Preparation And Properties Of MOF-Ti Based Nanocomposites

Electrorheological?ER?fluid is mainly composed of polarizable particles evenly dispersed into the insulating oil to form a type of two-phase fluid.The rheological properties of this type of fluid can be instantaneously reversible under the action of an electric field.This is explained by the fact that,under the action of the electric field,polarizable particles inside the electrorheological fluid attract each other,thereby forming a chain structure arranged along the direction of the electric field.Because the electrorheological fluid with good performance can respond quickly and reversibly under the action of the electric field,it is all a matter of wide range of applications in mechanical engineering,automotive engineering and other fields.So far,there are numerous materials used in the field of ER fluid,including conductive polymers and inorganic semiconductors.Among these materials,TiO₂ is a part of the most studied.The advantages of TiO₂ include high dielectric constant,superior thermal stability,non-toxic products,and various preparation methods.However,TiO₂ has insufficient yield stress and poor anti-settling properties,which limit its electrorheological effect.Metal-organic framework materials?MOFs?are a fast-growing coordination polymer,which has a three-dimensional pore structure,with metal ions as connection points,and organic ligand support to form a 3D spatial extension.In addition to zeolite and carbon nanotube.Another type of new porous materials,MOFs,is widely used in catalysis and energy storage.Due to the unique pore characteristics and large specific surface area of malodorous materials,they can play a certain role in improving the polarization effect of the particle.Therefore,MOFs are also currently used in the field of electronically and as a solid dispersed phase material for electrorheological fluids.The following are the main research contents:?1?We use TiO₂ to reduce the conductivity of MOF,so that its electrorheological fluid can work under high voltage.First,the solicitation method was used to prepare MOF?MIL-125?nanoparticles,and then MOF was used as a precursor to coat TiO₂on the surface with a controlled hydrolysis method,and then the core-shell structure particles were dispersed in silicone oil to make an electrorheological fluid.Test its electrorheological properties.Compared with electrorheological fluid with MOF as the dispersed phase,electrorheological fluid of the core-shell structure particles has a higher electrorheological efficiency.?2?A series of doped MOF particles were prepared by chromium ion doping.Compared with pure MOF,the effects of chromium ion doping on particle morphology,structure and electrorheological properties were studied.It is important to note that a suitable doping ratio is beneficial to improve the electrorheological properties.After that,prepared doped MOF particles are enclosed in a tube furnace and heated and calcined to remove the organic matter in the MOF.Calcined and unconfined samples are characterised by SEM,TEM,XRD and other methods.Finally,an electrorheological fluid was prepared and its electrorheological properties were verified to study the effect of chromium doping on its electrorheological properties.?3?In this experiment,MOF titanium was prepared by solvothermal method,and the obtained MOF titanium was calcined to obtain mecopterous titanium oxide.Through oxidation and compounding with titanium oxide/polyaniline nanocomposite particles were finally obtained.During the experiment,XRD,SEM and electro-rheological properties were analyzed on all the prepared samples,and finally the experimental conclusion was drawn:the performance of pure MOF titanium is not good,the strength is not high,and the electro-rheological properties are not ideal;After calcination of MOF titanium,titanium oxide is obtained,and the rheological properties have been greatly improved,but the strength is still not high.Finally,after the titanium oxide and polyaniline are combined to prepare their nanocomposites,the rheological properties and strength of the samples are both It has been greatly improved.