三嗪超交联聚苯乙烯基多孔聚合物的设计与制备

Hypercrosslinked porous polymers (HCPs) possess advantages of high specific surface areas, adjustable functionalities, controllable pore structures and low cost. Therefore, they have widespread application prospect in many fields such as gas storage, adsorption/separation, drug release and catalysis. Development of crosslinked structure is of importance to construct novel HCPs with optimized porous structures and new properties in emerging fields. Herein, a series of triazine-crosslinked HCPs from polystyrene were fabricated through Friedel-Crafts hypercrosslinking reaction, in which cyanuric chloride was introduced as the crosslinking agent. Using linear polystyrene and polystyrene spheres as raw materials, HCPs with three-dimensional network nanostructure and spherical morphology were obtained, respectively. Field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, N₂ adsorption-desorption tests were performed to investigate the microstructure, chemical structure, and pore structure. The results show that the triazine crosslinking structure provides much higher surface area and richer mesopores below 10 nm in the asobtained HCPs, compared with previously reported carbonyl crosslinking structures. The hypercrosslinking conditions of raw material concentration and crosslinking time were further investigated. The results show that lower polystyrene concentration gives rise to higher surface area in the resulting three-dimensional network HCPs because of developed mesopores; while an increase of hypercrosslinking time results in enhanced microporous surface area and the rising tendency levels off after 2 h. Furthermore, the proposed triazine crosslinking strategy can be implemented using commercial polystyrene, leading to similar triazine-crosslinked HCPs with three-dimensional network structure. Therefore, our finding opens up a new avenue for waste-to-wealth recycle of polystyrene, which is one source for causing so-called “white pollution”.