ABSTRACT
In this paper, the preparation of graphene oxide was achieved by Hummers method and the surface
modification was achieved by poly(hexaneditiol), which was a synthetic thermotropic liquid
crystalline polymer. The c-PHDT/GO/PF composites were prepared by blending, rolling and compression
molding techniques. Then, the as-prepared samples were characterized by FTIR, Raman,
XRD, TGA and POM to obtain information on their structures and properties. After that, the effects
of c-PHDT/GO content on the mechanical properties, friction performance and dynamic mechanical
performance of c-PHDT/GO/PF composites were studied by Mechanical and Dynamic Mechanical
Analysis (DMA) methods. Also, Scanning Electron Microscope (SEM) was used for the characterization
of wear and fracture surface morphology. The results revealed that the reinforcing effect
of c-PHDT/GO was significant as a considerable enhancement on the mechanical performance
of c-PHDT/GO/PF composite as compared to pure phenol-formaldehyde composites was observed:
the impact strength, bending modulus and bending strength increased from 1.63 kJ/m2, 8.61 GPa
and 41.55 MPa to 2.31 kJ/m2, 10.16 GPa and 54.40 MPa respectively at the c-PHDT/GO content =
0.75%. Moreover, the initial storage modulus increased by 28.4%, while the wear mass loss decreased
by 17.8%. More importantly, the reinforcement by c-PHDT/GO was further enhanced as
compared to GO/PF and p-PHDT/GO/PF composites, the impact strength of c-PHDT/GO/PF composite
increased by 27.6% and 11.1%, the bending strength increased by 11.8% and 7.6%, the initial
storage modulus increased by 16.2% and 4.2% and the mass loss due to wear decreased by
12.7% and 8.8%, respectively. Based on these results, we can conclude that the surface modification
of GO by poly(hexanedithiol), which includes synergistic effect by c-PHDT and GO, improves
the interfacial adhesion between GO and the resin matrix, thus reinforcing the composites.