Preparation And Application Of Hierarchical Porous Polystyrene Foam

Many oil spill accidents polluting ocean often happen.The dangers of the oil spill at the sea are not only harmful to water quality and the ecological environment,but also to the health of aquatic organisms and human beings.People pay more and more attention to the study of oil sorbent materials.The oil absorbing resin is a functional polymer material capable of adsorbing petroleum.It has the characteristics of a three-dimensional reticulation or porous structure,self-swelling and low density.It also has the advantages of economic,high efficiency and easy recovery in the treatment of oil spill at the sea.Polymerized concentrated emulsion is one of the methods of synthesizing oil absorbing resin.It has the advantages of fast polymerization speed,adjustable pore size,uniform pore diameter and high specific surface area.The oil absorption property of oil absorption resin is related to the oil affinity group and pore structure.In this paper,from the microstructure,the oil absorption performance of polystyrene foam can be improved by forming a regenerated hole on the pore wall.By the incorporation of chemical foaming into polymerized concentrated emulsion,we finally get a hierarchical porous polymer with hierarchical structure with higher oil absorption performance.Firstly,polystyrene foam with different dispersed phase volume and different crosslinking agent consumption was prepared by polymerized concentrated emulsion.The best concentrated emulsion formulation was determined by comparing the samples:the volume fraction of dispersed phase was 75%,and the cross-linking agent amount was 15%.The sample obtained by this formula has complete pore morphology,uniform pore diameter,the hole wall thickness and the material strength are suitable for later foaming treatment.Secondly,on the basis of the best concentrated emulsion formulation,the effects of three different foaming agents(NaHCO3,azodicarbonamide,diisopropyl azodiformate)on the hierarchical porous polystyrene foam were studied.As a result,we chose diisopropyl azodiformate as the best foaming agent which had no effect on the original pore structure.The effects of diisopropyl azodiformate consumption on the hierarchical porous polystyrene foam were studied through multiple comparison test.The results show that when the consumption of diisopropyl azodiformate is 3%,the number of regenerated pores is the most.And it has the maximum porosity and the lowest density.In order to improve the dispersivity of diisopropyl azodiformate,we determined to add toluene,and studied the effect of different toluene consumption on the hierarchical porous polystyrene foam.The results showed that when the consumption of toluene was 3%,the number of regenerated pores was the largest.Finally,we tested the oil absorption properties of the original polystyrene foam,the hierarchical porous polystyrene foam prepared by adding 3%diisopropyl azodiformate and the hierarchical porous polystyrene foam prepared by adding 3%diisopropyl azodiformate and 3%toluene.The results showed that the oil absorption rate of hierarchical porous polystyrene foam prepared by adding 3%diisopropyl azodiformate and 3%toluene increased.The oil absorption rate is 1900%.Moreover,the oil holding rate of the foam increase greatly,the water absorption rate and the oil-water displacement rate decreases correspondingly.Hierarchical pore structure can effectively improve the absorption properties of polystyrene foam material.