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Emerging low-density polyethylene/paraffin wax/aluminum composite as a form-stable phase change thermal interface material

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 772-781页

作者： Chuanchang Li Weixuan Wang Xiaoliang Zeng Chunxuan Liu Rong Sun School of Energy and Power Engineering Changsha University of Science and TechnologyChangsha 410114China Shenzhen Institute of Advanced Electronic Materials Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Hunan Xiangtou Light Material Technology Co. Ltd.Changsha 410012China

Thermal interface materials(TIMs) play a vital role in the thermal management of electronic devices and can significantly reduce thermal contact resistance(TCR). The TCR between the solid–liquid contact surface is much smaller than that of the solid–solid contact surface, but conventional solid–liquid phase change materials are likely to cause serious leakage. Therefore, this work has prepared a new formstable phase change thermal interface material. Through the melt blending of paraffin wax(PW) and low-density polyethylene(LDPE), the stability is improved and it has an excellent coating effect on PW. The addition of aluminum(Al) powder improves the low thermal conductivity of PW/LDPE, and the addition of 15wt% Al powder improves the thermal conductivity of the internal structure of the matrix by 67%. In addition, the influence of the addition of Al powder on the internal structure, thermal properties, and phase change behavior of the PW/LDPE matrix was systematically studied. The results confirmed that the addition of Al powder improved the thermal conductivity of the material without a significant impact on other properties, and the thermal conductivity increased with the increase of Al addition. Therefore, morphologically stable PW/LDPE/Al is an important development direction for TIMs.

关键词： paraffin wax low-density polyethylene phase change materials thermal interface materials form stability

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Molten solvent extraction behavior of trivalent La, Sm, Dy, and Yb with tri-n-butyl phosphate into molten paraffin wax at 60 ℃

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Rare Metals 2002年第1期21卷 7-11页

作者： PENG Bo, GAO Jinzhang, FAN Haiyan, KANG Jingwan, and YANG Wu Department of Chemistry, Northwest Normal University, Lanzhou 730070, China Department of Chemistry Northwest Normal University Lanzhou 730070

The extraction behavior of La^3+, Sm^3+, Dy^3+, and Yb^3+ insodium acetate-acetic acid medium was studied with tri-N-butylphosphate (TBP) at 60 deg. C using paraffin wax as a diluent. Theextraction percentage is greater than 85/100 in the pH range of 6 to8. The result of slope analysis method indicates that thecompositions of the extracted species are different between the lightand heavy rare ear this. The formula of the extracted species isfound to be La (TBP) (OH) (Ac)_2 for La^3+ and Yb (TBP) (OH)_3 forYb^3+. The effects of extracting time, the concentration of TBP inthe organic phase and salts on the extraction efficiency were alsodiscussed.

关键词： solvent extraction rare earth TBP paraffin wax

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Characterization and manufacturing of a paraffin wax as fuel for hybrid rockets

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Propulsion and Power Research 2018年第3期7卷 218-230页

作者： F.Piscitelli G.Saccone A.Gianvito G.Cosentino L.Mazzola CIRA Italian Aerospace Research CentreCapuaCE 81043Italy

The hybrid propulsion performed with paraffin waxes exhibits most attractive capabilities compared to solid or liquid engines,e.g.,throttleability and re-ignition,alongside higher regression rates compared to the conventional hydroxyl terminated polybutadiene(HTPB)hybrid fuel.This is because the paraffin wax forms a thin and hydro-dynamically unstable liquid layer,and then enhances the regression rate with the entrainment of droplets from the liquid-gas interface.Nevertheless,some critical open points on the manufacturing of the paraffin fuel grains still persist,because the paraffin wax exhibits high shrinkage during the solidification phase,leading to the formation of cavities,cracks and internal rips,which may be detrimental to the mechanical properties and the structural integrity of the fuel grain.In this context,this paper deals with a wide calorimetric,thermo-mechanical and physical characterization of the paraffin wax selected to manufacture the hybrid rocket engines(HRE)fuel grain,in order to gain a thorough knowledge of the material necessary to avoid the formation of critical defects.Several manufacturing methods were investigated,and it was found that only laboratory scale processes,based on the use of a heated circular mould-piston apparatus,are able to avoid the formation of critical defects,with the application of both high temperature and pressure.

