納米纖維膜負(fù)載脂肪酸定形相變材料的結(jié)構(gòu)與性能
發(fā)布時(shí)間：2018-08-28 06:05
【摘要】：能源的合理利用和新能源的開發(fā)一直是人們關(guān)注的焦點(diǎn),欲緩解能源緊缺、能源消費(fèi)快速增長(zhǎng)與環(huán)境污染之間的諸多矛盾,利用相變材料的相變潛熱進(jìn)行能量的存儲(chǔ)與釋放是一項(xiàng)新型環(huán)保節(jié)能技術(shù),可以以此來(lái)控制體系或環(huán)境的溫度,具有熱能儲(chǔ)存和溫度調(diào)控的功能。脂肪酸是一類重要的固-液相變材料,具有儲(chǔ)熱密度大、相變過(guò)程溫度恒定等優(yōu)點(diǎn)而備受關(guān)注,但存在相變體積變化大和熱傳導(dǎo)性低等缺點(diǎn)。然而,靜電紡無(wú)機(jī)納米纖維具有較高的比表面積、獨(dú)特的網(wǎng)絡(luò)結(jié)構(gòu)、豐富的孔隙率和高的熱傳導(dǎo)系數(shù)等優(yōu)異特點(diǎn)可用作固-液相變材料的支撐材料,有效解決了脂肪酸相變過(guò)程的滲漏現(xiàn)象和低的熱傳導(dǎo)性問(wèn)題。因此納米纖維膜負(fù)載脂肪酸定形相變材料的制備與結(jié)構(gòu)性能研究成為重要的研究方向。本文以癸酸(CA)、月桂酸(LA)、肉豆蔻酸(MA)、棕櫚酸(PA)和硬脂酸(SA)為原料,利用熔融混合和超聲分散的方法制備了CA系二元脂肪酸低共熔物(CA-LA,CA-MA,CA-PA和CA-SA)和CA-LA-PA三元脂肪酸低共熔物,并用作相變材料。結(jié)合溶膠-凝膠、靜電紡絲和高溫煅燒等原理與技術(shù),制備了Si O2納米纖維和Ti O2摻雜Si O2(Ti O2/Si O2)納米纖維,并用作支撐材料。然后利用納米纖維膜物理吸附脂肪酸的方法制備了復(fù)合定形相變材料,對(duì)其結(jié)構(gòu)形貌和性能進(jìn)行了研究。其主要研究?jī)?nèi)容可分為以下三部分:1.制備了PVP/Si O2復(fù)合納米纖維,利用TGA研究了其熱降解過(guò)程,然后經(jīng)500oC、600oC和700oC三種不同溫度煅燒處理,制得Si O2納米纖維,采用FT-IR對(duì)其組成成分和官能團(tuán)變化進(jìn)行了表征,證實(shí)了Si O2納米纖維的形成。對(duì)比分析了不同煅燒溫度下Si O2納米纖維對(duì)亞甲基藍(lán)染料和CA-LA-PA三元脂肪酸低共熔物的吸附性能,結(jié)果表明經(jīng)600oC煅燒制得的多孔網(wǎng)絡(luò)結(jié)構(gòu)Si O2納米纖維具有較高的吸附容量。2.利用XRD和SEM對(duì)Si O2納米纖維的結(jié)構(gòu)形貌進(jìn)行了進(jìn)一步的表征,結(jié)果顯示Si O2納米纖維具有無(wú)定形的結(jié)構(gòu),且纖維表面粗糙、部分地方出現(xiàn)粘連。通過(guò)SEM、吸附性能、DSC及自組裝熱性能測(cè)試儀對(duì)制備的Si O2基復(fù)合定形相變材料的形貌結(jié)構(gòu)、吸附容量、儲(chǔ)熱性能及熱能儲(chǔ)存/釋放性能進(jìn)行了研究,結(jié)果表明二元脂肪酸低共熔物較好的分散在Si O2納米纖維的多孔網(wǎng)絡(luò)結(jié)構(gòu)中,歸因于脂肪酸與Si O2之間的毛細(xì)管效應(yīng)和表面張力作用。同時(shí),復(fù)合定形相變材料具有適宜的相變溫度和較高的熱焓值,且靜電紡Si O2納米纖維改善了復(fù)合定形相變材料的熱能儲(chǔ)存/釋放速率。3.以鈦酸正丁酯(TBT)和正硅酸四乙酯(TEOS)為前驅(qū)體,通過(guò)靜電紡絲和高溫煅燒制備了Ti O2摻雜Si O2(Ti O2/Si O2)納米纖維。采用FT-IR、XRD和SEM對(duì)三種煅燒溫度(600oC、900oC和1200oC)下制得Ti O2/Si O2納米纖維的成分、晶型結(jié)構(gòu)和形貌進(jìn)行了表征,結(jié)果顯示隨著煅燒溫度的升高,Ti O2/Si O2納米纖維由600oC時(shí)的無(wú)定形結(jié)構(gòu)轉(zhuǎn)變?yōu)?200oC時(shí)的晶型結(jié)構(gòu),纖維的形貌也由600oC時(shí)的均勻且表面光滑的圓柱形變?yōu)?200oC時(shí)的鈣化狀。此外,通過(guò)SEM、吸附性能和DSC對(duì)不同熱處理溫度下制得Ti O2/Si O2基復(fù)合定形相變材料的形貌結(jié)構(gòu)、吸附容量和熱性能進(jìn)行了對(duì)比研究,研究結(jié)果表明二元脂肪酸低共熔物較均勻地分散在Ti O2/Si O2納米纖維的多孔網(wǎng)絡(luò)結(jié)構(gòu)中,隨著煅燒溫度的升高,Ti O2/Si O2納米纖維的結(jié)構(gòu)形貌變化致使其對(duì)二元脂肪酸低共熔物的吸附容量下降,導(dǎo)致復(fù)合定形相變材料的熱能存儲(chǔ)性能降低。
[Abstract]:The rational use of energy and the development of new energy sources have always been the focus of attention. In order to alleviate the contradiction between energy shortage, rapid growth of energy consumption and environmental pollution, the use of latent heat of phase change materials for energy storage and release is a new environmental protection and energy-saving technology, which can be used to control the temperature of the system or environment. Fatty acids are a kind of important solid-liquid phase change materials, which have the advantages of high heat storage density and constant temperature during phase change process. However, they have the disadvantages of large phase change volume change and low thermal conductivity. However, electrospun inorganic nanofibers have high specific surface area and unique network junction. Structures, abundant porosity and high thermal conductivity can be used as support materials for solid-liquid phase change materials, which can effectively solve the leakage and low thermal conductivity problems in fatty acid phase change process. CA binary fatty acid eutectics (CA-LA, CA-MA, CA-PA and