Preparation And Application Of POSS-based Fluorescent Porous Polymers Containing D-A-D Structures

In recent years,scientific researchers have devoted themselves to developing various new materials to solve environmental problems such as water pollution,so as to reduce the threat of water pollutants to global biodiversity and human health.POSS-based porous polymers are composed of organic and inorganic units.Due to their large specific surface area,excellent thermal stability,functional diversity and chemical stability,they have been widely used in the fields of pollutant adsorption and detection.In this paper,two kinds of organic fluorescent molecules with different emission wavelengths and octavinyl sesimiloxane(OVS)were used as building units respectively to prepare silsesquioxane-based fluorescent hybrid porous polymers(PCSs)through Friedel-Crafts alkylation reaction,and to study the adsorption and detection performance of PCSs for pollutants in water.The details are as follows:Chapter 1.We synthesized an organic fluorescent molecule 4-[1-cyano-2-[4(diphenylamino)phenyI]ethenyl]-α-[[4-(diphenylamino)phenyI]methylene]benzeneacetonitrile(CN-DPB),its UV-vis absorption and fluorescence emission wavelengths are 438 nm and 585 nm,respectively,and the Stokes shift is 147 nm.Using CN-DPB and OVS as reaction monomers,we prepared POSS-based fluorescent porous polymer(PCS-DPB)containing D-AD structural units through a simple Friedel-Crafts reaction catalyzed by anhydrous aluminum chloride.The polymer was characterized by FT-IR,solid 29Si and solid 13C spectra,and the results confirmed that the hybrid porous polymer was successfully prepared.TGA data showed that the polymer had high thermal stability(Td5%=438℃).BET data show that the polymer has a high specific surface area(SBET=1292 m2 g-1)and a multi-pore structure.The results of PXRD and HR-TEM show that the polymer is amorphous material.Based on the porosity and fluorescence properties of PCS-DPB,we explored the adsorption of iodine vapor and dye and fluorescence detection of nitro compounds and metal ions by PCS-DPB.The maximum adsorption capacities of PCS-DPB for Congo red(CR),Rhodamine B(RhB),Methylene blue(MB),and Methyl orange(MO)were 594 mg g-1,836 mg g-1,and 202 mg g-1,107 mg g-1,respectively;the maximum adsorption capacity of iodine vapor is 1.82 g g-1;PCS-DPB showed high selectivity and sensitivity for 2,4-dinitrophenol and Ru3+with KSV of 729.1 M-1 and 2048 M-1,respectively.Chapter 2.Based on the above organic fluorescent molecule CN-DPB,we carried out structural design and introduced thiophene unit to broaden its conjugated system.Has a red light emission was synthesized via Knoevenagel organic fluorescent molecule 4-[(1Z)-1-cyano2-[5-[4-(diphenylamino)phenyl]-2-thienyl]ethenyl]-α-[[5-[4-(diphenylamino)phenyl]-2thienyl]methylene]-(αZ)-Benzeneacetonitrile(CN-DPBS).The stokes of the molecule are up to 180 nm.Using CN-DPBS and OVS as building units,POSS-based fluorescent porous polymers(PCS-DPBS)with near infrared emission were prepared by Friedel-Crafts alkylation reaction.The results of elemental analysis,BET and fluorescence detection showed that PCS-DPBS had high heteroatomic content,porosity and near-infrared emission characteristics.PXRD results show that the polymer has amorphous structure.Based on its porosity and fluorescence,we applied PCS-DPBS to the adsorption of heavy metal ions and iodine vapor and the detection of iodine elemental substances,and achieved good results.