Molecular influence on dynamic stiffening of synthetic polyurethanes through laser-induced supersonic microscale impact tests

POSTER

Abstract

High-strain-rate response is an important characteristic of protective elastomers. To discern the molecular influences on dynamic stiffening in polyurethane (PU), we synthesized two-component PUs from poly(tetramethylene oxide) (PTMO) and either hexamethylenediisocyanate (HDI) or 4,4’-methylenediphenyldiisocyanate (MDI). From dynamic mechanical analysis, HDI-PU displays semicrystallinity while MDI-PU appears amorphous. We also synthesized three-component PUs with the chain extender butanediol (BD) to introduce segmented hard domains. We performed supersonic microscale impacts with a laser-induced particle impact test in which a silica microsphere is accelerated up to ~1000 m/s. The impact is recorded with micron spatial resolution and nanosecond temporal resolution on an ultra-high-speed camera. In a velocity range of 50 to 1000 m/s, we show that MDI-PU exhibits greater dynamic stiffening than HDI-PU. We hypothesize that greater intermolecular hydrogen bonding in MDI-PU plays an important role. Finally, we discuss the role of segmented hard domains in dynamic stiffening of polyurethanes.

Presenters

  • Yuchen Sun

    Massachusetts Institute of Technology, Chemistry, MIT

Authors

  • Yuchen Sun

    Massachusetts Institute of Technology, Chemistry, MIT

  • David Veysset

    Massachusetts Institute of Technology, Institute for Soldier Nanotechnologies, MIT

  • You-Chi Mason Wu

    Chemistry, MIT

  • Alex J Hsieh

    US Army Research Laboratory, U.S. Army Research Laboratory, US Army Research Laboratory, RDRL-WMM-G

  • Steven E Kooi

    Massachusetts Institute of Technology, Institute for Soldier Nanotechnologies, MIT

  • A A Maznev

    Chemistry, MIT

  • Jan W Andzelm

    US Army Research Laboratory, RDRL-WMM-G

  • Timothy M Swager

    Department of Chemistry, Massachusetts Institute of Technology, Chemistry, MIT

  • Keith Adam Nelson

    Massachusetts Institute of Technology, Department of Chemistry, Massachusetts Institute of Technology, Chemistry, MIT, MiT, Cambridge, MA 02139