CA-SA) and CA-LA-PA ternary fatty acid eutectics were prepared by melt mixing and ultrasonic dispersion using decanoic acid (CA), lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA) as raw materials and used as phase change materials. SiO_2 nanofibers and TiO_2-doped SiO_2 (TiO_2/SiO_2) nanofibers were prepared by calcination and used as supporting materials. Then the composite phase change materials were prepared by the method of physical adsorption of fatty acids on nanofibers. The morphology and properties of the composite phase change materials were studied. The PVP/Si O2 composite nanofibers were prepared. The thermal degradation process was studied by TGA. Then the Si O2 nanofibers were prepared by calcination at 500oC, 600oC and 700oC. The composition and functional groups of the nanofibers were characterized by FT-IR. The formation of Si O2 nanofibers at different calcination temperatures was compared and analyzed. The adsorption properties of nanofibers for methylene blue dye and CA-LA-PA ternary fatty acid hypoeutectic were studied. The results showed that the porous network Si O2 nanofibers prepared by calcination at 600oC had higher adsorption capacity. 2. The structure and morphology of Si O2 nanofibers were further characterized by XRD and SEM. The results showed that Si O2 nanofibers had good adsorption properties. The morphology, adsorption capacity, thermal storage and thermal energy storage/release properties of SiO2-based composite phase change materials were studied by means of SEM, adsorption properties, DSC and self-assembled thermal performance tester. The results showed that the binary fatty acid hypoeutectic was better. In the porous network structure of Si O2 nanofibers, the dispersion is attributed to the capillary effect and surface tension between fatty acids and Si O2. At the same time, the composite phase change materials have suitable phase transition temperature and higher enthalpy, and the electrospun Si O2 nanofibers improve the thermal energy storage/release rate of the composite phase change materials. TiO_2-doped SiO_2 (TiO_2/SiO_2) nanofibers were prepared by electrospinning and high temperature calcination with n-butyl titanate (TBT) and tetraethyl orthosilicate (TEOS) as precursors. The composition, crystal structure and morphology of TiO_2/SiO_2 nanofibers prepared at three calcination temperatures (600oC, 900oC and 1200oC) were characterized by FT-IR, XRD and SEM. The results show that the amorphous structure of TiO_2/SiO_2 nanofibers changes from 600oC to 1200oC with the increase of calcination temperature, and the morphology of the nanofibers changes from uniform and smooth cylinder at 600oC to calcification at 1200oC. In addition, the TiO_2/SiO_2-based composites are prepared by SEM, adsorption properties and DSC at different heat treatment temperatures. The morphology, adsorption capacity and thermal properties of the phase change materials were compared. The results showed that the low-eutectic binary fatty acids were dispersed uniformly in the porous network structure of TiO_2/SiO_2 nanofibers. With the increase of calcination temperature, the morphology of TiO_2/Si_2 nanofibers changed, resulting in low-eutectic binary fatty acids. The decrease of the adsorption capacity of the melt leads to the decrease of the thermal storage property of the composite shape stabilized phase change material.