关键词： paraffin wax Hybrid rockets Manufacturing SASOLs 0907 Regression rate

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Direct incorporation of paraffin wax as phase change material into mass concrete for temperature control: mechanical and thermal properties

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Research in Cold and Arid Regions 2021年第1期13卷 30-42页

作者： Tao Luo JuanJuan Ma Fang Liu MingYi Zhang ChaoWei Sun YanJun Ji XiaoSa Yuan Shaanxi Key Laboratory of Safety and Durability of Concrete Structures Xijing UniversityXi'anShaanxi 710123China State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China

Taking advantage of heat absorbing and releasing capability of phase change material(PCM),paraffin wax-based concrete was prepared to assess its automatic temperature control performance.The mechanical properties of PCM concrete with eight different paraffin wax contents were tested by the cube compression test and four-point bending test.The more paraffin wax incorporated,the greater loss of the compressive strength and bending strength.Based on the mechanical results,four contents of paraffin wax were chosen for studying PCM concrete's thermal properties,including thermal conductivity,thermal diffusivity,specific heat capacity,thermal expansion coefficient and adiabatic temperature rise.When the paraffin wax content increases from 10%to 20%,the thermal conductivity and the thermal diffusivity decrease from 7.31 kJ/(m·h·°C)to 7.10 kJ/(m·h·°C)and from 3.03×10−3 m2/h to 2.44×10−3 m2/h,respectively.Meanwhile the specific heat capacity and thermal expansion coefficient rise from 5.38×10−1 kJ/(kg·°C)to 5.76×10−1 kJ/(kg·°C)and from 9.63×10−6/°C to 14.02×10−6/°C,respectively.The adiabatic temperature rise is found to decrease with an increasing paraffin wax content.Considering both the mechanical and thermal properties,15%of paraffin wax was elected for the mass concrete model test,and the model test results confirm the effect of paraffin wax in automatic mass concrete temperature control.

关键词： phase change material paraffin wax temperature control mechanical properties thermal properties mass concrete

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Synergistic　Extraction　of　Rare　Earth　Ions　by　1-phenyl-3-methyl-4-benzoyl-5-pyrazolone　and　Trioctylphousphine　Oxide　in　paraffin　wax

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Rare Metals 1997年第1期16卷 21-27页

作者：高锦章范海燕彭波康敬万

The paraffin wax was used as an organic solvent for 1 phenyl 3 methyl 4 benzoyl 5 pyrazolone (PMBP) and trioctylphousphine oxide (TOPO) in the extraction of rare earth ions (La 3+ , Pr 3+ , Eu 3+ , Yb 3+ and Ho 3+ ) at 70℃. The composition of the extracted specices were given as RE(PMBP) 3(TOPO) 2 by means of slope analysis. The variation of the synergistic extraction equilibrium constant ( K sex ) was studied at 55℃～70℃. The thermodynamic data obtained showed that the synergistic extraction of rare earth ions by PMBP and TOPO in molten paraffin wax is exothermic and the extracted complexes were formed by TOPO bonding to the outer sphere hydration.

关键词： Synergistic extraction Rare earth paraffin wax PMBP TOPO

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Ultrafast battery heat dissipation enabled by highly ordered and interconnected hexagonal boron nitride thermal conductive composites

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Green Energy & Environment 2022年第6期7卷 1401-1410页

作者： Zhuoya Wang Kaihang Zhang Bing Zhang Zheming Tong Shulan Mao Hao Bai Yingying Lu State Key Laboratory of Chemical Engineering Institute of Pharmaceutical EngineeringCollege of Chemical and Biological EngineeringZhejiang UniversityHangzhou310027China Brook Byers Institute of Sustainable Systems and School of Civil and Environmental Engineering Georgia Institute of TechnologyAtlantaGA30332USA ZJU-Hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou311200China State Key Laboratory of Fluid Power and Mechatronic Systems College of Mechanical EngineeringZhejiang UniversityHangzhou310027China

