摘要
在醇 -水体系中采用同阴离子共沉淀法合成了季铵盐修饰的 (NH4 ) 3 PMo12 O4 0 纳米微粒 ,以TEM、XRD、FTIR、TGA、DSC等多种分析手段表征了这种纳米微粒的形貌和结构 ,在四球试验机上考察了它们的摩擦学性能 .结果表明所合成的杂多化合物具有Keggin骨架结构 ,微粒粒径约 2 0nm ,在有机溶剂中可良好分散 ,作为一类新型润滑油添加剂 。
Surface modified (NE4)(3)PMo12O40 nanoparticles were synthesized in a mixture solution of water-ethanol with cetyl trimethyl ammonium bromide as a modification agent. The structure of nanoparticles was characterized by TEM, XRD, FTIR, DSC, TGA, etc., and their tribological properties as additives in liquid paraffin were investigated with a four-ball tribometer. In the preparation process, Na2HPMo12O40 (.) 14H(2)O was previously synthesized according to a literature. Firstly, ammonium chloride and cetyl trimethyl ammonium bromide were respectively put into the mixture solvent of distilled water and ethyl alcohol in a flask with stirring, then, the solution of Na2HPMo12O40 (.) 14H(2)O was dropped into the flask, immediately, a yellow precipitate was produced. After 1 h of continuous stirring and 12 h of standing, the yellow precipitate was collected by filtering and was rinsed with alcohol and water, individually, desiccated at room temperature. The yellow powder (marked as sample a) was the expect surface modified (NH4)(3)PMo12O40 nanoparticles. Non-modified (NH4)(3)PMo12O40 particle (sample b) was prepared with the same procedures as above, except that cetyl trimethyl ammonium bromide was not used. The dispersity of sample a and sample b were evaluated in solvents such as chloroform, benzene, liquid paraffin, and distilled water, at room temperature. The results show that sample a disperses in organic solvents, but it doesn't disperse in water, and sample b doesn't disperse in organic solvents or water. It indicates there are organic groups on the surface of sample a. TEM graphic shows that the mean graininess of sample a is about 20 nm, and the average grain-size of sample b is over 1 mum. This suggests that the modification agent can restrict the congregation of (NH4)(3)PMo12O40 nano-cores. The FTIR absorption spectra of sample a indicate that ( NH4)(3) PMo12O40 nanoparticles have a Keggin structure, and confirm the existence of organic groups. The XRD pattern confirms there are (NH4)(3)PMo12O40 nano-cores in sample a. The DSC and TGA curves of sample a show the decomposition temperature of (NH4)(3)PMo12O40 nano-core is about 300 degreesC. The tribological tests show that the synthetic nanoparticles as additive in liquid paraffin improve the antiwear and friction-reduction ability of the base oil, and the most appropriate additive concentration is 0.25%. According to our inference, this is attributed to the generation of a surface protective film, by way of tribochemical reaction.
基金
河南省自然科学基金资助项目 (0 0 40 30 40 0 )
河南省杰出青年基金资助项目~~
