Preparation And Application Of Hyper-cross-linked Microporous Polymers

Hyper-cross-linked microporous polymers(HCPs)with high specific surface areas,low skeleton density,large pore volume,excellent chemical and environmental stability and flexibility of design and functional,have potential application in the areas of gas storage and separation,catalysis and sensor.The past decades witnessed the rapid development of HCPs,its massive preparation and the control of the structure of the HCPs,however,are still big challenges.In this thesis,two kinds of hyper-cross-linked polymers,including pitch-based HCPs and bismaleimide-based HCPs,were prepared via facile and effective approaches.Furthermore,the gas adsorption and separation ability were studied.The main contents are as follows:(1)We employed the previously ignored building blocks and prepared hyper-cross-linked polymers(HCPs)with high surface area via one-step Friedel-Crafts reaction.Every year petro-and coal-chemical industry produces massive pitch,mainly composing of phenols,polycyclic aromatic hydrocarbons and heterocyclic compounds.And CHCI3 was used as not only the solvent but also the crosslinker,which simplify the operation of the experiment.The as-prepared polymers were characterized by FT-IR,13C NMR,PXRD,SEM,TEM and N2 adsorption/desorption measurement.Depending on the place of origin,petroleum-pitch-based HCPs have a maximum BET surface area of 1337 m2 g-1 with good chemical and environmental stability.The inherent heteroatoms in the pitch(sulfur)and the introduced heteroatom(chlorine)endow the obtained HCPs excellent gas adsorption capability.The uptake capacity for CO2 reaches up to 17.74 wt%(1.0 bar,273 K)and the hydrogen storage is up to 1.83 wt%(1.13 bar,77 K).In addition,the pitch-based HCPs also show high organic vapors capture capacity at room temperature(cyclohexane:1115 mg g-1;ethyl acetate:685 mg g-1;methanol:1198 mg g-1 and benzene:890 mg g-1).(2)A new kind of hyper-cross-linked microporous polymer were prepared via Friedel-Crafts acylation,which was not been adopted to synthesis polymers because carbonyl group would reduce the activity of the aromatic ring.In this thesis methylbenzene,naphthalene,coal tar,coal tar pitch and 1,3,5-triphenylbenzene were employed to react with triphosgene,and it was found that the carbonyl group has little influence on the activity of the large aromatic ring,such as coal tar,coal tar pitch and 1,3,5-triphenylbenzene.The prepared HCPs were characterized by FT-IR,N2 adsorption/desorption measurement,and the electrochemical performance of carbonized HCPs was measured by electrochemical workstation.The BET surface areas of the prepared HCPs is 1357 m2 g-1,and they possess good gas adsorption ability(CO2:15.86 wt%,273 K/1.0bar;H2:1.57 wt%,77 K/1.13 bar).Besides,the oxgyen-doped carbon materials prepared by pyrolyzing the HCPs show a high specific capacitance(409 F/g at 1.0 A/g)and good cycling stability(99.3%capacitance retention after 10000 cycles),demonstrating the advantages of the porous structure and oxgyen-rich chemical composition of HCPs.(3)A novel type of hypercrosslinked organic microporous polymer(HOMP)has been successfully prepared based on the radical copolymerization of bismaleimides and divinyl benzene.In comparison with the HOMPs prepared with crosslinking techniques,the new radical strategy circumvents some intractable problems,such as low atom economy,structure irregularity and corrosive by-products.The obtained HOMPs have defined molecular structures due to the intrinsic alternating copolymerization properties of the two monomers.The HOMPs were characterized by FT-IR,13C NMR,TGA,EA,SEM,TEM and N2 adsorption/desorption measurement A maximum BET surface area of 841 m2 g-1 and high gas capture capacity(CO2:11.22 wt%,273 K/1.0 bar;H2:0.82 wt%,77 K/1.13 bar)were achieved.The CO2/N2 selectivity of HOMPs is 51.02/1,surpassing the selectivity for many other porous polymers.In addition,the polymers also displayed good chemical and thermal stability,which is critical for the practical application.