Broadband dielectric spectroscopy and small-angle neutron scattering investigations of polyurethane–graphene foams

This work focuses on dielectric measurements and small-angle neutron scattering (SANS) analysis of polyurethane–graphene nanocomposite that is conducting and of low density. In this research graphene nanoplatelets were used. Polyurethane and graphene were mixed in appropriate weight proportions to make polyurethane–graphene (PU–graphene) nanocomposites. The porosity is decreased with an increase in graphene concentration. The dielectric characteristics such as dielectric constant, dielectric loss, loss tangent, and electric modulus were influenced by the graphene concentration. The conductivity (S/cm) increased rapidly by (~ 4 × 10⁹ times) when the graphene concentration was increased to 30% and it indicates the formation of conducting pathways at high concentrations of graphene. SANS analysis showed that polyurethane has micellar structure and graphene assembles as fractals in the foams leading to conduction pathways in the nanocomposites. This research could benefit creation of lightweight materials for electronics.