Study On The Synthesis And Mechanism Of Polymer And MOFs Through Supersonic Air-flow Method

Solid phase reaction has advantages such as high selectivity,high yield and simple process.It has become an important method to prepare new solid materials.As an important branch of solid phase synthesis,mechanochemical methods have attracted more and more attentions.Traditional mechanochemical methods include ball milling,grind,screw extrusion,high pressure and other methods.These methods have many disadvantages,such as high production cost,low energy feed,long reaction time and difficult industrialization.In recent years,our research group has used a new mechanochemical method,supersonic airflow method,to inaugurate a new path for solid phase reaction.This method has the advantages of simple operation,low energy consumption,high efficiency,green environmental protection and easy industrialization.In this paper,different types of porous organic frameworks were synthesized by supersonic airflow method.The influences of experimental conditions on the experimental results were explored.The reaction mechanism was explored and the related dynamic models were also established.At the same time,a microwave heater was designed to verify the assistant effects of microwave to the supersonic airflow solid state reaction.(1)Three kinds of metal organic frameworks,Cu,Zn and Cd,were synthesized by the supersonic airflow solid state reaction.Their structures were characterized by fourier transform infrared spectroscopy(FT-IR),powder X-ray diffraction(XRD),field emission scanning electron microscopy(SEM)and thermal analysis(TG-DSC).Two of the organometallic frames were calcined to prepared the CuO and ZnO.The cyclic voltammetry and charge discharge curves of CuO is carried out and the results proved the good electrochemical reversible performance of the product.The photocatalytic degradation of ZnO with chlorophenol was also carried out.The results showed that97.8 % of the chlorophenol could be degraded with 20 min irradiation upon visible light,which proved the ZnO has a good photocatalytic effect.(2)Two kinds of polyimide and one kind of poly(p-phenylenediamine)were synthesized by supersonic airflow method.The structure was characterized by FT-IR,P-XRD,SEM and TG.The results showed that the above materials were successfully synthesized.Based on the second generation of the supersonic flow reactor,which focalize the raw materials to the one-way target,microwave heater was designed and added to the device to promote the synthesis of the polyimide system.And the results showed that the generating rate of polyamic acid was significantly faster with microwave heater,from 20 min to 5 min.The yield was also raised from 93.8 % to94.2 % which proved microwave heater has a positive effect on the synthesis of polyimide.(3)The reactions were monitored with non-situ powder X ray diffraction.The results were converted into conversion rate(alpha)and further fitted.Taking the metal organic framework of Cadmium as the research object,the influence of reaction time on the experimental result was obtained.The best kinetic model is two-dimensional diffusion(D2)model.Taking the synthesis of barium carbonate as the research object,three different experimental conditions,such as the particle size of the raw materials,the reaction time and the reaction pressure,were practiced to determine the influences of the reaction conditions to the experimental results.And the mathematical model of the conversion rate with these three factors was also established by genetic function approximation.