The Fabrication And Tribological Behaviors Of Polymer And Organics/inorganics Complex Nanoparticles

In this thesis, the polymer and organics/inorganics complex nanoparticles were prepared and their structures and properties were studied. The tribological properties of these nanoparticles as additives were investigated.The main research works are as follows:(1) Preparation, Structure Characterization and Tribological Behavior of Polymer Nanoparticles Polymer nanoparticles were synthesized using an solution polymeration method. The nanoparticles were characterized by Fourier transformation infrared ray (FTIR) spectroscopy and transmission electron microscope (TEM). Their thermal stability was investigated by means of differential thermal analysis (DTA),differential thermogravimetry (DTG) and thermogravimetry (TG). TEM micrograph shows that the samples are under 100 nm and dimensionaluniformity. After added polymer nanoparticles into water, its tribological properties were tested with four ball testing machine. The morphologies on the worn surfaces of the lubricated GCr15 steel were investigated by means of scanning electron microscopy (SEM). The results show that those polymer nanoparticles have good reduce-friction and anti-wear properties, compared to water. The proposed mechanism is as follows: under low load, deposition films consisted of these nanoparticles on the surface of steel sphere, which make those nanoparticles have good reduce-friction and anti-wear properties. Under high load, films of 'tribochemical reaction' of those nanoparticles, which make those nanoparticles have a good reduce-friction and anti-wear.(2) Preparation, Structure Characterization and Tribological Behavior of Tetrafluorobenzoic Acid-modified SiO2 NanoparticlesTetrafluorobenzoic acid-modified SiO2 nanoparticles were prepared using methodof surface-modified. The nanoparticles were characterized by means of electron diffraction (ED), TEM, FTIR, DTA and differential thermogravimetry (DTG). The surface modified sample disperses in organic solvents such as petroleum ether, liquid paraffin at room temperature. TEM micrograph shows that the mean graininess of the modified sample is about 30 nm, and the ED micrograph indicates that the structure of tetrafluorobenzoic acid-modified SiO2 nanoparticles is amorphous. After added nanometer SiO2 into liquid paraffin, its tribological properties were tested with four ball testing machine. The morphologies on the worn surfaces of the lubricated GCr15 steel were investigated by means of SEM. The results showed: the antiwear and load capability of liquid paraffin increased after adding nanometer SiO2. We inferred that is attributed to the generation of a surface film by way of tribochemical reaction.(3) Preparation, Structure Characterization and Tribological Behavior of Surface-modified TiO2 NanoparticlesSurface-modified TiO2 nanoparticles were synthesized in the ethanol with the surface modification agent of tetrafluorobenzoic acid and trifluoroacetic acid. Some analytical tools such as X-Ray Diffraction (XRD), TEM, TG and DTA were used to characterize the structure of surface modified nanoparticles. The nanoparticles exhibit good dispersity in the organic solvent and base oil. The results show that the mean sizes of the modified samples are about 40 nm and 100nm, and the XRD micrograph indicates that the structure of nanoparticles is amorphous. The tribological properties of nanoparticles as oil additive were investigated with a four-ball tribometer. The morphologies on the worn surfaces of the lubricated GCr15 steel were investigated by means of SEM. The result show that they are of good anti-wear and reduce-friction properties at mid-low applied load. We inferred that is was attributed to the generation of a surface protective film by way of tribochemical reaction.