Investigating the Thermal and Mechanical Properties of Polyurethane Urea Nanocomposites for Subsea Applications

Commercial applications of polymer nanocomposites for materials used in offshore settings is continuously touted as a potential solution to expand the material property envelope of polymers used in high pressure and temperature environments. In this regard, polyurethane urea (PUU) has been successfully used in such environments, however, they are limited in terms of their ability to offer multifunctional behavior i.e., thermal conductive behavior with mechanical properties. This gap offers the opportunity for their properties to be enhanced as an advanced multi-functional polymer. Hence, in this study, polyurethane urea/graphene nanocomposites were synthesized using commercial Polyurethane urea (Task 12), and graphene nanoplatelets (GnP). The graphene nanoplatelets were dispersed in one part of the polyurethane urea component using facile dispersion methods. The properties of the new PUU nanocomposite materials were studied using SEM, mechanical and thermal analysis techniques (DMA and Hot Disk), to examine the development of the multifunctional properties in the PUU nanocomposite. Our analysis describes the influence of graphene nanoplatelets at ultra-low concentrations on multi-functional properties of the PUU nanocomposites. The developed nanocomposites recorded a 16% increase in the tensile strength and an 8% increase in the thermal conductive values. The property improvements are credited generally to the high aspect ratio of graphene nanoplatelets, dispersion and filler-polyurethane interactions at the interface. The impartation of multi-functional behavior, in enhancing the thermal conductivity whilst maintaining the mechanical properties makes it a potentially valuable for subsea applications.