【作者】 徐桂龙；

【导师】 杨卓如；

【作者基本信息】 华南理工大学 ， 化学工程， 2011， 博士

【摘要】 随着现代汽车工业的飞速发展和政策法规对汽车尾气排放的要求越来越严格,汽车对燃油的品质要求也越来越高。燃油对发动机的正常运转起着决定性的作用,其品质的优劣直接影响到发动机的工作状态和汽车行驶性能。水是油液中最为普遍的污染物,是导致油液品质下降的主要原因,并且直接威胁到汽车元件和系统的安全运行。因此,高效的脱水技术对提高燃油品质,乃至对整个汽车行业的发展具有重要意义。在众多的油水分离技术中,聚结分离因其处理量大、造价低等优点而得到广泛应用,其分离机理是利用油水两相表面能的差异,采用具有表面疏水亲油的多孔料制成分离滤芯,可使油液顺利通过,而水滴被有效地被拦截在滤芯外面,从而实现高效脱水。植物纤维基材过滤滤纸由于存在着质地轻、成本低、体积小等优点而成为汽车发动机滤清器中最常用的分离介质。本课题旨在制备一种具有优良疏水亲油性能的水性树脂,通过有机无机复合的方法制备高效的油水分离树脂并应用于滤纸浸渍,在给予滤纸以高效的油水分离性能同时,大大提高了滤纸强度性能与使用寿命。为此,本文主要工作内容如下:首先,考察了聚合工艺、缓冲剂用量、乳化剂用量及配比、引发剂用量、搅拌速度等因素对苯丙乳液聚合过程稳定性的影响;研究共聚物玻璃化转变温度,功能单体AA（丙烯酸）,交联单体N-MA（N-羟甲基丙烯酰胺）对浸渍乳液后滤纸强度性能的影响。结果表明,通过工艺的优化,可以制备具有优良的Ca2+、离心和机械稳定性的苯丙乳液。苯丙乳液浸渍后的滤纸具有优良的耐破度、挺度、抗张强度和抗水性等性能,乳液成膜后包裹在纤维表面以及纤维的交织点,并未堵塞纤维孔隙,保持滤纸优良的过滤性能。在苯丙乳液体系的基础上,制备了以苯丙共聚物为核、含氟共聚物为壳的核壳结构含氟苯丙乳液。考察了氟单体种类、核壳单体质量比例、壳单体有机氟含量和丙烯酸十八酯对制备乳液涂膜疏水亲油性的影响。结果表明,选用氟碳链链长为6的含氟单体、核壳单体比例为8:2且和壳单体有机氟含量为40.0wt%时,制备的共聚物涂膜具有较好的疏水亲油性,丙烯酸十八酯参与共聚有利于提高共聚物乳液涂膜的亲油性。研究乳化剂体系和交联体系对制备乳液乳胶粒形貌和乳液涂膜润湿性能的影响。发现在实验条件下,聚合型乳化剂制备的乳胶粒呈现核壳结构,而常规烷烃乳化剂制备乳液乳胶粒呈现雪人型结构,核壳结构的乳液涂膜比雪人型结构的乳液涂膜具有更优良的疏水性;分子内交联的方法有利于乳液聚合过程中形成正相的核壳结构乳胶粒,同时可以抑制共聚物涂膜处在极性条件下,非极性基团向涂膜内部迁移的趋势,从而保持氟聚合物涂膜优异的表面疏水性质。利用氟硅共聚合共迁移的特性,将有机硅单体参与共聚,进一步提高共聚物涂膜的性能。考察乳液成膜温度和涂膜后处理方法对乳液涂膜表面润湿性能的影响,发现乳液在80℃成膜,再经过165℃退火处理后涂膜具有优良的疏水性。将制备的氟硅改性苯丙乳液应用于滤纸浸渍,并研究其油水分离过程,发现油水分离精度随着滤纸疏水亲油性的提高而提高,油水分离效率最高可以达到98.5wt%。采用溶剂凝胶法,以TEOS（正硅酸乙酯）和MTES（甲基三乙氧基硅烷）为前躯体制备疏水SiO₂溶胶。发现SiO₂溶胶在陈化过程中,纳米SiO₂粒子由于自组装作用发生团簇,然后形成具有微米-纳米双微观结构的草莓状SiO₂粒子。通过调节SiO₂溶胶的陈化时间可控制SiO₂粒子形貌,对SiO₂粒子表面进行改性,可使SiO₂粒子形貌保持长期稳定。利用WCA（水接触角）、AFM（原子力显微镜）和SEM（扫描电镜）等测试手段来表征SiO₂粒子涂膜表面微观结构、表面粗糙度和疏水性能之间的关系。结果表明:草莓状SiO₂粒子涂膜具有超疏水/超亲油性能,这是由于疏水草莓状粒子所具有的特殊纳米-微米多微观尺度结构,使粒子涂膜的润湿行为服从Cassie润湿行为。将氟硅改性苯丙乳液与草莓状SiO₂粒子共同应用于过滤滤纸,当SiO₂粒子的质量比例达到树脂的50.0wt%时,浸渍滤纸可以达到超疏水/超亲油性能,油水分离效果最高可达99.5wt%。以阳离子乳化剂CTAB（十六烷基三甲基溴化铵）与非离子乳化剂OP-10（辛基酚聚氧乙烯醚）为复合乳化剂体系制备普通阳离子乳液。通过阳离子水溶性单体DMC（甲基丙烯酰氧乙基三甲基氯化铵）与增溶剂乙醇的共同作用制备无皂阳离子乳液。通过调节体系pH值控制乳液和nano-SiO₂粒子的（?）电位处于适当的范围,利用乳胶粒和nano-SiO₂粒子之间的相反电荷的静电自组装作用形成有机无机复合乳液。结果表明:普通阳离子乳液和nano-SiO₂粒子的复合体系由于两相对乳化剂的吸附竞争,造成乳胶粒表面乳化剂平衡被破坏,复合体系不稳定。无皂阳离子乳液与nano-SiO₂粒子之间则可以通过两相间静电自组装和羟基缩合作用,得到稳定的有机无机复合乳液。有机无机复合乳液成膜后,nano-SiO₂粒子能够凸显在涂膜表面,形成纳米粗糙形貌。过滤滤纸经有机无机复合乳液浸渍后,滤纸表面呈现双微观粗糙结构,赋予滤纸超疏水/超亲油性能,油水分离率可以高达99.6wt%。更多还原

【Abstract】 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%.更多还原