Preparation Of Hydrophobic And Oleophilic Organic-Inorganic Composite Emulsion And Its Application To Water/Oil Separation Filter Paper

With the development of automobile industry and the increasingly strict regulation for automobile exhaust, high quality fuel oil is in great demand. The quality of fuel oil is responsibly for the daily operation of the automobile and has great impact on the life span and service efficiency of the engine. Water is most common pollutant in fuel oil which could jeopardize the quality of fuel oil and bring damage to the components of the engine. Therefore, the separation of water from fuel oil is necessary. Among many oil/water separating methods, coalescence separating technology is the most widely used method for its large processing capacity and low cost. By making use of the difference of surface tension between water and fuel oil, the filter cartridge made of porous filter material with excellent hydrophobicity and oleophilicity properties allows the fuel oil to penetrate through while water droplets are held up and therefore oil/water separation can be achieved. Filter paper made of natural fiber is the most commonly used separating filter material in automobile industry for its unique advantages such as low density and low price. In this paper, we aim at the preparation of an organic-inorganic composite emulsion with excellent hydrophobic and oleophilic properties, the filter paper coated by the composite emulsion is supposed to present excellent mechanical strength and highly hydrophobic/oleophilic properties and therefore can be used as oil/water separation material. In order to achieve this goal, our studies focus on the following aspects:Poly-styrene-acryalte emulsion was prepared by emulsion polymerization method. Effects of polymerization process?amount of buffer agent?dosage of surfactants?dosage of initiator?stirring speed and reaction temperature on the stability of emulsion polymerization were studied. Effects of the Tg of copolymer, dosage of functional monomer AA and crosslinking monomer N-MA on the mechanical strength of filter paper were investigated. The results show that Poly-styrene-acrylate emulsion with excellent Ca²⁺, centrifugal and mechanical stability can be obtained by optimizing polymerization technique and conditions. The emulsion coated filter paper shows excellent mechanical properties such as stiffness, sheet burst strength, tensile strength and air permeability. The emulsion coated filter paper preserves porous structure and therefore maintains excellent filter efficiency of the filter paper.Fluorinated poly-styrene-acrylate latex particles with core-shell structure were prepared by seeded semi-continuous emulsion polymerization. Effects of fluorine monomers with different length of fluorine-carbon chain?core-shell monomer weight ratio?fluorine monomer content and octadecyl acrylate to the wetting behavior of the copolymer film was studied. The results show that when using the fluorine monomer DFMA?the core-shell monomer weight ratio is 8:2 and the fluorine monomer content is 40.0wt% of the shell monomer, the copolymer film shows excellent hydrophobic and oleophilic properties. The copolymerization of octadecyl acrylate can enhance the oleophilicty of the copolymer film.Effects of surfactants to the morphology of latex particles, effects of crosslinking structure and silicon to the wetting behavior of the copolymer film were investigated. The results suggest that latex particles prepared by reactive surfactant presents a core-shell structure while latex particles prepared by regular surfactant presents a snow-man structure, the copolymer film of the core-shell structured latex particle show better water repellency. The crosslinking structure of the latex particles is in favor of a uniform core-shell structure and the copolymer film shows better water repellency due to the fact that fluorinated copolymer can be fixed on the surface of the copolymer film. The combination of silicon is in favor of the migration of the fluorine groups and siloxane itself to the air-film interface and therefore the hydrophobicity of the copolymer film is increased. Influence of the film formation temperature and post-treatment temperature to the hydrophobicity of the copolymer film were studied. The results shows when the film formation temperature is 80?and 165?post-treatment can further enhance the hydrophobicity of the copolymer film. The prepared emulsion was applied to the filter paper and the coated paper shows excellent hydrophobicity/oleophilicty and high oil-water separation efficiency.Nano SiO₂ sol solution was prepared by sol-gel method using TEOS and MTES as precursors. The result indicated that the first prepared highly dispersed SiO₂ particles turn into rasp-like particles with nano-micro-binary structure due to the self-assemble effect of the SiO₂ sol during aging process. The morphology of SiO₂ particles could keep stable by modifying the raspberry-like SiO₂ with DTMS or F8261. Effect of the morphology of SiO₂ particles to the wetting behavior of the SiO₂ film was studied by WCA, AFM and SEM. The results show that film of raspberry-like SiO₂ particles presents superhydrophibic/superoleophilic properties due to the nano-micro-binary structure of raspberry-like SiO₂ particles. The mixture of fluorinated emulsion and raspberry-like SiO₂ particles were applied to the filter paper, when the SiO₂ content reaches 50.0wt%, the filter paper shows superhydrophobic and superoleophilic properties and water separation efficiency can be as high as 99.50wt%.Cationic fluorinated poly-styrene-acrylate emulsion was prepared using cationic surfactant. Soap-free fluorinated poly-styrene-acrylate emulsion was prepared by using water soluble cationic monomer DMC and ethanol as co-solvent. The ? potential of the eumlsion and nano-SiO₂ particles was controlled by adjusting their pH value. Organic-organic composite particles can be obtained due to the self-assemble effect between the two systems. The results shows that composite latex particles made of cationic emulsion and nano-SiO₂ particles is unstable due to the fact that cationic surfactant on the surface of the latex particles was absorbed by nano-SiO₂ particles. While composite latex particles made of soap-free cationic emulsion and nano-SiO₂ particles is stable due to the static effect and condensation of hydrogen between the two systems. The surface of the organic-inorganic composite emulsion coating shows a nano rough structure. When the organic-inorganic emulsion was applied to the filter paper, the coated filter paper shows superdrophobic and superoleophilic properties and the water/oil separation efficiency and be as high as 99.6wt%.