Preparation And Related Properties Of Polyimide / Reduced Graphene Oxide Composite Sponge

In recent years,the occurrence of oil spills on the sea surface and oily wastewater and organic solvents produced by humans have caused serious harm to water resources.Physisorption has become the most commonly used method to deal with water pollution due to its low cost and environmental friendliness.However,the adsorption capacity of traditional oil-adsorbing materials needs to be improved,so it is urgent to develop high-performance adsorption materials.Graphene sponge is a three-dimensional mesh-like porous material which has a high adsorption capacity for oil pollution.However,current graphene sponges are difficult to have strong mechanical properties and thermal stability,which is not conducive to the reuse of materials.Therefore,in recent years,researchers have developed graphene composite sponge materials modified with polymers.Polyimide is a polymer material with a five-membered imide ring structure in the main chain of the molecule and has excellent mechanical and high temperature resistance properties.In this paper,the combination of polyimide and graphene was selected to make the graphene composite sponge have good heat resistance and mechanical properties,and easy to reuse.Moreover,the preparation method of the composite sponge has the advantages of low cost and easy mass production.The specific research content includes the following three aspects:（1）The experimental conditions were determined by studying the effect on the molecular weight of poly（amic acid）by changing the molar ratio of reaction monomer,reaction temperature,reaction time,and solid content.The storage stability of the polyamide acid solution was also studied.（2）The polyimide/reduced graphene oxide composite sponge was prepared by introducing water-soluble poly（amic acid）on the graphene sheet,and its morphology,composition,thermal stability were characterized,and its adsorption and other properties were also studied.Studies showed that the adsorption capacity of composite sponge for motor oil,silicone oil,kerosene,pump oil,toluene and DMF were 27.3,28.7,30.9,36.6,33,and 52.5 g?g^-1,indicating that the composite sponge has functional adsorption capacity;after ten repeated adsorptions,the adsorption capacity of composite sponge for the pump oil decreased by 20.8%of the initial value,indicating that the composite sponge has some cycle stability.（3）The polyimide/reduced graphene oxide composite sponge was prepared by the foaming method,and its morphology,composition,thermal stability were characterized,and its adsorption and other properties were also studied.Studies showed that the adsorption capacity of composite sponge for motor oil,silicone oil,kerosene,pump oil,toluene and DMF were 29.5,29.9,31.6,37.9,34.3,56.8 g?g^-1,indicating that the composite sponge has better adsorption capacity;after ten times of repeated adsorption,the absorption capacity of composite sponge for the pump oil only decreased by 6.3%of the initial value,indicating that the composite sponge has excellent cycle stability.