Fabrication of graphene oxide and hyperbranched polyurethane composite via in situ polymerization with improved mechanical and dielectric properties

Herein, we report a simple and one‐pot route for the synthesis of graphene oxide (GO)/hyperbranched polyurethane (HBPU) composite by in situ polymerization technique. The polyurethane (PU) chains formed covalent linkages with the exposed hydroxyl and carboxylic acid groups on the GO. The composite was characterized by optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, and infrared (IR) spectroscopy. The characterization results revealed that the GO sheets were well dispersed within the HBPU matrix, resulting in very good enhancement in tensile strength and Young's modulus of the composites. Differential scanning calorimetry (DSC) suggests that the GO has a nucleating effect for the HBPU. The composites also show a mild increase in stability towards thermal degradation, and significantly, higher dielectric constant compared with neat HBPU at low frequencies. POLYM. COMPOS., 39:2765–2770, 2018. © 2017 Society of Plastics Engineers