Synthesis And Properties Of Conjugated Microporous Polymers Based On Spirobifluorene And Triphenylamine

Organic microporous polymers(MOPs)are porous materials with a high specific surface area and abundant microporous structure.Compared with inorganic porous materials and metal-organic framework compounds,the organic microporous polymers have lower skeletal density,more excellent pore properties,synthesis methods are diverse,modifiable properties.From the view of molecular,organic microporous polymer is entirely formed through the covalent bond,resulting in excellent properties like thermal stability,physical and chemical stability,acid and alkali resistance and moisture resistance.Therefore,in recent years,due to its excellent properties,organic porous materials have become hot topics in the field of porous material development and the most advanced frontier issues.In my thesis,organic conjugated microporous polymers based on spirobifluorene and triphenylamine were designed and synthesized.Their thermodynamic,optical and electrochemical properties and photocatalytic properties of hydrogen production from water were tested.In Chapter 2 and Chapter 3,we design and synthesize porous polymers of spirobifluorene and triphenylamine with benzothiadiazole,quinoxaline and tetrastyrene,respectively.tested by TGA,XRD,FT-IR,SEM,and Chemical tests to explore the effect of the selection of different electron acceptor units on the photocatalytic performance of hydrogen production.In the Chapter 4,based on the research of the first two chapters,two polymers were choose,with adjusting the polymerization these polymers have the best photocatalytic properties for hydrogen production in the two groups.The random Ternary copolymerization based on spirobifluorene and benzothiadiazole,triphenylamine and benzothiadiazole were designed and synthesized,and their properties were further studied and analyzed.The main work of this paper is as follows:(1)In the second chapter of this paper,the UV absorption spectra of the polymer PSBF-BT are red-shift,the bandgap is narrower,and the LUMO level is lower.From the analysis of hydrogen performance structure of photocatalytic hydrogen evolution,the polymer PSBF-BT has the better photocatalytic activity,and the catalytic hydrogen evolution rate is 1.44μmol/h.So,a preliminary conclusion of this chapter,through the design choice of different electron acceptor unit decrease polymer band gap,lower LUMO energy levels,we can get a greater scale of light absorption,photocatalytic hydrogen production from water performance more excellent conjugate porous materials.In order to further verify this conclusion,we carried out the third chapter.(2)In the third chapter,the band gap of the polymer PTPA-BT is narrower,and the LUMO level is lower,with better photocatalytic activity,and the photocatalytic hydrogen evolution rate is 1.13μmol/h.The results with the first chapter agree with that the photocatalytic performance of the polymer PSBF-BT is better than PSBF-QX and PSBF-TPE,also shows that the electron acceptor unit with narrow band gap of benzene and thiamethoxam 1,the introduction of more than sinensis moiety and four styrene unit could improve the performance of the polymer photocatalytic hydrogen production from water.However,compared with PSBF-BT,which was prepared by the polymer PTPA-BT and the second chapter,the band gap of PTPA-BT was less than PSBF-BT,but the polymer PSBF-BT was better in photocatalytic performance.In analysis,by introducing different monomer adjust the LUMO energy levels and the band gap of polymer,the lower LUMO energy level,the better the performance of photocatalytic hydrogen production from water decreases in a certain range polymer band gap is conducive to improve the photocatalytic performance,but not a polymer band gap is narrow photocatalytic performance will be better.(3)In the fourth chapter,in order to further explore the band gap of polymer and LUMO energy levels and the performance of the photocatalytic hydrogen production from water relations,we synthesized two series of six kinds of polymer and show good physical and chemical and thermal stability and porous structure.Among them,the LUMO energy levels of the polymer PSBF-BT-2 and PTPA-BT-2 were the lowest in the same group,with the band gap all in the middle value,and the photocatalytic performance was the best,and the catalytic hydrogenation rate was 3.12μmol/h and 3.81μmol/h.It can be known that the lower photocatalytic performance of the polymer LUMO level is better,and the gap is not the narrower the photocatalytic performance is better.Therefore,the optimal photocatalytic performance can be obtained by introducing different proportional to the receptor units to regulate the polymer band gap and LUMO level.It is analyzed that reducing the LUMO energy level can effectively improve the hydrogen performance of photocatalytic water.In the study of photocatalytic hydrogenation,there is an optimal value in the polymer band gap,and the better it is when the band gap is closer to the optimal value.