纳米限域下十六醇和十八醇的相行为研究
发布时间：2018-10-23 10:59
【摘要】：纳米限域下,由于所使用的多孔材料孔道结构不同,小尺寸效应、界面作用对正烷醇在孔道内的相行为有明显的影响。正烷醇在孔内的相变温度、相变焓和存在状态均随着孔径尺寸和孔壁的作用而发生变化。实验过程中使用的多孔材料有硅胶(SG)、多孔玻璃(CPG)以及SBA-15,将有机液体通过物理方法与其吸附,使有机液体与多孔材料的孔壁产生或弱、中等或强的相互作用模式。所用检测的基本手段为低温DSC量热法,研究在12 nm-300 nm孔径范围内有序和无序多孔材料内正烷醇的熔点、凝固点、相变焓等随孔径尺寸、孔道结构的变化规律。最后以XRD射线扫描作为辅助手段,根据标准谱图分析正烷醇标准状态已经在纳米限域下的晶型变化,判断在各种界面作用下其热力学性质与多孔材料尺寸大小的关系。为研究纳米材料的制备、纳米药物的运输和理解低维液体的性质提供了热力学基础。本实验的主要工作如下:(1)利用融溶法将正烷醇和多孔材料通过一定的质量比例混合,然后放置在设置温度高于正烷醇熔点的鼓风干燥箱内,使其融化吸附进入多孔材料内部,制备CnOH(n=16,18)在不同多孔材料内的相变材料。(2)用差示扫描量热仪(DSC)检测该材料在常规状态下以及吸附在尺寸不同的孔道内部之后的热力学性质,观察升降温相变规律,探究随孔径变化的差异。结果是随着孔径的减小,相变温度和相变焓都会随着降低。(3)利用DSC和XRD得出的结果绘制变化图,分析结果后,可以得出正烷醇在大孔径的CPG(300 nm)和SG(200 nm)中分子排列顺序在一定程度上保持着与常规状态下相似较规整的结构,但是在小孔径CPG(12 nm)和SG(15 nm)中得排列顺序被打乱出现新的结构。主要可能是由于多孔材料的尺寸效应和表面效应的作用。(4)本实验探究的是偶数碳正十六烷醇(C_(16)OH)和正十八烷醇(C_(18)OH)在不同多孔材料中的相变行为。在孔内相变峰被分离,固-液相变温度比固-固相变温度降低速率较慢,各物质的相变温度由于孔壁的特性和极性的差异发生不同程度的降低,且在小孔径孔材料内由于孔道结构和尺寸效应会出现新的转动相。
[Abstract]:Due to the different pore structure and small size effect, the interfacial interaction has a significant effect on the phase behavior of n-alkanol in the pore channel. The phase transition temperature, enthalpy and state of phase transition of n-alkanol in the pore vary with the pore size and pore wall. The porous materials used in the experiment include silica gel (SG), porous glass (CPG) and SBA-15, to adsorb organic liquid through physical method with which the pore wall of organic liquid and porous material can be produced or weak medium or strong interaction mode. The basic detection method is low temperature DSC calorimetry. The changes of melting point, solidification point, phase transition enthalpy of n-alkanol in ordered and disordered porous materials with pore size and pore structure are studied in the range of 12 nm-300 nm pore size. Finally, using XRD ray scanning as an auxiliary means, according to the standard spectrum analysis of n-alkanol standard state in the nanocrystalline limit, the relationship between the thermodynamic properties and the size of porous materials under various interface actions is determined. It provides a thermodynamic basis for the preparation of nanomaterials, the transport of nanopharmaceuticals and the understanding of the properties of low dimensional liquids. The main work of this experiment is as follows: (1) the n-alkanol and porous materials are mixed by a certain mass ratio by the method of melt solution, and then placed in the blast drying box where the temperature is higher than the melting point of n-alkanol, so that it melts and adsorbs into the porous material. The phase change materials of CnOH (nf16 ~ (18) were prepared in different porous materials. (2) the thermodynamic properties of the materials were examined by differential scanning calorimetry (DSC), and the thermodynamics properties of the materials were observed after adsorption in the inner channels of different sizes, and the law of phase transition was observed. Explore differences with aperture. The results show that the phase transition temperature and enthalpy decrease with the decrease of pore size. (3) using the results obtained by DSC and XRD, the change diagram is drawn, and the results are analyzed. It can be concluded that the molecular order of n-alkanol in large pore size CPG (300 nm) and SG (200 nm) is similar to that in normal state to some extent, but in small pore CPG (12 nm) and SG (15 nm), the new structure appears. It is possible that the effect of size effect and surface effect of porous materials. (4) the phase transition behavior of even carbon hexadecanol (C _ (16) OH) and octadecanol (C _ (18) OH) in different porous materials is investigated in this experiment. When the phase transition peak is separated in the pore, the temperature of solid-liquid phase change is slower than that of the temperature of solid-solid phase change, and the phase transition temperature of each material decreases in varying degrees due to the difference of pore wall characteristics and polarity. And a new rotating phase will appear in the small pore material due to the pore structure and size effect.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34
[Abstract]:Due to the different pore structure and small size effect, the interfacial interaction has a significant effect on the phase behavior of n-alkanol in the pore channel. The phase transition temperature, enthalpy and state of phase transition of n-alkanol in the pore vary with the pore size and pore wall. The porous materials used in the experiment include silica gel (SG), porous glass (CPG) and SBA-15, to adsorb organic liquid through physical method with which the pore wall of organic liquid and porous material can be produced or weak medium or strong interaction mode. The basic detection method is low temperature DSC calorimetry. The changes of melting point, solidification point, phase transition enthalpy of n-alkanol in ordered and disordered porous materials with pore size and pore structure are studied in the range of 12 nm-300 nm pore size. Finally, using XRD ray scanning as an auxiliary means, according to the standard spectrum analysis of n-alkanol standard state in the nanocrystalline limit, the relationship between the thermodynamic properties and the size of porous materials under various interface actions is determined. It provides a thermodynamic basis for the preparation of nanomaterials, the transport of nanopharmaceuticals and the understanding of the properties of low dimensional liquids. The main work of this experiment is as follows: (1) the n-alkanol and porous materials are mixed by a certain mass ratio by the method of melt solution, and then placed in the blast drying box where the temperature is higher than the melting point of n-alkanol, so that it melts and adsorbs into the porous material. The phase change materials of CnOH (nf16 ~ (18) were prepared in different porous materials. (2) the thermodynamic properties of the materials were examined by differential scanning calorimetry (DSC), and the thermodynamics properties of the materials were observed after adsorption in the inner channels of different sizes, and the law of phase transition was observed. Explore differences with aperture. The results show that the phase transition temperature and enthalpy decrease with the decrease of pore size. (3) using the results obtained by DSC and XRD, the change diagram is drawn, and the results are analyzed. It can be concluded that the molecular order of n-alkanol in large pore size CPG (300 nm) and SG (200 nm) is similar to that in normal state to some extent, but in small pore CPG (12 nm) and SG (15 nm), the new structure appears. It is possible that the effect of size effect and surface effect of porous materials. (4) the phase transition behavior of even carbon hexadecanol (C _ (16) OH) and octadecanol (C _ (18) OH) in different porous materials is investigated in this experiment. When the phase transition peak is separated in the pore, the temperature of solid-liquid phase change is slower than that of the temperature of solid-solid phase change, and the phase transition temperature of each material decreases in varying degrees due to the difference of pore wall characteristics and polarity. And a new rotating phase will appear in the small pore material due to the pore structure and size effect.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34
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