Study On Ammoniated Modification Of Nano Diamond And Its Dispersion Behavior By Solid-pahse Grinding Technical

In recent decades,in addition to the traditional high-temperature and high-pressure and chemical vapor deposition method,the synthesis of nanodiamond by negative oxygen balance detonation is a widely applied method.Nanodiamond,which is synthesized by detonation,contains nanodiamond and some impurities,and it is necessary to remove nondiamond carbon and non-carbon impurities through chemical purification.The surface of nanodiamond contains different functionalized groups,including carbonyl,amino and hydrogen.The composition of these functionaized groups can be modified by chemical reaction,and makes the nanodiamond(DND)have a new performance,making it different from the raw diamond.Surface aminated modification is a chemical function method for nanodiamond when the surface of nanodiamond is terminated by an amine group.Earlier,researchers try to direct amination of nanodiamond based on the chemical treatment of a chlorinated surface by UV irradiation in ammonia gas,however,this will causing unnecessary pollution on the surface of nanodiamond,In order to aminated modification the surface of nanoscale diamond successfully without affecting the excellent properties and surface properties of nanodiamond,the new aminated modification method needs to be studied.In this paper,the aminated modification on the surface of nanodiamond was prepared by chemical-mechanical drinding.The surface structure of amination nanodiamond powder before and after were analyzed by FTIR spectrometer and the amino content was determinated by potentiometric titration.The aminated modification traetment is by ball milling technique,nanodiamond powder and amination reagent of ammonium chloride(NH4Cl)and grinding assistant of sodium chloride(NaCl)by ball milling.In the ball milling process,ammonium chloride was dissociated and amine functional groups immobilized on nanodiamond surface by covalently bond.The infrared spectra analysis of aminated modification of nanodiamond C-N stretching vibration peak at 1401cm-1,indicating that the attachments of amino groups on the suface of nanodiamond by ball milling process.Analyzing the influence factors of the chemical-mechanical grinding,the orthogonal experiment was carried out with the ratio of amination reagent,the ratio of grinding assistant,the ratio of grinding medium and the grinding time The optimal condition for aminated modification which was fond to be:the ration of amination reagent was 1:10,the ratio of grinding assistant is 1:5,the ratio of grinding medium is 1:5 and the grinding time is 2 h.Amine concentration is 173.7?mol/g was obtained.Based on the orthogonal experiment,the influence of each factors on the aminated modification of nanodimaond and its dispersion behavior was studied.It is found that it is well-dispersed in water by aminated modification on the surface of nanodiamond.The minimum particle size of 40.2nm can be detected by Malvin Zeta potentiometer,it appears to be very stable,showing no precipitation when stored for 2 years at ambient conditions.At the same time,the well-dispersed nanodiamond colloids solutions can be re-dispersed back to colloidal state after dried.It is found that the dry nandiamond powder can be re-dispersed back to colloidal solutions in DMSO,ethanol,DMF,water and other solvents,and its average particle size is less than 100nm,showing colloidal state,and it can also be stored for over 2 years at ambient conditions.