Characterization of Graphene/H-BNNS Reinforced High-Performance Polyurethane Nanocomposites Produced Using Solvent Casting Method

Abstract

Polyurethane (PU) is a popular material for nanocomposites application in polymer science and technology. In pure form, PU is not suitable for engineering applications that require additional processing to improve the mechanical and thermal properties. High-performance PU nanocomposites with superior properties may be obtained by reinforcement with nanostructures such as graphene (Gr) and hexagonal boron nitride nanosheets (h-BNNS). In the present research, h-BNNS and Gr are used as a reinforcement into the PU matrix. Solvent casting method has been used to obtain PU/Gr, PU/h-BNNS, and PU/Gr + h-BNNS (hybrid) nanocomposites. Gr and h-BNNS are reinforced into the PU matrix at weight % (wt.%) of 0.3, 0.5, and 0.7, respectively. In hybrid PU nanocomposite the combination of both Gr and h-BNNS has been used in the wt.% of 0.3, 0.5, and 0.7. Characterization techniques such as Fourier transform infrared spectrometer (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and dynamic mechanical analysis (DMA) were employed to elucidate the morphological and structural changes within the PU nanocomposite matrix. Results revealed the establishment of polymerization in all three types of reinforcement and the presence of hard segments in the h-BNNS reinforced PU nanocomposites, which indicates the presence of hydrogen bonding. h-BNNS reinforced PU nanocomposites revealed the formation of strong interfacial interaction between the h-BNNS and the PU matrix. Significant changes in the storage modulus (E') were observed with the various types of reinforcing agents. Reinforcement of 0.5 wt.% of h-BNNS yields better results compared to Gr and hybrid reinforcement.