【作者】 孔祥洁；

【导师】 李丽芳；

【作者基本信息】 山东农业大学 ， 农药学， 2009， 硕士

【摘要】 随着人们对环境保护及资源有效利用的重视,农药剂型也向着高效、安全、低毒、使用方便的方向发展。农药微乳液适应了这一发展的需要,研究微乳剂温度稳定性的影响因素,可提高微乳剂配制的科学性。此外,液晶相是微乳液体系相转变过程中的一种特殊状态,形成液晶体系的界面层存在明显的粘弹性,此种具有粘弹性的乳化剂体系能形成更稳定的乳状液。本论文以毒死蜱为研究对象,在已做工作的基础上,对表面活性剂缔合结构作为药物载体进行了进一步的研究。本论文主要研究了以下几个方面的内容:1.研究了n-CnH2n+1OH(5≤n≤8)对微乳剂透明温度范围的影响。结果表明:n增大,混合表面活性剂含量增加,体系易于形成微乳;当醇种类及其含量一定时,混合表面活性剂配比对微乳剂的透明温度范围有较大影响;随醇含量增加,微乳剂的透明温度上限降低,下限略有增加;随n增大,透明温度范围上限温度基本升高,下限温度变化不规律。2.研究了电解质对毒死蜱微乳剂透明温度范围的影响。研究发现:表面活性剂含量变化会影响到微乳剂的透明温度范围;随阳离子含量增加,体系的上限温度逐渐下降,下限温度变化相对较小。随阴离子含量增加,体系上限温度整体下降,趋势与阴离子的含量及结构类型有关,体系下限温度变化无规律性;在强酸性或强碱性溶液中,体系的上限温度均下降,且在弱酸性条件下,上限温度达最大值。体系下限温度随pH值的增加缓慢升高。3.为探讨载毒死蜱液晶系形成规律,研究了有机溶剂种类、温度、正构醇碳数及无机盐对液晶相形成规律的影响。结果表明:苯(毒死蜱溶剂)环上取代基,有利于液晶“骨架”的形成及维持;高温导致液晶相形成及消失时,体系含水量均上升;随醇链的增长,体系形成液晶相所需最低含水量增加缓慢,而液晶相消失时的最高含水量则先上升后下降;添加无机盐,体系液晶相消失时所需最高含水量随阳离子水合半径降低而降低,说明液晶相结构易于破坏。4.对液晶体系稳定性进行研究,结果显示:水含量的增加导致体系浊点下降。向体系中添加醇,发现两种水分含量下(30%、50%)体系的浊点随醇链长的变化趋势基本一致,即n≤5时,体系浊点变化较小,当碳链n>5后,浊点随碳链的增长明显降低。将样品稀释至10g并进行观察,发现碳链越长稀释后的粒径越大。对含正戊醇体系,正戊醇含量增加体系浊点下降,体系稀释后的粒径先变小后增大。5.通过样品的偏光照片发现,随含水量增加体系液晶区微观结构的转变顺序为:层状及六角状—反相六角状—层状。加正戊醇体系微观结构的转变顺序不变,但转变点向含水量增加处移动。研究体系的粘度,发现粘度变化与相区转化有关,随含水的增加呈先上升后下降的趋势,高粘度出现在液晶区,最大值在含水量为33%处,此时为反六角状液晶,随后进入层状液晶区,粘度明显下降,此时体系的粘度受层间距的影响,层间距变大,粘度降低。此外,我们还研究发现25℃时含水量为50%的层状液晶体系为假塑性型流体。更多还原