Heat dissipation involved safety issues are crucial for industrial applications of the high-energy density battery and fast charging technology.While traditional air or liquid cooling methods suffering from space limitation and possible leakage of electricity during charge process,emerging phase change materials as solid cooling media are of growing interest.Among them,paraffin wax(PW)with large latent heat capacity and low cost is desirable for heat dissipation and thermal management which mainly hindered by their relatively low thermal conductivity and susceptibility to leakage.Here,highly ordered and interconnected hexagonal boron nitride(h-BN)networks were established via ice template method and introduced into PW to enhance the thermal conductivity.The composite with 20 wt%loading amount of h-BN can guarantee a highly ordered network and exhibited high thermal conductivity(1.86 W m^(-1) K^(-1))which was 4 times larger compared with that of random dispersed h-BN involved PW and nearly 8 times larger compared with that of bare PW.The optimal thermal conductive composites demonstrated ultrafast heat dissipation as well as leakage resistance for lithium-ion batteries(LIBs),heat generated by LIBs can be effectively transferred under the working state and the surface temperature kept 6.9℃ lower at most under 2–5℃ continuous charge-discharge process compared with that of bare one which illustrated great potential for industrial thermal management.

关键词： Hexagonal boron nitride paraffin wax Lithium-ion batteries Thermal conductive network Battery heat dissipation

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Investigation of adsorption behaviors of paraffin waxes on iron, iron oxide, and iron Ⅲ oxide pipeline's internal surfaces using adsorption locator model

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Petroleum Research 2022年第3期7卷 384-393页

作者： Ballo Mwendapole Lonje Gang Liu College of Pipelines and Civil Engineering China University of Petroleum(East China)Qingdao266580China

wax deposition in pipelines leads to pressure drop,reduced effective cross-sectional area,and blockages.Although mathematical models and experimental loops were used to model wax precipitation on pipeline surfaces,its prediction at molecular levels is not fully recognized.Molecular dynamics is another powerful approach that can predict wax precipitation at the molecular level.This paper uses molecular dynamics simulations with the adsorption locator model found in Material Studio Software to investigate the adsorption behaviors of Icosane-C20H42,Docosane-C22H46,and Tetracosane-C24H50 paraffin waxes on the Fe,FeO,and Fe2O3 pipeline internal surfaces.Modeling is performed by varying temperature values and validated with experimental data.It was found that as the temperature altered,the adsorption energies,probability energy distribution and adsorption density field on the surfaces also changed;on the other hand,the energetic analysis results showed adsorption energies increase with carbon numbers increase due to its larger surface contacting areas and lower aspect ratio,which resulted in stronger interaction with the surfaces.Further,paraffin waxes showed to adsorb easily on Fe surfaces than oxide surfaces.At temperatures below wax Appearance Temperature(WAT)on both simulations and experiments showed wax deposition.The lower adsorption energy capacity observed on the Fe2O3 pipeline surface confirms it's vitality and suitability for crude oil transportation pipelines surface lining material.

关键词： Molecular dynamics Adsorption energy Adsorption locator model Energy distribution Adsorption density field paraffin wax

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An optimized protocol using Steedman’s wax for high-sensitivity RNA in situ hybridization in shoot apical meristems and flower buds of cucumber

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Journal of Integrative Agriculture 2023年第2期22卷 464-470页

作者： WANG Cui SUN Jin-jing YANG Xue-yong WAN Li ZHANG Zhong-hua ZHANG Hui-min College of Horticulture Qingdao Agricultural University/Engineering Laboratory of Genetic Improvement of Horticultural Crops of Shandong Province/Laboratory of Quality&Safety Risk Assessment for Fruit(Qingdao)Ministry of Agriculture and Rural AffairsQingdao 266109P.R.China Institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences/Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs/Sino-Dutch Joint Laboratory of Horticultural GenomicsBeijing 100081P.R.China

In situ mRNA hybridization(ISH)is a powerful tool for examining the spatiotemporal expression of genes in shoot apical meristems and flower buds of cucumber.The most common ISH protocol uses paraffin wax;however,embedding tissue in paraffin wax can take a long time and might result in RNA degradation and decreased signals.Here,we developed an optimized protocol to simplify the process and improve RNA sensitivity.We combined embedding tissue in low melting-point Steedman’s wax with processing tissue sections in solution,as in the whole-mount ISH method in the optimized protocol.Using the optimized protocol,we examined the expression patterns of the CLAVATA3(CLV3)and WUSCHEL(WUS)genes in shoot apical meristems and floral meristems of Cucumis sativus(cucumber)and Arabidopsis thaliana(Arabidopsis).The optimized protocol saved 4–5 days of experimental period compared with the standard ISH protocol using paraffin wax.Moreover,the optimized protocol achieved high signal sensitivity.The optimized protocol was successful for both cucumber and Arabidopsis,which indicates it might have general applicability to most plants.

