【作者】 田鹏飞；

【导师】 刘温霞；

【作者基本信息】 山东轻工业学院 ， 制浆造纸工程， 2008， 硕士

【摘要】 本论文以无机多功能材料层状双羟基金属复合氧化物-氢氧化镁铝(MAH)为微粒乳化剂,研究其单独使用及辅以其他物质时,对液体石蜡、苯及松香苯溶液的乳化与稳定作用规律。MAH微粒能够将液体石蜡/水体系乳化成O/W型乳状液,且随着初始油相体积分数和MAH用量的增大,乳状液稳定性提高,粘度也随之增加,但分散液滴分别表现为增大和减小趋势。柠檬酸钠对MAH的凝聚作用能够促进其在油水界面上的聚集,形成的高粘度松散聚集体有助于提高石蜡乳状液稳定性,乳状液的粘度也随之提高。但柠檬酸钠用量过大而引起MAH的失水凝聚时,不利于乳状液的稳定,液滴直径也急剧增大。钠化膨润土对MAH的异凝聚作用也能够促进其在油水界面的吸附,少量的钠化膨润土即可显著提高石蜡乳状液的稳定性,但乳状液粘度和液滴也随之增大。MAH微粒能够将苯/水体系完全乳化成O/W型乳状液,但苯乳液稳定性相当差,加入较高量的MAH也不能有效改善苯乳液的稳定性。松香溶于苯后,可以形成具有一定极性的松香苯溶液,导致MAH微粒在油水界面上由“亲水型”转变为“亲油型”,且松香浓度越大,溶液极性越强,MAH三相接触角也越大。结果,苯溶松香溶液均被MAH微粒乳化成W/O型乳状液,且具有较高的稳定性。乳状液稳定性随着油相极性的增强和初始水相体积分数的增大而提高,粘度和分散液滴也随之增大,仅需微量的MAH微粒便可获得稳定的苯溶松香乳状液。MAH用于乳化50wt%的极性松香苯溶液时,形成W/O型乳状液。在较低的初始油水体积比例下,少量的MAH更有利于制备稳定的苯溶松香乳状液。MAH用量过大时,乳状液稳定性反而降低。随着MAH用量的增加,乳状液粘度先增大后减小,分散液滴则一直减小。乳化过程中分散强度的提高可在一定程度上提高乳状液的稳定性,并使分散液滴尺寸减小。无机盐NaCl的存在有利于促进MAH粒子间的凝聚,但这不利于苯溶松香乳状液的稳定,凝聚作用越强,乳状液稳定性越差,粘度却随之变大,液滴变小。水溶性聚合物电解质非离子聚丙烯酰胺和羟乙基纤维素及非离子和弱阳离子有机微粒均可以将苯溶松香溶液/水体系乳化成O/W型乳状液。MAH分别与聚合物电解质和有机微粒联合使用乳化松香苯溶液时,在初始油水体积比为1:2的情况下,调整MAH与复配物的相对用量,可以获得两种类型的乳状液,且在合适的用量下,二者的共同作用能够提高乳状液的稳定性,但W/O型乳状液稳定性较好。更多还原

【Abstract】 The emulsifying and stablilizing effects of layered double hydroxides——magnesium aluminum hydroxides (MAH) on liquid paraffin, benzene and rosin solutions as a microparticle emulsifier either alone or together with other adjuvants were investigated systematically.Liquid paraffin/water can be emulsified into o/w emulsion by MAH when initial oil and water volume fraction was less than 3:1. The stability of paraffin emulsion was improved by increasing paraffin volume fraction and MAH addition level, accompanied by the increase of emulsion viscosity. However, the droplet size increased with increasing paraffin volume fraction while decreased with increasing MAH addition level. Sodium citrate can induce the aggregation of MAH particles and improve the adsorption of MAH on the paraffin/water interface. The formed open aggregates with high viscosity may improve the stability of the MAH stabilized paraffin/water emulsion. However, the emulsion viscosity was also increased. When the addition level of sodium citrate was too large, denser MAH aggregates were formed and the stability of paraffin-in-water emulsion was lowered while the emulsion droplet size was rapidly increased. Sodium-activated bentonite can induce the coagulation of MAH and improve the adsorption of MAH on the paraffin/water interface. Small amount of bentonite can improve the stability of paraffin/water emulsion prominently; meanwhile, the viscosity and droplet size were also increased.Benzene/water can be emulsified into o/w emulsion by MAH, but the stability of benzene emulsion was poor even at large addition levels of MAH. However, when rosin was dissolved in benzene, the polarity of oil phase and three-phase contact angle of MAH were enhanced. As result, the hydrophilic MAH displayed a hydrophobic nature at the oil/water interface, and w/o emulsions with excellent stability were formed. The emulsion stability was improved by increasing the rosin concentration of oil phase and the initial water volume fraction, accompanied by the increase of emulsion viscosity and droplet size. Meanwhile, the stable water-in- rosin solution could be obtained by adding a small amount of MAH particles.Rosin solution, which was prepared by dissolving rosin in benzene at mass ratio of 1:1, could be emulsified into a stable w/o emulsion by MAH. The emulsion stability could be further improved with increasing the initial water volume fraction and addition level of MAH while the emulsion viscosity was increased and the droplet size was decreased. However, the too large dosage of MAH was harmful to the stability of emulsion. During the emulsifying process, the higher mechanical force led to more stable emulsion with smaller droplets. The aggregation of MAH particles caused by NaCl was adverse to the stability of emulsion. Increasing salt concentration lowered the emulsion stability, increased the emulsion viscosity and decreased the emulsion droplet size.The water-soluble polymer (WSP) and organic microparticles (OMP) favored to stabilize w/o emulsions when 50wt% rosin solution was used as oil phase. When the MAH and WSP or OMP were used together, different types of rosin emulsion could be obtained by adjusting the relative amount of MAH and WSP or OMP at the initial oil-water volume fraction of 1:2. The emulsion stability was also enhanced by the co-emulsifying effect of MAH and WSP or OMP at suitable addition levels. Generally speaking, the rosin solution-in-water emulsion was more stable.更多还原