膨胀石墨/石蜡复合相变材料的电阻率分析
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摘要
采用熔融共混法制备石蜡/膨胀石墨复合相变材料,使用半导体粉末电阻率测试仪对天然鳞片石墨、提纯石墨、可膨胀石墨、石蜡/膨胀石墨复合相变材料在不同压强下的电阻率进行测试。发现所有材料的电阻率都随压强的增加而减小,对导热性能最好的相变材料进行7次重复测试,材料电阻率在0.210~0.535?·cm之间变化,依然小于1?·cm,属于低电阻率材料。根据测试数据计算不同压强情况下相变材料单位体积蓄热量、密度、体积和电阻值。材料的单位体积蓄热量和密度随压强增大而增大,体积和电阻则相反,压强在4~10MPa之间时物理性能比较稳定,在10MPa左右时,相变材料电阻值比天然鳞片石墨最大增大884倍、体积1.9倍、密度0.6倍,单位体积蓄热量同比4 MPa时最大增加22.8%,压缩之后单位体积蓄热量提高。说明膨胀石墨/石蜡复合材料属于低电阻率相变材料,应用于沥青路面,能够实现升温和降温的双重效果。
Expandable graphite-paraffin composite phase change materials were prepared by a melt-blending process. The resistivity of natural flake graphite, purified graphite, expandable graphite,paraffin-expanded graphite composite phase change materials formed at different pressures was measured using a semiconductor powder resistivity tester. The results showed that the resistivity of all materials decreased with increasing pressure, seven repeated tests were performed on the material with the best thermal conductivity, and the resistivity of the material varied between 0.210—0.535 ?·cm,which was lower than 11 ?·cm and hence can be classified as a low-resistivity material. According to the measurement data, the amount of heat storage per unit volume, density, volume and resistance of the composite phase change materials were calculated. The amount of heat storage per unit volume and density of the material increased with increasing pressure, however, the resistivity and volume showed the opposite as expected. The physical properties of materials were found to be stable when the formation pressure was between 4 and 10 MPa; at about 10 MPa, the resistivity of the phase change material was 884 times larger than that of natural scale graphite, 1.9 times the volume and 0.6 times thedensity. The amount of heat storage per unit volume was 22.8% higher than that at 4 MPa. It was shown that the expanded graphite/paraffin composite was a low resistivity phase transition material, which can be applied on asphalt pavement, achieving both heating up and cooling down effects.
Expandable graphite-paraffin composite phase change materials were prepared by a melt-blending process. The resistivity of natural flake graphite, purified graphite, expandable graphite,paraffin-expanded graphite composite phase change materials formed at different pressures was measured using a semiconductor powder resistivity tester. The results showed that the resistivity of all materials decreased with increasing pressure, seven repeated tests were performed on the material with the best thermal conductivity, and the resistivity of the material varied between 0.210—0.535 ?·cm,which was lower than 11 ?·cm and hence can be classified as a low-resistivity material. According to the measurement data, the amount of heat storage per unit volume, density, volume and resistance of the composite phase change materials were calculated. The amount of heat storage per unit volume and density of the material increased with increasing pressure, however, the resistivity and volume showed the opposite as expected. The physical properties of materials were found to be stable when the formation pressure was between 4 and 10 MPa; at about 10 MPa, the resistivity of the phase change material was 884 times larger than that of natural scale graphite, 1.9 times the volume and 0.6 times thedensity. The amount of heat storage per unit volume was 22.8% higher than that at 4 MPa. It was shown that the expanded graphite/paraffin composite was a low resistivity phase transition material, which can be applied on asphalt pavement, achieving both heating up and cooling down effects.
引文
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[15]李玉峰,赖奇,魏亚林,等.红鳞片石墨的提纯研究[J].化学工程师, 2007, 142(7):51-53.LIYufeng,LAIQi,WEIYalin,etal.Purificationoffinescalegraphite[J]. Chemical Engineer, 2007, 142(7):51-53.
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[18]梅辰,田金星.细粒高倍率膨胀石墨的制备[J].非金属矿,2011,34(5):30-32.Mei Chen, Tian Jinxing. Preparation of the highly expanded graphiteusing fine flaky graphite[J]. Non-Metallic Mines, 2011, 34(5):30-32.
