聚酰亚胺/ZIF-8复合气凝胶的制备及二氧化碳吸附性能

Preparation of Polyimide/ZIF-8 Aerogels and Their Carbon Dioxide Adsorption Properties

开发兼具优异吸附性能及力学性能的CO2吸附材料,对于缓解温室效应具有重要意义。文中以聚酰胺酸盐(PAS)和聚酰亚胺纳米纤维为原料,采用双向冷冻干燥法制备了层状孔结构的聚酰亚胺气凝胶,通过原位生长,在气凝胶孔壁上负载二甲基咪唑盐(ZIF-8)得到了PI/ZIF-8复合气凝胶(PZA)。研究结果表明,所制备的复合气凝胶结合了ZIF-8和气凝胶的高孔隙率以及聚酰亚胺分子主链中酰亚胺环单元对于CO2良好的亲和作用,当负载量为44.3%时,CO2的吸附量为0.79 mmol/g,高于ZIF-8(0.69 mmol/g)和纯PI气凝胶(0.3 mmol/g)对CO2的吸附量。ZIF-8的引入提高了PZA-n复合气凝胶的力学强度,在40%应变时,PZA-30的压缩应力为19.8 kPa,与PI气凝胶相比提高了近2倍,同时该系列气凝胶仍保持良好的压缩回复性。

Developing novel materials with simultaneously good mechanical properties and excellent CO2 gas adsorption behavior plays an important role in mitigating the greenhouse effect caused by excessive CO2 emissions.In this paper,a polyimide(PAS)and polyimide nanofiber was used as raw material to prepare a polyimide(PI)aerogel with a layered pore structure.Subsequently,ZIF-8 was loaded on the pore walls of PI aerogel by in-situ growth to obtain a PI/ZIF-8 composite aerogel.These composite aerogels prepared in this paper combine the high porosity of ZIF-8 and the good affinity of imide units in the main chains of polyimide for CO2.When the ZIF-8 loading reaches 44.3%,the adsorption amount of CO2 is approximately 0.79 mmol/g,which is higher than that of ZIF-8(0.69 mmol/g)and pure PI(0.3 mmol/g)aerogel.Meanwhile,the mechanical strength of PZA-n composite aerogels increases with the increase of ZIF-8 loading.Under the 40%strain,the compressing stress of PZA-30 is 19.8 kPa,which is higher than that of pure PI aerogel,while it still maintains a good compression recovery.