【作者】 易彩虹；

【导师】 李晓杰；

【作者基本信息】 大连理工大学 ， 材料加工， 2011， 硕士

【摘要】 爆轰纳米金刚石具有超硬特性和良好的化学稳定性、生物兼容性,具有很广阔的应用前景,但是由于团聚问题没有得到解决,始终制约其应用进展。因此,推动爆轰纳米金刚石应用研究和产业发展必须对爆轰纳米金刚石进行解团聚处理。本文选用爆轰纳米金刚石黑粉(DND-B);高纯度爆轰纳米金刚石灰粉(UFDND-A);爆轰纳米金刚灰粉(DND-A)。采用酸处理氧化、气相热处理氧化对DND-B进行表面改性,机械化学改性对DND-A和UFDND-A进行表面改性调节其表面官能团构成来实现在不同溶剂中稳定分散。采用红外光谱、激光粒度仪、透射电镜对改性后的纳米金刚石(MDND-A、MUFDND-A)的官能团、粒度分布和形貌进行评估。对MDND-A和一定比例的表面活性剂、助表面活性剂、油相、蒸馏水制成的微乳液的形成机理、机械改性加入的表面活性剂的表面吸附机理进行研究和归纳。氧化性酸氧化处理DND-B,实验表明：颗粒表面的烃类等基团被氧化成羧酸官能团,离解使得颗粒负电性最强。红外光谱表明：高温热处理可以氧化DND-B和UFDND-A表面的含碳官能团变成羧酸官能团,具有明显的解团聚作用,使颗粒减小,再加上表面含氧官能团羧基的增多,有利于DND-B和UFDND-A在水中实现较好的分散。X射线衍射分析表明空气中热处理对DND-B和UFDND-A表面的非金刚石相具有氧化作用,同时还可以对金刚石晶形貌有所改善。对UFDND-A进行机械化学改性,激光粒度仪表明：所得到的MUFDND-A粒度分布为评判标准,得到最佳的研磨改性工艺条件为：研磨介质氧化锆为250g,分散介质水为100g,吐温为分散剂,UFDND-A与吐温质量比q为1左右,研磨转速为2000n/min,研磨时间为1.5h。DND-A经过油相机械化学改性后的,油相非极性官能团C-H在DND-A表面发生了很好的吸附,油相的基团和DND-A表面的亲水基团-OH、-COOH发生了键合,使得MDND-A表面羟基-OH,羧基-COOH较DND-A有所减少。机械化学改性后的(MDND-A),形成的MDND-A O/W微乳液体系稳定,微乳液静置期间,DND-A纳米粒子存在逐渐长大的现象,但是粒子长大的速度很慢,七周后粒子平均粒径由原来的13.04nm增大到26.14nm,仅仅长大13.1nm。在静置过程期间,未发生沉淀和分层现象。MDND-A表面的非极性官能团C-H增加,极性官能团-OH、-COOH的减少对MDND-A形成稳定的MDND-A O/W微乳液有很重要的意义。DND-A经过吐温机械化学改性后,DND-A表面吸附了大量亲油性官能团烃基。tween-80在DND-A表面吸附,形成了很好的覆盖层,DND-A表面官能团几乎为tween-80的官能团。通过本文研究,可以工程化的解决纳米金刚石硬团聚问题,实现纳米金刚石在水中的稳定分散,有利于推动这种优良性能的纳米材料的应用。更多还原

【Abstract】 Because of possessing the characteristics of superhardness, excellent chemical stability and biocompatibility, detonation nano-diamond is a proming and valuable powder material and has broad application prospects. The problem of deagglomeration which has not been resovled restrict its application.therefore, the deagglomeration processing of nano-diamond have impromtant significance for the promotion of applied research and industrial development.The paper choose detonation nano-diamond black power (DND-B), ultra-fine detonation nano-diamond ash power (UFDND-A), and detonation nano-diamond ash power (DND-A) as samples. Measures such as tacid oxidation,gas heat oxidation are used to modify DND-B, Mechanical and Chemical Modification(MCM) is used to modify the surface functional groups of DND-A and UFDND-A which make MDND-A and MUFDND-A disperse stably in diffrenet solvents.Fourier Transform Infrared Spectroscopy(FTIR), laser particle size analyzer,Ttransmission Eelectron Mmicroscope(TEM) are used to assess the functional groups,particle size distribution and morphology of modified nano-diamond.the paper study and summary the formation mechanism of micro-emulsion which made by a certain proportion of modified nano-diamond, surfactant, cosurfactant, oil, distilled water and surfactant surface adsorption of MCM.Oxidizing acid oxidate DND-B, experiments show that:hydrocarbon groups of particles surface are oxidized to carboxylic acid functional groups, dissociation make negatively charged particles become stronger. FTIR indicates that:high-temperature heat treatment can oxidize the carbon functional groups of DND-A and UFDND-A surface into carboxylic acid functional groups and have deagglomeration, the increase of oxygen-containing carboxyl functional groups is conducive to achieve nano-diamond disperse stably in water. X-ray diffraction analysis show that the air heat treatment can oxidate non-diamond phase of detonation nano-diamond surface, at the same time, can improve the diamond crystal.UFDND-A are modified by MCM, laser particle size analyzer show that:making the particle size distribution of MUFDND-A as evaluation criteria, the best grinding conditions are determined:the weight of grinding media zirconia is 250g, dispersion medium water is 100g, mass ratio q of UFDND-A and dispersant Tween-80 is about 1, grinding speed is 2000n/min, grinding time is 1.5h.DND-A are modified by the oil phase MCM, the non-polar functional groups C-H of oil phase have good adsorption on the surface of DND-A, the functional groups of oil phase and surface ydrophilic groups-OH,-COOH of the DND-A bond together, which make surface hydroxyl groups -OH, carboxyl group -COOH of MDND-A decrease compared with DND-A. MDND-AO/W micro-emulsion system is stable, MDND-A grow up during standing, but the particles grow slowly, seven weeks later, the average particle size increase from the original 13.04nm to 26.14nm, just grow up 13.1nm. Sedimentation and stratification did not occur.The increase of non-polar functional groups C-H and the reduction of polar functional groups-OH,-COOH of MDND-A have important significance to form stable MDND-A O/W micro-emulsionDND-A are modified by tween MCM, the surface of DND-A adsorb a large number of hydrophobic alkyl functional groups. tween-80 have good adsorption on the DND-A surface and form a good cover, the surface of DND-A are almost the functional groups of tween-80.The study can solve the hard agglomeration of nano diamond to achieve nano-diamond disperse stably in water, which help promote the application properties of excellent nanomaterials.更多还原