关键词： cucumber in situ hybridization Steedman’s wax paraffin wax

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Combustion performance of hybrid rocket fuels loaded with MgB_(2)and carbon black additives

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Propulsion and Power Research 2023年第2期12卷 212-226页

作者： Yash Pal Sasi Kiran Palateerdham Sri Nithya Mahottamananda Subha Sivakumar Antonella Ingenito School of Aeronautical Sciences Hindustan Institute of Technology and ScienceChennai 603103India School of Aerospace Engineering University of Rome“La Sapienza”00138RomeItaly Department of Aerospace Engineering BS Abdur Rahman Crescent Institute of Science&TechnologyChennai 600048India

paraffin-based fuel has a great potential for several innovative missions,including space tourism,due to its safety,low environmental impact,high performance and low cost.Despite the fact that liquefying solid fuels increases the regression rate of hybrid rocket motors,incorporating energetic materials into solid fuel can still improve the performance.The objective and scope of this study is to increase the performance characteristics of the paraffin-based fuel by using magnesium diboride(MgB_(2))and carbon black(CB)additives.The cylindricalport fuel grains were manufactured with various additives percentages in mass(wt%:CB-2%and MgB_(2)-10%)and tested using a laboratory-scale ballistic hybrid motor under gaseous oxygen.The mechanical performance results revealed that adding CB and MgB_(2) improved the ultimate strength and elastic modulus of paraffin-based fuels.The addition of these fillers increased the hardness of fuel by developing a strong interaction in the paraffin matrix.Thermogravimetry(TG)results showed that CB inclusion improved the thermal stability of the paraffin matrix.The average regression rates of fuels loaded with CB and MgB_(2) were 32%and 52%higher than those of unmodified paraffin wax,respectively.The characteristic velocity efficiency was found in the range of 68%e79%at an O/F ratio of 1.5e2.6.The MgB_(2) oxidation/combustion in the paraffin matrix was described by a four-step oxidation process ranging from 473 K to 1723 K.Finally,a combustion model of MgB_(2) in the paraffin matrix was proposed,and four-step oxidation processes were discussed in detail.

关键词： Hybrid rocket paraffin wax Regression rate Magnesium diboride Mechanical properties

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Multifunctional HDPE/CNTs/PW composite phase change materials with excellent thermal and electrical conductivities

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Journal of Materials Science & Technology 2021年第27期86卷 171-179页

作者： Xiaolong Li Xinxin Sheng Yongqiang Guo Xiang Lu Hao Wu Ying Chen Li Zhang Junwei Gu Key Laboratory of Material Chemistry for Energy Conversion and Storage of Ministry of Education School of Chemistry and Chemical EngineeringHuazhong University of Science&TechnologyWuhan430074China Hubei Key Laboratory of Material Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science&TechnologyWuhan430074China Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter School of Materials and EnergyGuangdong University of TechnologyGuangzhou510006China Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an710072China School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang471023China

The risk of leakage and low thermal conductivity severely hinder the wide application of phase change materials(PCMs).In this work,the high-density polyethylene/carbon nanotubes(HDPE/CNTs)porous scaffolds were successfully fabricated via a sacrificial template method followed by the general melt blending and water solvent etching.Subsequently,a series of paraffin wax HDPE/CNTs/PW composite PCMs were obtained combined with the simple vacuum impregnation method.The obtained HDPE/CNTs porous scaffolds can effectively avoid the leakage of PW,meanwhile,the thermal conductivity and electrical conductivity of HDPE/CNTs/PW-3:7 are increased by 2.94 times and 13 orders of magnitude compared with the HDPE/PW-3:7 respectively,also,it exhibits high phase change enthalpy(153.95 J/g for melting enthalpy and 152.82 J/g for crystallization enthalpy).From the above perspectives,the HDPE/CNTs/PW-3:7 has promising potential value in the application of light-to-thermal conversion,electro-to-thermal conversion and thermal energy storage.

关键词： paraffin wax HDPE/CNTs porous scaffolds Phase change materials Thermal energy storage

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