▎ 摘　　要

Polyurethane acrylate (PUA) are widely used as coating for automobile industry. Making these coatings electrically conductive would open up new applications. Using thermally reduced graphene (TRG) and in-situ polymerization we have created PUA nanocomposites with an ultralow percolation concentration of 0.15 wt% (0.07 vol%) graphene. Urethane-acrylate oligomer (UAO) was synthesized and diluted by tri-propyleneglycol diacrylate (TPGDA) to form flowable UAO/TPGDA mixture (UA). TRG was solvent-blended in UA to form uncured TRG/UA liquids and were polymerized by free radical polymerization with azobisisobutyronitrile (AIBN) initiator. Percolation concentrations of polymerized TRG/PUA nanocomposites occurred at 0.15 wt% (0.07 vol%), as determined by surface resistance measurements, bulk electrical conductivity, and modulus. TEM images revealed a homogeneous dispersion of TRG in PUA. Differential scanning calorimetry (DSC) was used to monitor the polymerization of TRG/UA uncured liquids and thermal properties of polymerized TRG/PUA nanocomposites. Polymerization heat, glass transition temperature, and polymerization temperature are independent of TRG loading, though polymerization temperature is similar to 10 degrees C lower in the absence of TRG. (C) 2012 Elsevier Ltd. All rights reserved.