Polymers
·
2023
·Vol. 15
·期 8
·1887
·
IF 5
Hui Fang,Guifeng Li,Kai Wang,Fangjuan Wu
This study investigates the effect of adding stearic acid (SA) on the thermal conductivity of polyamide 6 (PA6)/boron nitride (BN) composites. The composites were prepared by melt blending, and the mass ratio of PA6 to BN was fixed at 50:50. The results show that when the SA content is less than 5 phr, some SA is distributed at the interface between BN sheets and PA6, which improves the interface adhesion of the two phases. This improves the force transfer from the matrix to BN sheets, promoting the exfoliation and dispersion of BN sheets. However, when the SA content was greater than 5 phr, SA tends to aggregate and form separate domains rather than being dispersed at the interface between PA6 and BN. Additionally, the well-dispersed BN sheets act as a heterogeneous nucleation agent, significantly improving the crystallinity of the PA6 matrix. The combination of good interface adhesion, excellent orientation, and high crystallinity of the matrix leads to efficient phonon propagation, resulting in a significant improvement in the thermal conductivity of the composite. The highest thermal conductivity of the composite is achieved when the SA content is 5 phr, which is 3.59 W m−1K−1. The utilization of a composite material consisting of 5phr SA as the thermal interface material displays the highest thermal conductivity, and the composite also demonstrates satisfactory mechanical properties. This study proposes a promising strategy for the preparation of composites with high thermal conductivity.Keywords:thermal conductivity;polyamide;boron nitride;stearic acid
研究领域:
材料科学
·
热管理技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Pengfei Li,Ruiming Yin,Yunfei Bai,Yanhong Ding,Xiaofeng Zeng,Yongquan Li
To reduce the lattice oxygen content of Si 3 N 4 green bodies, samples were prepared using an N,N-dimethylacrylamide (DMAA) system. The endothermic and exothermic peaks are related to the decomposition of organic matter and the reaction between pyrolytic carbon and impurity oxides in the sintering process. Multi-step heat preservation during the thermal degreasing process reduced the carbon content and defects. The α→β phase transformation and aspect ratio of grains changed from 89.2% to 4.84:1 at 1640 °C to 96.3% and 7.80:1 at 1700 °C, respectively. The relative density, hardness, fracture toughness, and thermal conductivity of the Si 3 N 4 samples reached 98.5%, 1353 HV, 8.51 MPa·m 1/2 , and 97.1 W·m −1 ·K −1 , respectively. Pyrolytic carbon can react with SiO 2 , which reduces the content of the glass phase in the green body and affects the dissolution and precipitation process and lattice oxygen content. In the structure of the Si 3 N 4 sample, carbon particles with sizes of 100–500 nm and near-spherical shapes were observed. Intergranular-phase YMgSi 2 O 5 N was formed during the sintering process, which was conducive to improving the thermal conductivity. This article uses lower temperature and no pressure conditions to prepare Si 3 N 4 ceramics, which can provide reference for batch and low-cost production.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2023
·Vol. 15
·期 24
·4723
·
IF 5
Chao Chang,Bo Li,Baocai Fu,Xu Yang,Yulong Ji
Solar–thermal energy conversion and storage technology has attracted great interest in the past few decades. Phase change materials (PCMs), by storing and releasing solar energy, are able to effectively address the imbalance between energy supply and demand, but they still have the disadvantage of low thermal conductivity and leakage problems. In this work, new form-stable solar thermal storage materials by impregnating paraffin PCMs within porous copper–graphene (G–Cu) heterostructures were designed, which integrated high thermal conductivity, high solar energy absorption, and anti-leakage properties. In this new structure, graphene can directly absorb and store solar energy in the paraffin PCMs by means of phase change heat transfer. The porous structure provided good heat conduction, and the large surface area increased the loading capacity of solar thermal storage materials. The small pores and superhydrophobic surfaces of the modified porous G–Cu heterostructures effectively hindered the leakage issues during the phase change process. The experimental results exhibited that the thermal conductivity of the prepared form-stable PCM composites was up to 2.99 W/(m·K), and no leakage took place in the solar–thermal charging process. At last, we demonstrated that the PCM composites as an energy source were easily integrated with a thermoelectric chip to generate electric energy by absorbing and converting solar energy.Keywords:solar energy;phase change materials;graphene;thermal conductivity
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
PubMed
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2021
·Vol. 222
·期 10
·2000418
·
IF 2.527
Haoting Zheng,Kun Wu,Weilong Chen,Bingfei Nan,Zhencai Qu,Mangeng Lu
A series of copolymers of poly3-alkylthiophene (PTm) with different side chain lengths and copolymers of 3-butylthiophene and 3-butoxythiophene (PTDx) with different ratios are synthesized by oxidative polymerization. As the length of the side chain decreases, WAXD patterns of PTm show an increase in crystallinity. An increment of 50% in thermal conductivity is observed and the maximum thermal conductivity reaches to 0.320 Wm –1 K –1 . For PTDx, as the proportion of 3-butoxythiophene increases, the UV spectrum appears red-shifted, indicating an enhanced degree of p-π conjugation. The thermal conductivity of PTDx is increased from 0.340 to 0.374 Wm –1 K –1 , which is around twice that of traditional thermoplastics. Molecular dynamics (MD) is used to simulate the changes in the volume and dihedral angle overlap of the polymer at different temperatures, and achieves the same result as the experiment. MD simulations and experimental measurements have shown that reducing steric hindrance and enhancing p-π conjugation can increase the thermal conductivity of the polymer. Young's modulus of PTDx (around 1.86 GPa) is lower than that of conventional plastics, and its flexibility makes it more versatile.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
Case Studies in Thermal Engineering
·
2021
·
IF 4.724
Jing Fan,Han Mu,Chang Gao,Fenhong Song
Recently, biodiesel is considered as a biodegradable, renewable and high-potential fuel which could be used directly in tradition internal combustion engines. Fuel’ transport properties in high pressure are required to model the process of fuel spray, atomization and combustion accurately. This work, three ethyl esters’ liquid thermal conductivity (biodiesel compounds) in the liquid phase was measured by an experiment system which is established based on a transient hot-wire method with a bare platinum hot wire. The measurements were conducted at the temperatures ranging from 292 K to 372 K and pressure up to 15 MPa. The combined expanded uncertainty of the measurement was estimated to be ±2.0% (in the 0.95 confidence level). For interpolation, the relationship between measured results with temperature and pressure were correlated as a polynomial function, and the maximum deviation of correlations were less than 0.30%.