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[20]徐众,万书权,邓建梅,等.石蜡/不同粒径膨胀石墨复合相变材料的制备及性能研究[J].化工新型材料, 2017, 45(5):57-60.XUZhong,WANShuquan,DENGJianmei,etal.Preparationandperformancestudyonphasechangematerialcompositeofparaffin/different particle sized expanded graphite[J]. New ChemicalMaterials, 2017, 45(5):57-60.
[21]施钰川.太阳能原理与技术[M].西安:西安交通大学出版社,2009:69-70.SHI Yuchuan. Principles and technologies of solar energy[M]. Xi’an:Xi’an Jiaotong University Press, 2009:69-70.
[22]王青青,范鹏远,陈玉明,等.膨胀石墨/石蜡复合相变材料热-电特性实验研究[J].塑料工业, 2018, 46(9):129-133+137.WANGQingqing,FANPengyuan,CHENYuming,etal.Experimentalstudyonthethermo-physicalandelectricalpropertiesofparaffin/expandedgraphitecompositephasechangematerials[J].China Plastics Industry, 2018, 46(9):129-133+137.
[2]HARIHARAN K, KUMAR G S, KUMARESAN G. Investigation onphasechangebehaviorofparaffinphasechangematerialinasphericalcapsuleforsolarthermalstorageunits[J].HeatTransferEngineering, 2017, 136(1):775-783.
[3]孙文鸽,韩磊,吴志根.膨胀石墨/石蜡相变复合材料有效导热系数的数值计算[J].复合材料学报, 2015, 32(6):1596-1601.SUN wenge, HAN Lei, WU Zhigen. Numerial calculation of effectivethermal conductivity coefficients of erpanded graphite/paraffin phasechange composites[J]. Acta Materiae Compositae Sinica, 2015, 32(6):1596-1601.
[4]李云涛,晏华,王群,等.膨胀石墨对石蜡膨胀石墨复合相变材料热工性能的影响[J].化工新型材料, 2017, 45(5):215-217.LIYuntao,YANHua,WANGQun,etal.Influenceofexpandedgraphite on thermal property of paraffin[J]. New Chemical Materials,2017, 45(5):215-217.
[5]IGORK,PATRIKS,HANEENA,etal.Naturalagingofshapestabilized phase change materials based on paraffin wax[J]. PolymerTesting, 2017, 63:567-572.
[6]张显勇,王忠,付蕾,等.有机复合相变储能材料的强化传热研究[J].陕西理工学院学报(自然科学版), 2017, 33(1):6-10.ZHANGXianyong,WANGZhong,FULei,etal.Studyonintensifyingthethermalconductivityoforganiccompositephasechange energy storage materials[J]. Journal of Shaanxi University ofTechnology(Natural Science Edition), 2017, 33(1):6-10.
[7]张显勇,王忠,付蕾,等.支撑材料对中低温有机相变储能材料储热性能的影响研究[J].化工新型材料, 2017, 45(5):54-56.ZHANGXianyong,WANGZhong,FuLei,etal.Studyontheinfluence of supporting material on the thermal storage propertyofmiddle and low temperature organic phase change storage material[J].New Chemical Materials, 2017, 45(5):54-56.
[8]史巍,程素香.石蜡石墨粉复合相变材料在温室大棚中的控温效果研究[J].硅酸盐通报, 2017, 36(12):4112-4116.SHIWei,CHENGSuxiang.TemperatureControlEffectofParaffinGraphiteCompositePhaseChangeMaterialsinGreenhouse[J].Bulletin of the Chinese Ceramic Societ, 2017, 36(12):4112-4116.
[9]杜嘉雯,李勋峰.石蜡/膨胀石墨复合相变保温砂浆的制备及性能研究[J].建筑与文化, 2015, 11(12):135-137.DUJiawen,LIXunfeng.Preparationandperformancestudyofparaffins/expandedgraphitecompositephasechangematerial[J].Architecture&Culture, 2015, 11(12):135-137.
[10]李云涛,晏华,汪宏涛,等.石蜡/膨胀石墨复合相变材料对磷酸镁水泥水化性能的影响[J].硅酸盐通报, 2016, 35(9):3007-3013.LIYuntao,YANHua,WANGHongtao,etal.Effectofparaffin/expandedgraphitecomposite phasechangematerials onthehydration performances of magnesium phosphate cement[J]. Bulletinof the Chinese Ceramic Society, 2016, 35(9):3007-3013.