【學(xué)位授予單位】：江南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB34;TQ340.64
本文編號(hào)：2208470
[Abstract]:The rational use of energy and the development of new energy sources have always been the focus of attention. In order to alleviate the contradiction between energy shortage, rapid growth of energy consumption and environmental pollution, the use of latent heat of phase change materials for energy storage and release is a new environmental protection and energy-saving technology, which can be used to control the temperature of the system or environment. Fatty acids are a kind of important solid-liquid phase change materials, which have the advantages of high heat storage density and constant temperature during phase change process. However, they have the disadvantages of large phase change volume change and low thermal conductivity. However, electrospun inorganic nanofibers have high specific surface area and unique network junction. Structures, abundant porosity and high thermal conductivity can be used as support materials for solid-liquid phase change materials, which can effectively solve the leakage and low thermal conductivity problems in fatty acid phase change process. CA binary fatty acid eutectics (CA-LA, CA-MA, CA-PA and CA-SA) and CA-LA-PA ternary fatty acid eutectics were prepared by melt mixing and ultrasonic dispersion using decanoic acid (CA), lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA) as raw materials and used as phase change materials. SiO_2 nanofibers and TiO_2-doped SiO_2 (TiO_2/SiO_2) nanofibers were prepared by calcination and used as supporting materials. Then the composite phase change materials were prepared by the method of physical adsorption of fatty acids on nanofibers. The morphology and properties of the composite phase change materials were studied. The PVP/Si O2 composite nanofibers were prepared. The thermal degradation process was studied by TGA. Then the Si O2 nanofibers were prepared by calcination at 500oC, 600oC and 700oC. The composition and functional groups of the nanofibers were characterized by FT-IR. The formation of Si O2 nanofibers at different calcination temperatures was compared and analyzed. The adsorption properties of nanofibers for methylene blue dye and CA-LA-PA ternary fatty acid hypoeutectic were studied. The results showed that the porous network Si O2 nanofibers prepared by calcination at 600oC had higher adsorption capacity. 2. The structure and morphology of Si O2 nanofibers were further characterized by XRD and SEM. The results showed that Si O2 nanofibers had good adsorption properties. The morphology, adsorption capacity, thermal storage and thermal energy storage/release properties of SiO2-based composite phase change materials were studied by means of SEM, adsorption properties, DSC and self-assembled thermal performance tester. The results showed that the binary fatty acid hypoeutectic was better. In the porous network structure of Si O2 nanofibers, the dispersion is attributed to the capillary effect and surface tension between fatty acids and Si O2. At the same time, the composite phase change materials have suitable phase transition temperature and higher enthalpy, and the electrospun Si O2 nanofibers improve the thermal energy storage/release rate of the composite phase change materials. TiO_2-doped SiO_2 (TiO_2/SiO_2) nanofibers were prepared by electrospinning and high temperature calcination with n-butyl titanate (TBT) and tetraethyl orthosilicate (TEOS) as precursors. The composition, crystal structure and morphology of TiO_2/SiO_2 nanofibers prepared at three calcination temperatures (600oC, 900oC and 1200oC) were characterized by FT-IR, XRD and SEM. The results show that the amorphous structure of TiO_2/SiO_2 nanofibers changes from 600oC to 1200oC with the increase of calcination temperature, and the morphology of the nanofibers changes from uniform and smooth cylinder at 600oC to calcification at 1200oC. In addition, the TiO_2/SiO_2-based composites are prepared by SEM, adsorption properties and DSC at different heat treatment temperatures. The morphology, adsorption capacity and thermal properties of the phase change materials were compared. The results showed that the low-eutectic binary fatty acids were dispersed uniformly in the porous network structure of TiO_2/SiO_2 nanofibers. With the increase of calcination temperature, the morphology of TiO_2/Si_2 nanofibers changed, resulting in low-eutectic binary fatty acids. The decrease of the adsorption capacity of the melt leads to the decrease of the thermal storage property of the composite shape stabilized phase change material.
【學(xué)位授予單位】：江南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB34;TQ340.64
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