Exploring the tribological properties of PA6/GO nanocomposites produced by in situ polymerization

One of the major challenges in using GO or other nanofiller materials in the polymer matrix is nonhomogeneous dispersion and aggregation. In situ polymerization is promising for obtaining well- dispersed GO-filled polymer nanocomposites and imposing unique friction and wear characteristics. Thus, the tribological properties of PA6/GO nanocomposites produced by in situ polymerization were investigated in this study. To establish whether the in situ polymerization was completed successfully, characterization tests using XRD, XPS, FT-IR, Raman spectroscopy, and AFM were initially carried out. All of the characterization tests indicated convincingly that PA6 was successfully grafted onto GO flakes using in situ polymerization. Next, the thermal properties of the nanocomposites were determined by DSC, TGA and LFA. The nucleation influence of GO resulted in a higher crystallization temperature, and the GO content had a minor effect on Td. The load carrying capacity is investigated by tensile, bending, and impact tests. When compared to PA6, increasing the GO content increased the tensile, flexural, and impact properties. A significant reduction in friction coefficients is achieved with increasing GO weight fraction, and the wear rates at any sliding distance are lower than those of PA6. Furthermore, the friction heat was quickly dissipated by the higher thermal conductivity coefficient, contributing to the lower friction temperatures with increasing GO weight fraction. The PA6/GO nanocomposites formed a continuous and smooth transfer film on the steel counterfaces as the GO content increased. These observations prove the success of in situ polymerization for achieving unique friction and wear characteristics. [GRAPHICS] .