【Abstract】 With great attention pay to the environmental protection and efficient use of resources, the pesticide agent producing is developing to efficient, safe, low toxic and easy-to-use. Agro-microemulsion can meet the need. Studying the factors on the transparent temperature region of agro-microemulsion, we can develop the scientific of the microemulsion preparation. In addition, liquid crystal phase is the special stage in the microemulsion phase transition, the interface layer forming liquid crystal has obviously viscoelasticity, this viscoelastic systerm can form more stable emulsion. This thesis chose chlorpyrifos as the research object. On the base of the research we have done before, we did more research about surfactant aggregates as drug carrier. The following aspects were studied in this thesis:1. Effects of n-CnH2n+1OH (5≤n≤8) on the transparent temperature region of chlorpyrifos microemulsion were investigated. The results showed that with the increasing of the n and the mixed surfactant content, the formation of microemulsion became easier;When the alcohol and its amount were known, the proportion of surfactants had a great influence on the transparent temperature region of the micro-emulsion; With the increasing of the alcohol content, the upper limit of the transparent temperature declined, and the lower limit of the transparent temperature increased slightly; With the increasing of n, the upper limit of transparent temperature increased mostly, but the changes of the lower limit of transparent temperature was in an irregular course.2. Effects of electrolytes on the transparent temperature region of chlorpyrifos micro-emulsion were investigated. The results showed that the surfactant content could influence on the transparent temperature region of micro-emulsion; Adding electrolytes found with the increasing of cationic content, the upper limit of transparent temperature of mixed systems gradually decreased,the changes of the lower limit of transparent temperature were relatively slight. With the increasing of anionic content, the upper limit of transparent temperature decreased on the whole,and the tendency was related to the anionic content and the anionic structure types,the changes of the lower limit of transparent temperature had no laws; Both in strong acid and strong base solutions, the upper limit of transparent temperature both decreased, and in weak acid solutions the upper limit of transparent temperature reached a maximum. With the increasing of pH values, the lower limit of transparent temperature increased slightly.3. Effects of organic solvents, temperature, n-alcohols and inorganic salt on the formation of liquid crystal phase were investigated to discuss the formation law of liquid crystal system loading chlorphyrifos. The results showed that the substituent in the phenyl ring was advantageous to the formation and maintenance of liquid crystal phase; The system water content rose when the liquid crystalline phase formed and vanished caused by high temperature; With the increasing of the chain length for n-alcohols, the minimum water content for the formation of liquid crystal increased slowly. But when the liquid crystal phase vanished, the maximum water content first rose, then dropped; Adding inorganic salt, the maximum water content needed for the disappearance of liquid crystal phase decreased with hydrated radius of positive ion decreasing, it showed that structure of liquid crystal was unstable.4. Effects of stability of liquid crystal phase were investigated. The results showed that with the increasing of water content, the cloud point of system decreased; Adding n-CnH2n+1OH to the system, cloud point changed similarly with the changes of chain length under the different water content (30%、50%), that was to say when n less than or equal to 5, the changes of cloud point was less, but when n more than 5, the cloud point significantly decreased with the increasing of the chain length for n-alcohols. Diluted the sample to 10g and it was observed that after diluting the particle size of the emulsion increased with the increasing of the chain length for n-alcohols. For the system which contained n-pentanol, the cloud point decreased with the increasing of n-pentanol content, and the particle size of the emulsion after diluted first dropped, then rose.5. By the investigation on the polarizing photos could find that with the water content increasing, the order of liquid crystal microstructure was lamellar liquid crystal and hexagonal liquid crystal; reversed phase hexagonal liquid crystal; lamellar liquid crystal. Adding n-pentanol, the convert order of liquid crystal microstructure did not change, but the convert point moved to the area containing more water. By researching the viscosity of the system, we found the change of viscosity had close relationships with the change of liquid crystal microstructure, with the increasing of the water content the viscosity first rose, then dropped, the high viscosity areas is in the liquid crystal phase. When the water content was 33%, the viscosity of system is the highest, its microstructure is reversed phase hexagonal liquid crystal, then the system came into lamellar liquid crystal, the viscosity significantly decreased. In the lamellar liquid crystal phase, the viscosity had close relationships with the spacing of layers, the viscosity decreased when the spacing of layers increased. Moreover, we found that, the lamellar liquid crystal system which contains 50% water in 25℃was pseudoplastic fluid.更多还原