An Investigation On Tribological Properties Of Poly (Vinylidene Fluoride)(PVDF) And Its Nanocomposites

As one of the most important fluoropolymers,PVDF has been widely used in a number of applications.But little attention has been paid to potential application in tribological field. In order to improve the tribological properties of PVDF,PVDF/nano-clay, PVDF/nano-PTFE,PVDF/nano-SiC composites were prepared.The tribological behaviors of the nanocomposites against 45# carbon steel ring were evaluated on a block-on-ring type(M-2000) wear tester.Universal testing mechine, Transmission electron microscopy(TEM),Dynamic mechanical analysis(DMA),Thermo gravimetric analysis(TGA),Differential scanning calorimetry(DSC),X-ray diffraction (XRD)and Fourier transform infrared spectroscopy(FTIR) were used to characterize the mechanical properties,dispersion effects,thermal properties and crystallinity properties respectively.Scanning electron microscope(SEM) was used to observe the morphology of worn surface,counterface and wear debris for understanding the wear mechanism.Relative conclusions were summarized as follows:1.The comprehensive performance including tribological properties of PVDF/nano-PTFE composites prepared by the mechanical/twin screw extrusion technique were better than that prepared by the solution-cast technique.2.Effects of the three kinds ofnano-filler are as follows:the friction coefficient and wear rate of PVDF/nano-PTFE composites decreased by 60%and 70%respectively at most; the decrease for PVDF/clay nanocomposites is about 25%at most for both friction coefficent and wear rate;while nano-SiC has little possitive effect for the tribological properties of PVDF.3.Nano-PTFE can reduce the friction coefficient,so that inhibit the temperature rise during sliding and so reduce the plastic deformation of the composites,so wear rate decreased as nano-PTFE content increased.While at the same time,the formation of transfer film and wear debris adhered to the worn surface caused by the nano-PTFE act as lubricating elements also reduce friction coefficient and wear rate.Lower content of nano-clay can improve the tribological of the materials,which may be due to the crystal form of PVDF transform fromα-toβ-form.