【摘要】：納米限域下,由于所使用的多孔材料孔道結(jié)構(gòu)不同,小尺寸效應(yīng)、界面作用對(duì)正烷醇在孔道內(nèi)的相行為有明顯的影響。正烷醇在孔內(nèi)的相變溫度、相變焓和存在狀態(tài)均隨著孔徑尺寸和孔壁的作用而發(fā)生變化。實(shí)驗(yàn)過程中使用的多孔材料有硅膠(SG)、多孔玻璃(CPG)以及SBA-15,將有機(jī)液體通過物理方法與其吸附,使有機(jī)液體與多孔材料的孔壁產(chǎn)生或弱、中等或強(qiáng)的相互作用模式。所用檢測(cè)的基本手段為低溫DSC量熱法,研究在12 nm-300 nm孔徑范圍內(nèi)有序和無序多孔材料內(nèi)正烷醇的熔點(diǎn)、凝固點(diǎn)、相變焓等隨孔徑尺寸、孔道結(jié)構(gòu)的變化規(guī)律。最后以XRD射線掃描作為輔助手段,根據(jù)標(biāo)準(zhǔn)譜圖分析正烷醇標(biāo)準(zhǔn)狀態(tài)已經(jīng)在納米限域下的晶型變化,判斷在各種界面作用下其熱力學(xué)性質(zhì)與多孔材料尺寸大小的關(guān)系。為研究納米材料的制備、納米藥物的運(yùn)輸和理解低維液體的性質(zhì)提供了熱力學(xué)基礎(chǔ)。本實(shí)驗(yàn)的主要工作如下:(1)利用融溶法將正烷醇和多孔材料通過一定的質(zhì)量比例混合,然后放置在設(shè)置溫度高于正烷醇熔點(diǎn)的鼓風(fēng)干燥箱內(nèi),使其融化吸附進(jìn)入多孔材料內(nèi)部,制備CnOH(n=16,18)在不同多孔材料內(nèi)的相變材料。(2)用差示掃描量熱儀(DSC)檢測(cè)該材料在常規(guī)狀態(tài)下以及吸附在尺寸不同的孔道內(nèi)部之后的熱力學(xué)性質(zhì),觀察升降溫相變規(guī)律,探究隨孔徑變化的差異。結(jié)果是隨著孔徑的減小,相變溫度和相變焓都會(huì)隨著降低。(3)利用DSC和XRD得出的結(jié)果繪制變化圖,分析結(jié)果后,可以得出正烷醇在大孔徑的CPG(300 nm)和SG(200 nm)中分子排列順序在一定程度上保持著與常規(guī)狀態(tài)下相似較規(guī)整的結(jié)構(gòu),但是在小孔徑CPG(12 nm)和SG(15 nm)中得排列順序被打亂出現(xiàn)新的結(jié)構(gòu)。主要可能是由于多孔材料的尺寸效應(yīng)和表面效應(yīng)的作用。(4)本實(shí)驗(yàn)探究的是偶數(shù)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變行為。在孔內(nèi)相變峰被分離,固-液相變溫度比固-固相變溫度降低速率較慢,各物質(zhì)的相變溫度由于孔壁的特性和極性的差異發(fā)生不同程度的降低,且在小孔徑孔材料內(nèi)由于孔道結(jié)構(gòu)和尺寸效應(yīng)會(huì)出現(xiàn)新的轉(zhuǎn)動(dòng)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.
【學(xué)位授予單位】：山東農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB34

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本文編號(hào)：2289034