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磁性微膠囊相變材料及聚酰亞胺復(fù)合薄膜的合成與表征

發(fā)布時(shí)間:2019-02-23 17:15
【摘要】:相變材料(PCMs)在相變的過程中能夠從環(huán)境中吸收或釋放熱量,起到儲(chǔ)存能量和管理溫度的作用。而常用的PCMs在相變的過程中會(huì)發(fā)生固態(tài)和液態(tài)的轉(zhuǎn)變導(dǎo)致泄漏的發(fā)生,因此需要將PCMs進(jìn)行封裝。本文采用微膠囊封裝技術(shù)對(duì)PCMs進(jìn)行封裝。第二章中設(shè)計(jì)了一種兼具儲(chǔ)熱功能和磁性功能的雙功能微膠囊相變材料(MEPCMs),該MEPCMs以正二十烷為芯材,四氧化三鐵/二氧化硅(Fe3O4/SiO2)復(fù)合材料為壁材。制備的過程中首先采用Pickering乳液的方法將Fe304納米粒子(Fe3O4 NPs)自組裝到正二十烷液滴的表面,然后引發(fā)正硅酸四乙酯(TEOS)在油-水界面處的水解和縮聚反應(yīng)形成致密的Si02保護(hù)層。制得的磁性MEPCMs具有以下特性:(1)表現(xiàn)為完美的球狀形貌且具有核一殼結(jié)構(gòu);(2)由表面至中心的化學(xué)成分分別是Si02、Fe304和正二十烷;(3)壁材中的Fe3O4 NPs具有反尖晶石結(jié)構(gòu),而Si02是無定型的;(4)具有超順磁性;(5)具有良好的相變性能、熱穩(wěn)定性和耐用性。該磁性MEPCMs具有的雙功能特性使得其可應(yīng)用于調(diào)溫和防輻射纖維或織物,紅外和電磁屏蔽產(chǎn)品或電子芯片的抗干擾涂層等領(lǐng)域。第三章設(shè)計(jì)了一種兼具溫度管理功能和電磁屏蔽功能的聚酰亞胺(PI)復(fù)合薄膜。PI復(fù)合薄膜的制備采用兩步法,首先合成有機(jī)硅包覆的磁性MEPCMs,然后將制得的磁性MEPCMs與PI復(fù)合。合成有機(jī)硅包覆的磁性MEPCMs的過程中首先以聚乙二醇(PEG)為分散相,液體石蠟為連續(xù)相,制得油包水的乳液,然后引發(fā)甲基三甲氧基硅烷(MTMS)在水-油界面處的水解和縮聚反應(yīng)生成有機(jī)硅的外殼。而制備PI復(fù)合薄膜的過程中,首先制備PAA和磁性MEPCMs的粘稠的混合液體,然后將PAA和磁性微膠囊的混合液體流延成膜,在高溫下熱環(huán)化制得PI復(fù)合薄膜。磁性MEPCMs和PI復(fù)合薄膜具有以下特征:(1)磁性MEPCMs呈現(xiàn)碗形結(jié)構(gòu),具有完美的核-殼結(jié)構(gòu),而PI復(fù)合薄膜中的磁性微膠囊分布在PI的基體中并被PI基體包圍起來;(2)磁性MEPCMs的芯材是PEG/Fe3O4復(fù)合材料,壁材是有機(jī)硅;(3)磁性MEPCMs具有良好的相變性能和熱穩(wěn)定性,而PI復(fù)合薄膜的熱穩(wěn)定性雖然出現(xiàn)了一定程度的下降,但是仍具有優(yōu)異的熱穩(wěn)定性;(4)制得的PI復(fù)合薄膜具有優(yōu)異的電磁屏蔽效能。綜上所述,制得的PI復(fù)合薄膜不僅能夠起到管理溫度的作用,還能夠作為電磁屏蔽材料,可廣泛的應(yīng)用于電子設(shè)備及其元件的生產(chǎn)與制備。
[Abstract]:Phase change material (PCMs) can absorb or release heat from the environment in the process of phase transition, which plays the role of energy storage and temperature management. However, the transition of solid and liquid state will occur in the process of phase transition of PCMs, so it is necessary to encapsulate PCMs. In this paper, microencapsulation technology is used to encapsulate PCMs. In chapter 2, a dual-function microencapsulated phase change material (MEPCMs),) with both heat storage and magnetic properties was designed. The core material of MEPCMs was n-eicosane, and the Fe _ 2O _ 3 / Fe3O4/SiO2 composite was used as wall material. In the process of preparation, Fe304 nanoparticles (Fe3O4 NPs) were self-assembled onto the surface of n-eicosane droplets by the method of Pickering emulsion. Then the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) at the oil-water interface were initiated to form a dense Si02 protective layer. The obtained magnetic MEPCMs has the following characteristics: (1) perfect spherical morphology and core-shell structure; (2) the chemical composition from the surface to the center is Si02,Fe304 and n-eicosane, respectively. (3) Fe3O4 NPs in the wall has antispinel structure, while Si02 is amorphous, (4) superparamagnetic, (5) good phase change, thermal stability and durability. The dual functional properties of the magnetic MEPCMs allow it to be used in the fields of thermostat and radiation resistant fibers or fabrics, infrared and electromagnetic shielding products, or anti-interference coatings for electronic chips. In chapter 3, a polyimide (PI) composite film with both temperature management and electromagnetic shielding function was designed. The preparation of PI composite film was carried out by two-step method. Firstly, the silicone coated magnetic MEPCMs, was synthesized. Then the magnetic MEPCMs and PI were synthesized. In the process of synthesizing silicon-coated magnetic MEPCMs, water in oil emulsion was prepared by using polyethylene glycol (PEG) as dispersion phase and liquid paraffin as continuous phase. Then the hydrolysis and Polycondensation of methyl trimethoxysilane (MTMS) at the water-oil interface to form an organic silicon shell were initiated. In the process of preparing PI composite film, the viscous mixed liquid of PAA and magnetic MEPCMs was first prepared, and then the mixed liquid of PAA and magnetic microcapsule was formed into film, and the PI composite film was prepared by thermal cyclization at high temperature. The magnetic MEPCMs and PI composite films have the following characteristics: (1) the magnetic MEPCMs has a perfect core-shell structure, and the magnetic microcapsules in the PI composite film are distributed in the PI substrate and surrounded by the PI substrate; (2) the core material of magnetic MEPCMs is PEG/Fe3O4 composite material, and the wall material is organosilicon; (3) the magnetic MEPCMs has good phase transformation and thermal stability, while the thermal stability of PI composite film decreases to some extent, but it still has excellent thermal stability. (4) the PI composite film has excellent electromagnetic shielding efficiency. In conclusion, the prepared PI composite film can not only play the role of temperature management, but also can be used as electromagnetic shielding material, can be widely used in the production and preparation of electronic equipment and its components.
【學(xué)位授予單位】:北京化工大學(xué)
【學(xué)位級(jí)別】:碩士
【學(xué)位授予年份】:2015
【分類號(hào)】:TB34;TB383.2

【共引文獻(xiàn)】

相關(guān)期刊論文 前4條

1 閻若思;王瑞;劉星;;相變材料微膠囊在蓄熱調(diào)溫智能紡織品中的應(yīng)用[J];紡織學(xué)報(bào);2014年09期

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相關(guān)博士學(xué)位論文 前2條

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相關(guān)碩士學(xué)位論文 前8條

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