Hierarchical pore structure high polymer material and preparation method thereof

Abstract

The invention discloses a hierarchical pore structure high polymer material and a preparation method thereof, and belongs to the field of porous polymer materials. The preparation method comprises the following steps: (1) mixing hydrophobic silicon dioxide particles with an initiator, then adding a polymerizable monomer, a cross-linking agent, an assistant cross-linking agent and a pore-foaming agent, and uniformly stirring to obtain a reaction mixed solution; (2) adding water into the reaction mixed solution, and stirring until a gel emulsion is formed; and (3) performing staged thermal polymerization on the gel emulsion to obtain the hierarchical pore structure high polymer material. According to the invention, the content and size of pores and pore throats in the material can be effectively regulated and controlled, and the high polymer material with the multistage micron pore structure is obtained. The material is good in heat transfer in the polymerization process, free of implosion phenomenon and high in product percent of pass; a wet material obtained by polymerization is rich in pores, small in resistance in a mass transfer process and relatively high in drying rate; meanwhile, the hierarchical pore structure high polymer material disclosed by the invention has excellent machining performance and static load resistance.

Description

technical field [0001] The invention belongs to the field of porous polymer materials, in particular to a polymer material with a hierarchical porous structure and a preparation method thereof. Background technique [0002] Porous materials have the advantages of low relative density, high specific strength, large specific surface area, sound insulation, and heat insulation. The preparation of porous materials has always been a hot spot of concern. [0003] At present, the commonly used preparation methods of porous materials mainly include gas foaming method, solvent porogenic method and template method, etc. Compared with foaming method and solvent porogenation method, template method is favored because of its advantages of easy and precise control of pore size and distribution. Gel emulsions are a common template for preparing low-density porous materials. Gel-emulsions are also called highly concentrated emulsions and high internal-phase ratio emulsions. It has been r...

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Problems solved by technology

It has been reported in the literature that the volume fraction of the dispersed phase of the traditional gel emulsion method must be greater than 74% (the critical value for the dispersed phase droplets to be tightly packed into interconnected spheres), so the density of the porous material prepared by this method is lower than 0.30g / cm3

When the volume fraction of the dispersed phase is greater than 90% or more, pore throats will be formed on the pore wall of the porous material (the material density is lower than 0.10g / cm3), and the internal system of the material has partially interpenetrating Open-pore structure, but at this time the mechanical properties of porous materials will be greatly affected, showing low mechanical strength and machining performance, and the application fields and occasions are greatly limited; for density greater than 0.10g / cm3, if one wants to form pore throats and partially interpenetrating open-pore structures inside the material, it is usually achieved by introducing surfactants into the gel emulsion system to reduce the interfacial tension of the gel emulsion system, but this The method has defects such as instability and easy demulsification of the prepared gel emulsion, and problems such as surfactant leakage and secondary pollution are also prone to occur in the later use of porous materials.

[0004] For applications with high mechanical properties and machining requirements, porous materials with relatively high density (0.20~0.60g / cm3), but there are many continuous phases (oil phase) in the preparation process of this type of material, and a large amount of polymerization heat will be generated during the oil phase polymerization process. In addition, the content of the continuous phase (oil phase) is relatively large, and the oil film in the prepared W / O type (water-in-oil) gel emulsion is relatively thick and has a continuous structure, and the porous material obtained by polymerization is closed. Porous materials make the drying of wet materials to dry materials consume a lot of energy, the mass transfer process is extremely difficult, and the drying cost is high. The large-scale production and wide application of materials are greatly restricted.

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