Preparation And Application Of Room Temperature Cross-Linked Polymeric Porous Materials By High Internal Phase Emulsion Template Method

Polymeric porous material(poly HIPE)prepared by the high internal phase emulsion(HIPE)templating method has promising applications in the fields of adsorption,catalysis,and tissue engineering due to its easily tunable pore size,high porosity,and large specific surface area.However,the current method of curing the continuous phase of HIPE to form a solid porous material skeleton frequently entails polymerization and crosslinking of monomers,necessitating reaction conditions such as high temperature or radiation,which are not only energy-consuming,but also have an impact on the material’s re-formation in various application scenarios due to its three-dimensional network structure formed during the polymerization.Although linear polymer solution can use directly as continuous phases to prepare HIPE,their applications are restricted due to poor properties.In this study,a linear copolymer with room temperature cross-linked groups(ketone carbonyl group),hydrophobic component,and hydrophilic component was synthesized by emulsion polymerization,which could be applied to prepare a water-in-oil(W/O)HIPE stabilized by inorganic nanoparticles.The obtained HIPE can be shaped arbitrarily and crosslinked at room temperature through ketone-hydrazine crosslinking.The procedure is low-energy,convenient,and ecologically friendly,and easy to manufacture and apply on a large scale.The main work of this study is as follows:(1)Linear copolymers with ketone carbonyl groups were synthesized by emulsion polymerization with diacetone acrylamide as the functional monomer,styrene as the main monomer,butyl acrylate as the toughening modifier,and methyl methacrylate and acrylic acid as the hydrophilic modifier,and copolymers were characterized by infrared spectroscopy and gel permeation chromatography.It was verified that the copolymer could cross-link with adipic dihydrazide at room temperature.(2)W/O HIPEs were prepared using copolymer/dichloromethane solution as the oil phase,adipic dihydrazide/water solution as the aqueous phase,and zinc oxide nanoparticles as the stabilizer.Cross-linked network structures were fabricated by ketone-hydrazine cross-linking reaction at room temperature to form poly HIPE.Effects of copolymer types,copolymer concentration,stabilizer content,and internal phase volume fraction on the morphology and properties of HIPEs and poly HIPEs were investigated in detail.Results showed that the crosslinking degree and mechanical properties of poly HIPEs improved with increasing the ketone carbonyl content in the copolymer.As the copolymer concentration increased,the pore size and porosity of poly HIPEs decreased,while crosslinking degree and mechanical properties improved.Although increasing stabilizer content had little impact on the crosslinking degree of poly HIPEs,it could enhance the mechanical properties and thermal stability of poly HIPEs.Increasing the internal phase volume fraction can facilitate the formation of poly HIPEs with connected pore structure,and high porosity.When the copolymer with DAAM content is 5.0wt%,copolymer concentration 15.0 w/v%,stabilizer content 3.0 w/v%,and internal phase volume fraction of 80%,the poly HIPEs were obtained with a crosslinking degree of 65.5%,Young’s modulus 1.94 MPa,pore size 4.2 μm,and porosity 91.43%.(3)In order to evaluate the feasibility of this technology on a large scale,a scale-up experiment(1 L)was successfully carried out when the copolymer with DAAM content was 5.0 wt%,copolymer concentration 10.0 w/v%,stabilizer content 3.0 w/v%,and internal phase volume fraction 75%.The crosslinking degree of the porous material was 53.6%,the same as the material created by the small trial experiment using the same formulation,proving that this method is anticipated to expand the scale of manufacturing and application of HIPE.(4)The potential applications of the resulting porous materials were investigated.The obtained poly HIPE might be applied in oil-water separation,and pollutant recovery by adsorping different chemicals,such as hexane,petroleum ether,ethanol,peanut oil,and lubricating oil.Furthermore,it could be loaded with polydimethylsiloxane at least ten times their own mass,fabricating slippery liquid-infused porous surfaces(SLIPS)with self-cleaning,and the self-compensation characteristic.