Preparation and properties of acid-treated CNT/waterborne polyurethane nanocomposites

Water -borne polyurethane was synthesized by a poly addition reaction with TDI,PTMEG,DMPA and TEA. The aqueous polyurethane dispersioins with three different weight fractions of 30,40 and 50wt.%were prepared . All the dispersions made with whese concentrations showed newtonian behavior. multi walled carbon nanotubes were functionalized using a mixture of sulfuric and nitric acid at a ratio of 3:1.functionalized multi-walled carbon nanotubes were added to these dispersions in two different loads of 0.1 and 0.5 wt.%. the UV/Vis spectroscopy proved the formation of stable suspensions due to the application of ultrasonic agitation on the suspensions . the rheology f such suspension was characterized using the dynamic and steady state measurements. the higher amount of CNT in the suspension imparts non-newtonian and complex viscoelastic behavior. this was attributed to a physical network formed due the prisence of functionalized carbon nanotubes . the cox -merz was not observed for these suspensions.