[11]何丽红,杨帆,佟禹,等.石蜡/膨胀石墨复合相变材料在冷拌沥青混合料中的应用[J].公路, 2016, 61(8):181-185.HELihong,YANGFan,TONGYu,etal.Applicationofphasechange fine aggregate in cold mix asphalt mixture[J]. Highway, 2016,61(8):181-185.
[12]高学农,李得伦,孙滔,等.石蜡/膨胀石墨复合相变材料控温电子散热器的性能[J].华南理工大学学报(自然科学版), 2012, 40(1):7-12.GAOXuenong,LIDelun,SUNTao,etal.Performanceoftemperature-controlledelectronicheatsinkwithcompositeparaffin/expandedgraphitephasechangematerial[J].JournalofSouthChinaUniversityofTechnology(NaturalScienceEdition),2012, 40(1):7-12.
[13]于华洋.低电阻率沥青路面材料的制备及导电机理研究[D].南京:东南大学, 2013.YU Huayang. Thestudy on fabrication and conductivitymechanismof low-electrical-resistivity mixture applied on asphalt pavement[D].Nanjing:Southeast University, 2013.
[14]王昊鹏.自修复型导电沥青混凝土设计与评价[D].南京:东南大学, 2016.WANGHaopeng.Designandevaluationofconductiveasphaltconcrete for self-healing[D]. Nanjing:Southeast University, 2016.
[15]李玉峰,赖奇,魏亚林,等.红鳞片石墨的提纯研究[J].化学工程师, 2007, 142(7):51-53.LIYufeng,LAIQi,WEIYalin,etal.Purificationoffinescalegraphite[J]. Chemical Engineer, 2007, 142(7):51-53.
[16]赵国刚,马吉阳,吴岩.双氧水氧化法制备可膨胀石墨[J].黑龙江科技学院学报, 2014, 24(2):173-176.ZHAOGuogang,MAJiyang,WUYan.Preparationofexpandablegraphite using H2O2 as oxidation[J]. Journal of Heilongjiang Instituteof Science and Technology, 2014, 24(2):173-176.
[17]涂文懋,邹琴,潘群,等.无硫高膨胀倍数可膨胀石墨的制备研究[J].武汉理工大学学报, 2012, 34(4):72-75.TUWenmao,ZOUQin,PANQun,etal.Preparationofhighexpansion ratio sulfur-free expandable graphite[J]. Journal of WuhanUniversity of Technology, 2012, 34(4):72-75.
[18]梅辰,田金星.细粒高倍率膨胀石墨的制备[J].非金属矿,2011,34(5):30-32.Mei Chen, Tian Jinxing. Preparation of the highly expanded graphiteusing fine flaky graphite[J]. Non-Metallic Mines, 2011, 34(5):30-32.
[19]徐众,万书权,韩洪波,等.天然鳞片石墨制备可膨胀石墨的工艺研究[J].无机盐工业, 2016, 48(5):30-34.XU Zhong, WAN Shuquan, HAN Hongbo, et al. Study on preparationofexpandablegraphitefromnaturalflakegraphite[J].InorganicChemicals Industry, 2016, 48(5):30-34.
[20]徐众,万书权,邓建梅,等.石蜡/不同粒径膨胀石墨复合相变材料的制备及性能研究[J].化工新型材料, 2017, 45(5):57-60.XUZhong,WANShuquan,DENGJianmei,etal.Preparationandperformancestudyonphasechangematerialcompositeofparaffin/different particle sized expanded graphite[J]. New ChemicalMaterials, 2017, 45(5):57-60.
[21]施钰川.太阳能原理与技术[M].西安:西安交通大学出版社,2009:69-70.SHI Yuchuan. Principles and technologies of solar energy[M]. Xi’an:Xi’an Jiaotong University Press, 2009:69-70.
[22]王青青,范鹏远,陈玉明,等.膨胀石墨/石蜡复合相变材料热-电特性实验研究[J].塑料工业, 2018, 46(9):129-133+137.WANGQingqing,FANPengyuan,CHENYuming,etal.Experimentalstudyonthethermo-physicalandelectricalpropertiesofparaffin/expandedgraphitecompositephasechangematerials[J].China Plastics Industry, 2018, 46(9):129-133+137.