本文選題：改性碳納米管　切入點(diǎn)：相變微膠囊　出處：《東南大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著工業(yè)化、城鎮(zhèn)化、現(xiàn)代化的推進(jìn),我們對(duì)能源的需求越來(lái)越大,要求也越來(lái)越高,可是能源的儲(chǔ)量日趨減少,利用率低,供給矛盾大,對(duì)環(huán)境污染嚴(yán)重,這些問題都給可持續(xù)發(fā)展帶來(lái)了一定的影響,而相變儲(chǔ)能技術(shù)作為一種新型技術(shù)手段,可以解決能量供求在時(shí)間和空間上不匹配的矛盾問題,有效提高能源利用率。石蠟作為相變材料的一種,存在著易泄露和導(dǎo)熱低的缺點(diǎn),為解決該問題,本課題采用綠色環(huán)保、穩(wěn)定性、成膜性、封裝效果好的甲基丙烯酸甲酯為壁材,采用3種不同乳化體系：Tween-80體系、SDBS/Span-80、Tween-80/Span-80,通過(guò)微膠囊化技術(shù)對(duì)石蠟進(jìn)行封裝,結(jié)果表明：采用Tween-80/Span-80乳化體系熱焓值為91.76J/g,導(dǎo)熱系數(shù)為01226 W/(m-k),微膠囊分散性好,粒徑小且均勻,致密無(wú)自聚體粘附,并且有著規(guī)則的球形形貌。甲基丙烯酸甲酯的包覆可明顯降低芯材的泄露率,但同時(shí)也存在著導(dǎo)熱性能差、強(qiáng)度低、熱穩(wěn)定性差、易老化等缺點(diǎn);無(wú)機(jī)壁材的導(dǎo)熱優(yōu)于有機(jī)壁材,其熱穩(wěn)定性、機(jī)械強(qiáng)度、化學(xué)穩(wěn)定性等方面較有機(jī)壁材出色許多,為了進(jìn)一步提高微膠囊的導(dǎo)熱性能,本課題采用無(wú)機(jī)壁材SiO2進(jìn)行二次包覆,結(jié)果表明：二次包覆制備的相變微膠囊球形形貌好,表面光滑致密,分散性好,粒度均勻,熱焓為72.51J/g,導(dǎo)熱系數(shù)較高,達(dá)到0.1724W/(m k),相比聚甲基丙烯酸甲酯/石蠟相變微膠囊的導(dǎo)熱提高了40.62%。為了進(jìn)一步提高相變微膠囊的導(dǎo)熱性能,本課題采用改性碳納米管作為導(dǎo)熱添加劑,結(jié)果表明：PMMA-SiO2/P-C 18/CNTs-C 18微膠囊的導(dǎo)熱系數(shù)相比石蠟,PMMA/Paraffin微膠囊,PMMA-SiO2/Paraffin微膠囊分別提高了56.25%,129.52%,63.22%,并達(dá)到0.2814 W/(m·k),加入 CNTs-COOH時(shí),導(dǎo)熱系數(shù)達(dá)到0.3024 W/(m·k)。將導(dǎo)熱性能優(yōu)異的相變微膠囊與電子控溫裝置結(jié)合,來(lái)解決電子芯片的散熱問題,結(jié)果表明：當(dāng)相變微膠囊的導(dǎo)熱值分別提高15.97%,22.09%的時(shí)候,控溫時(shí)間分別可提高40.11%,22.22%,故填充導(dǎo)熱系數(shù)高的微膠囊,可以大大提高散熱片的散熱效果,涂覆金屬漆后,由于散熱面積與導(dǎo)熱的提高,可以大大減緩溫度的上升速度：從散熱片的表面熱紅外圖可以發(fā)現(xiàn)摻入相變金屬漆的散熱片,表面溫度上升速率慢,在30min溫度處于41℃左右,比未摻入相變微膠囊的溫度低了4℃,這說(shuō)明相變微膠囊可以被應(yīng)用于電子控溫領(lǐng)域。
[Abstract]:With the development of industrialization, urbanization and modernization, our demand for energy is increasing and our requirements are getting higher and higher. However, the reserves of energy are decreasing, the utilization ratio is low, the supply is contradictory, and the pollution to the environment is serious. These problems have a certain impact on sustainable development, and phase change energy storage technology, as a new technical means, can solve the contradiction between energy supply and demand in time and space. As a kind of phase change material, paraffin has the disadvantages of easy leakage and low thermal conductivity. In order to solve this problem, this subject adopts green environmental protection, stability, film forming, Methyl methacrylate (MMA) with good encapsulation effect was used as wall material, and three different emulsifying systems: Tween-80 / SDBS / Span-80 / Tween-80 / Span-80 were used to encapsulate paraffin wax by microencapsulation technology. The results showed that the enthalpy of Tween-80/Span-80 emulsified system was 91.76J / g and the thermal conductivity was 01226 W / m ~ (-1). The microcapsules had good dispersity, small and uniform particle size, and no self-polymer adhesion. The coating of methyl methacrylate can obviously reduce the leakage rate of the core material, but it also has some disadvantages such as poor thermal conductivity, low strength, poor thermal stability, easy aging and so on. The thermal conductivity of inorganic wall material is better than that of organic wall material, and the thermal stability, mechanical strength and chemical stability of inorganic wall material are much better than that of organic wall material. In order to further improve the thermal conductivity of microcapsule, the SiO2 of inorganic wall material is used for secondary coating. The results show that the phase change microcapsules prepared by secondary coating have good spherical morphology, smooth and compact surface, good dispersion, uniform particle size, high enthalpy of 72.51J / g and high thermal conductivity. In order to further improve the thermal conductivity of phase change microcapsules, modified carbon nanotubes (CNTs) were used as heat conduction additives, compared with that of polymethyl methacrylate / paraffin phase change microcapsules (PCMs). The results showed that the thermal conductivity of the microcapsules: PMMA-SiO _ 2 / P-C _ (18) / CNTs-C _ (18) was higher than that of the paraffin PMMA / Paraffin microcapsule PMMA-SiO _ 2 / Paraffin microcapsules by 56.25% 129.52%, and reached 0.2814 W / m 路kg ~ (-1). When CNTs-COOH was added, the thermal conductivity of the microcapsules was 0.3024 W/ / m 路KG. The phase change microcapsules with excellent thermal conductivity were combined with the electronic temperature control device. The results show that when the thermal conductivity of phase change microcapsules is increased by 15.97% or 22.09%, the temperature control time can be increased by 40.11% and 22.22%, respectively. Therefore, filling microcapsules with high thermal conductivity can greatly improve the heat dissipation effect of the radiator. After coating with metal paint, the rising rate of temperature can be slowed down greatly because of the increase of heat dissipation area and heat conduction. From the surface thermal infrared diagram of the heat sink, it can be found that the heat sink mixed with phase change metal paint has a slow rising rate of surface temperature. The temperature is about 41 鈩，

本文編號(hào)：1625061