Polyurethane nanocomposites with click-coupled nanodiamonds exhibiting enhanced mechanical and shape memory effects

Abstract

Poly(&#603

-caprolactone)diol (PCL)&#8211

functionalized nanodiamonds (f-NDs) were synthesized using a click chemistry reaction between the azide-moiety PCL and alkyne-moiety NDs and were incorporated into shape memory polyurethane (PU) at f-ND concentrations of 0, 0.5, 1, and 2 wt % to produce high-performance shape memory nanocomposites. The PU/f-ND nanocomposites exhibited better shape recovery, shape recovery stress, and breaking stresses than pure PU. Shape recovery of greater than 95% was demonstrated for all the nanocomposites in the third cycle, and the shape recovery stresses increased significantly with the f-ND content. These enhanced mechanical and shape recovery properties are ascribed to increased interactions between the f-NDs and PU matrix due to incorporation of click-coupled f-NDs. The click-coupled NDs can be used as nanofillers to enhance the mechanical and shape memory properties of polymers.