Oxazoline Functionalized Hypercrosslinked Polymers And Their Post-Modifications

Hypercrosslinked microporous polymers(HCPs)own high specific surface area,abundant microporous and ultra-microporous pores,stable physical and chemical and thermodynamic properties,have been researched and applied in many fields like,gas adsorption and separation,heterogeneous catalysis,water treatment,and drugs delivery etc.It can be prepared under mild condition and synthesized by extensive low cost monomers which are benefit to industrial produce.In order to achieve better application efficiency,functional groups are incorporated into the hypercrosslinked polymers,and it has been proved to be an effective method to combine the intrinsic advantages of HCPs with innovative properties of function groups for diverse applications.For preparation of functionalized HCPs,some functional monomers are difficult to synthesize or only can obtain HCPs with low specific surface area.However,post-modification of HCPs is often conducted under harsh experimental conditions,or merely few types of functional groups can be introduced through this way.Given that,if a flexible and effective modification method can be discovered,functionalization of HCPs and their applications will be much easier and more applicable.In this work,nitrile-functionalized hypercrosslinked polymer HCP-TPB-CN was fabricated by copolymerizing 1,3,5-trinaphthylbenzene with 2-naphthalenenitrile through the solvent kitting strategy.The chemical structure,textual properties and gas uptake capacity of the resultant materials were analyzed by Fourier transform infrared(FT-IR)spectrometer,thermogravimetric analyze(TGA),micromeritics ASAP physisorption analyzer,high pressure gas adsorption instrument etc.The experimental results showed that copolymer HCP-TPB-CN has a BET surface area of up to 2017 m²g^-1 and extensive micropores.Moreover,introducing nitrile functional groups apparently promoted the affinity between CO₂ and porous networks,thus the material exhibited high CO₂ adsorption capacity of 21.3 wt%(273 K,1 bar)and 11.9 wt%(298 K,1 bar).In addition,the HCP-TPB-CN possess abundant ultra-micropores whose pore diameter around 0.6 nm,that made it displayed good performance for methane adsorption under high pressure,and its excess gravimetric adsorption capacity reached 0.21 g/g.And this work further designed HCPs functionalized with active oxazoline groups as versatile reactive sites for post multiple modification reactions.The experiment based on the nitrile-functionalized HCP-CN,then the CN groups were converted into oxazoline rings to gain the oxazoline-functionalized HCP-Oxa.The highly reactive oxazoline groups enable to react with diverse functional groups that endow the HCP-Oxa accomplished by post-modified with target properties according to specific application requirements.After post-functionalizing the HCPs-Oxa with sulfonic acid,amino,and carboxyl groups,the hydrophobic HCPs transferred to hydrophilic and they could be applied to remove metal ion in water treatment.This strategy break the limitations of traditional functionalization methods that require to redesign or prepare new functional precursors or synthesize new functional monomers for different application targets,providing new ideas for the design and preparation of functional HCPs.