Bottom-up design toward dynamically robust polyurethane elastomers

Segmented polyurethanes exhibit versatile mechanical properties, where their outstanding resilience and toughness enable material designs with high energy-absorption capability. However, there is a lack of fundamental understanding regarding the underlying molecular pathways toward rapid dissipation of high-pressure fields. Here, we design a set of 4,4'-methylenediphenyldiisocyanate (MDI)-butanediol (BDO)-poly(tetramethylene oxide) (PTMO)-based polyurethanes and elucidate the influence of composition on thermal transition characteristics, crystallinity, segmental dynamics of PTMO, as well as high-strain-rate impact response on the microscale. Furthermore, simulations of shock compression, performed using an isotropic, constant-stress Hugoniostat method, comparing a MDI-BDO-PTMO-based polyurethane with polyethylene models of varying crystallinity suggest that the high-rate mechanical response is dominated by a soft domain response, which in turn can be sensitive to specific interactions present in the PTMO component that are not present in PE.