| Epoxy resin（EP）has been used widely in civilian products in the military industry and aerospace field due to its excellent chemical and temperature resistance,low creep,high tensile strength and modulus,low cure shrinkage,etc.However,the three-dimensional cross-networking structure of EP also causes its high brittleness and poor wear resistance,restricting the EP products in many applications where high toughness or excellent antiwear property is required.The introduction of layered nanomaterials into EP to yield the nanocomposites has been proved to be one of the most effective ways to enhance the tribological properties.Nickel phyllosilicate（NiPS）is a new two-dimensional nanofiller,which has been widely applied in the fields of heavy metal ion adsorption and high-efficiency nickel-based catalyst.Moreover,due to the well-formed lamellar structure and adjustable morphological structures,NiPS is expected to be giant potential in improving the tribological properties of the polymer.In the present study,EP and NiPS were utilized as the matrix resin and the modifier,respectively,and EP nanocomposites were fabricated by the solution-mixing method.Then,under the condition of water lubrication,the influences of NiPS content and friction parameters on the tribological properties were investigated carefully,and finally,the mechanisms of antifriction and antiwear were explored and briefly discussed.Some useful conclusions are as follows:（1）NiPS nanoflowers（F-NiPS）were synthesized using a deposition-precipitation method and subsequently introduced into EP matrix to obtain the EP/F-NiPS nanocomposites.Then,the effects of F-NiPS content,applied load,friction rate,and lasting time on the friction and wear properties of EP/F-NiPS nanocomposites were investigated systematically.Results showed that F-NiPS could improve the tribological properties.With the increase of F-NiPS content,the average value of friction coefficient and wear rate were decreased first and then increased,and the lowest values of 0.1665and 0.816×10-6 mm3/N·m were obtained at the contents of F-NiPS was 5%and 3%,which were lower than 25.2%and 20.9%,respectively,when compared to that of pure EP(0.2225,1.031×10-6 mm3/N·m).Further studies have verified that the increased friction rate led to the decreased friction coefficient and wear rate,while the prolonged lasting time got the opposite results.By contrast,the friction coefficient increased continuously while wear rate increased first and decreased again along with the friction rate during the whole friction process.（2）ZnS nanoparticles were decorated on the surface of F-NiPS using hydrothermal treatment,forming the hybrid architecture of F-NiPS@ZnS.According to the tribological tests,F-NiPS@ZnS could enhance the antiwear property of EP nanocomposite effectively.By adding 5%of F-NiPS@ZnS,the minimum wear rate of0.405×10-6 mm3/N·m was obtained,showing a significant reduction by 60.7%than pure EP,which was also 50.4%lower than the case containing the same concentration of F-NiPS.However,it seemed that the added EP/F-NiPS@ZnS showed only a little positive influence on the antifriction property of EP.The lowest friction coefficient of 0.1940was exhibited as 3%filler was introduced,which was a bit higher than that of EP/F-NiPS（0.1833）but still lower than that of pure EP（0.2225）.Moreover,the friction coefficient and wear rate could be further restricted by elevating the friction rate,displaying better self-lubrication and wear resistance of EP nanocomposites,while the added load and time during the friction process deteriorated the tribological properties.（3）The carboxylated graphene oxide（GO-COOH）was co-blended with F-NiPS by vacuum filtration and then introduced into the EP matrix to get the EP/GO-COOH/F-NiPS nanocomposites.Results indicated that,during the range of study,the existence of GO-COOH improved the tribological properties of EP nanocomposites,making the friction coefficient and wear rate decline continuously.At the filler concentration of 7%,the minimum values of 0.1765 and 0.6265×10-6 mm3/N·m were obtained,which were respectively decreased by 20.7%and 39.2%in comparison with pure EP.Regarding the above two composites,the introduced GO-COOH could strengthen the self-lubrication and wear resistance simultaneously,making a balance between the antifriction and antiwear properties of EP nanocomposites.（4）He effects of F-NiPS@ZnS hybrids on the curing properties of EP nanocomposites solidification and thermal decomposition were investigated and quantitatively analyzed with a theoretical model.The activation energy and reaction order of EP curing and decomposition were obtained.The addition of F-NiPS@ZnS promoted the solidification of EP,with the filler content,the activation energy declined steadily and the lowest value of 44.6 k J/mol based on the Kissinger method was obtained with 5%F-NiPS@ZnS,which was 22.0%lower than that of pure EP（54.4k J/mol）.However,the presence of F-NiPS@ZnS did not change the reaction order of the curing process,still displaying the approximate first-order reaction.By fitting the autocatalytic kinetic model,the apparent dynamic equations for pure EP and the nanocomposites were determined,as fitted well to the experimental data,confirming the validity of the applied mathematical models.The thermal stability of EP was also improved by the addition of F-NiPS@ZnS.When the content of F-NiPS@ZnS reaches7%,the activation energy of thermal decomposition was 86.21 k J/mol（Carrasco method）,which is 27.9%lower than that of pure EP（119.60 k J/mol）.Figure 77 Table 9 Reference 114... |
