采用原位聚合法合成了一种以正十八烷为芯材,密胺树脂为壁材的相变纳米级胶囊;通过超声搅拌将相变纳胶囊和功能化的多壁碳纳米管复合,得到一种稳定的复合相变流体,并通过红外光谱(FT-IR)、扫描电镜(SEM)、Zeta电位和差示量热(DSC)等手段对其进行表征。结果表明:Fenton试剂处理过的多壁碳纳米管表面带有大量的—OH和—COOH等亲水性基团;合成的正十八烷相变纳胶囊为直径200～400nm的表面光滑的圆球形;Zeta电位测试结果显示,当表面活性剂曲拉通X-100和十六烷基三甲基溴化铵(CTAB)的用量都为3.3%时,复合相变流体的分散稳定性最好;DSC结果显示,复合相变流体使用前、后烘干物的熔融焓和结晶焓都在110J/g左右。
A phase change nano-capsule with n-octadecane as core material and melamine resin as wall material was synthesized by in-situ polymerization.Then,the phase-change nano-capsule and the multi-walled nanotubes(MWCNTS) functionalized were stirred together by ultrasonic method to obtain a stable composite phase-change fluid which was characterized through FT-IR,SEM,Zeta potential and DSC.The results shown that MWCNTS treated by Fenton reagent had some hydrophilic groups such as a large amount of —OH and —COOH on the surface.The n-octadecane phase-chage nano-capluse formed smooth sphere whose diameter were between 200～400nm.Zata potential test results illustrated that when the amount of surfactant Triton X-1000 and CTAB were both 3.3%,the composite phase-change fluid had the optimal dispersion stability.In addition,through the DSC results,the melting enthalpy and crystallization enthalpy of the dried composite phase-change fluid were both keeping 110J/g during the using period.
[1] Medina M A,King J B,Zhang M.On the heat transfer rate reduction of structural insulated panels (SIPs) outfitted with phase change materials (PCMs)[J].Energy,2008,33(4):667-678.
[2] Huang L,Petermann M,Doetsch C.Evaluation of paraffin/water emulsion as a phase change slurry for cooling applications[J].Energy,2009,34(9):1145-1155.
[3] Wen X,Shao L,Xue Y,et al.A rapid learning algorithm for vehicle classification[J].Information Sciences,2015,295:395-406.
[4] Xia L,Zhang P,Wang R Z.Numerical heat transfer analysis of the packed bed latent heat storage system based on an effective packed bed model[J].Energy,2010,35(5):2022-2032.
[5] Yang Y Y,Wang H,Song G L,et al.Dual-functional phase change nanocapsules based on n-octadecane core and polypyrrole shell[J].Key Engineering Materials,2016,697:781-784.
[6] Cui R,Liu X,Yu W,et al.Preparation and characterization of microencapsulated n-octadecane as phase change materials[J].Journal of Fiber Bioengineering & Informatics,2012,5(1):372-375.
[7] Chen L,Wang T,Zhao Y,et al.Characterization of thermal and hydrodynamic properties for microencapsulated phase change slurry (MPCS)[J].Energy Conversion & Management,2014,79:317-333.
[8] Wang X,Niu J,Li Y,et al.Flow and heat transfer behaviors of phase change material slurries in a horizontal circular tube[J].International Journal of Heat & Mass Transfer,2007,50(13-14):2480-2491.
[9] Rao Y,Lin G,Luo Y,et al.Preparation and thermal properties of microencapsulated phase change material for enhancing fluid flow heat transfer[J].Heat Transfer-Asian Research,2007,36(1):28-37.
[10] Wu S,Zhu D,Zhang X,et al.Preparation and melting/freezing characteristics of Cu/paraffin nanofluid as phase-change material (PCM)[J].Energy & Fuels,2010,24(3):1894-1898.
[11] Le H H,Wieβner S,Das A,et al.Selective wetting of carbon nanotubes in rubber compounds-effect of the ionic liquid as dispersing and coupling agent[J].European Polymer Journal,2016,75:13-24.
[12] Song X J,Wang L,Tang C Y,et al.Fabrication of carbon nanotubes incorporated double-skinned thin film nanocomposite membranes for enhanced separation performance and antifouling capability in forward osmosis process[J].Desalination,2015,369:1-9.
[13] Avilés F,Cauich-Rodríguez J V,Moo-Tah L,et al.Evaluation of mild acid oxidation treatments for MWCNT functionalization[J].Carbon,2009,47(13):2970-2975.
[14] Yamagishi Y,Sugeno T,Ishige T,et al.An evaluation of microencapsulated PCM for use in cold energy transportation medium[C].United States:Intersociety Energy Conversion Engineering Conference,1996.
[15] Laura Fedele,Laura Colla,Sergio Bobbo,et al.Experimental stability analysis of different water-based nanofluids[J].Nanoscale Research Letters,2011,6(1):300-307.
[16] 陈立飞,吴峰,张晖,等.碳纳米管表面羟基化及其纳米流体的导热性能研究[J].上海第二工业大学学报,2009,26(2):94-98.
[17] Li M,Chen M,Wu Z.Enhancement in thermal property and mechanical property of phase change microcapsule with modified carbon nanotube[J].Applied Energy,2014,127:166-171.
[18] 吴炳洋,郑帼,孙玉,等.石墨烯/正十八烷微胶囊的制备与及其热性能研究[J].高分子学报,2016(2):242-249.
[19] Yuan P,Zhang P,Liang T,et al.Effects of functionalization on energy storage properties and thermal conductivity of graphene/n-octadecane composite phase change materials[J].Journal of Materials Science,2019,54(2):1488-1501.
