective hard segment and soft segment domains, as well as with various phase mixed regions, thus allowing for better corroboration with microstructure details discerned from atomic force microscopy analysis as well as for enabling synthesis of hierarchical PUU elastomers with desired dynamic deformation response to provide enhanced protection under extreme dynamic environments.