研究领域:
能源科学
·
物理化学
✓ 已验证
DOI
高影响因子
Nano Energy
·
2020
·
IF 16.602
Boyi Wang,Shuqi Zheng,Qing Wang,Zhiliang Li,Juan Li,Zipei Zhang,Yue Wu,Bensheng Zhu,Siyu Wang,Yuxuan Chen,Liqiang Chen,Zhi-Gang Chen
In this study, we develop a synergistic modulation of the thermal conductivity and power factor of Cu 3 SbSe 4 -based materials through Sn and Zr or Hf co-doping by using a facile microwave-assisted solvothermal method. A series of Cu 3 Sb 1-x M x Se 4 (M = Zr or Hf, x = 0, 0.02, 0.04, 0.06 and 0.08) compounds are firstly synthesized through the microwave-assisted solvothermal method combined with spark plasma sintering (SPS) process. The effect of Zr and Hf doping on the thermoelectric properties of Cu 3 Sb 1-x M x Se 4 (M = Zr or Hf) has been investigated. With increasing the content of Hf and Zr, the thermal conductivity of Cu 3 Sb 1-x M x Se 4 (M = Zr or Hf) is obviously decreased to 0.518 Wm −1 K −1 of Cu 3 Sb 0.92 Hf 0.08 Se 4 and 0.433 Wm −1 K −1 of Cu 3 Sb 0.92 Zr 0.08 Se 4 at 623 K, respectively. In addition, Sn doping further improves the low electrical conductivity and boosts the power factor, yielding a peak zT value of ~0.82 of Cu 3 Sb 0.91 Sn 0.03 Hf 0.06 Se 4 at 623 K, which is ~228% higher than that of the pristine Cu 3 SbSe 4 . Our work provides a new methodology for the decoupling of thermal and electrical properties of the Cu 3 SbSe 4 -based thermoelectric materials .
研究领域:
材料科学
·
热电材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
This work reports the two-step sintering method and thermal conductivity of Si 3 N 4 doped with 1.5 wt% MgO and varied contents of ZrH 2 in the range of 0-5 wt%. The metal hydride reduction reaction in the first step sintering allows the in situ generations of ZrO 2 and the elimination of native SiO 2 . A smaller amount of liquid phase with reduced oxygen content was produced during the second step sintering as a result of the replacement of ZrO 2 by ZrH 2 . With the aid of ZrH 2 as an oxygen getter, the native oxygen in those ZrH 2 -doped samples was removed via a route of SiO 2 →ZrO 2 →SiO(g). Consequently, the densified Si 3 N 4 ceramics with larger volume percent of elongated purified β-Si 3 N 4 grains and less glassy phase were obtained. Ultimately, the optimal thermal conductivity of 116.4 W m −1 K −1 was achieved after sintered at 1900 °C for 12 h by using 3 wt% ZrH 2 and 1.5 wt% MgO as additives.
研究领域:
材料科学
·
热物理
✓ 已验证
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2020
·
IF 6.444
Yingchun Liu,Kun Wu,Maoping Lu,Enxiang Jiao,Hangzhen Zhang,Jun Shi,Mangeng Lu
Low thermal conductivity (TC) and poor flame retardancy of graphene oxide (GO) have limited its application in thermal management. Herein, a facile strategy is developed to fabricate flexible and free-standing graphene/MXene (GM) films by filtration of MXene and GO dispersions, followed by reduction and thermal welding. As results, interlamellar insertion of MXene into graphene has occurred and optimized interface was constructed between MXene and graphene. According to Y. Agari’s semi-empirical model and modified Maxwell-Garnett effective medium approximation, demonstrating that an optimized interface between MXene and graphene is conducive to heat conduction, and reduces the interface scattering. In-plane TC thus reached to 26.49 Wm −1 K −1 , and the thermal boundary resistance decreased to 8.81 × 10 −10 from 1.54 × 10 −8 m 2 KW −1 . GM films also present excellent flame retardancy (peak heat release is ~10 Wg −1 ) and it still maintained initial shape after combustion. Using as-prepared GM films as heat dissipation, we demonstrate its potential usefulness in electronic device-cooling applications.
研究领域:
材料科学
·
热管理技术
✓ 已验证
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 13
·1946
·
IF 4.7
Jing Fan,Yuting Pan,Dazhi Gao,Hongwei Qu
Deep eutectic solvents (DESs) are complex substances composed of two or three components, wherein hydrogen bond donors and acceptors engage in intricate interactions within a hydrogen bond network. They have attracted extensive attention from researchers due to their easy synthesis, cost-effectiveness, broad liquid range, good stability, and for being green and non-toxic. However, studies on the physical properties of DESs are still scarce and many theories are not perfect enough, which limits the application of DESs in engineering practice. In this study, twelve DESs were synthesized by using choline chloride and betaine as HBAs, and ethylene glycol, polyethylene glycol 600, o-cresol, glycerol, and lactic acid as HBDs. The variation rules of their thermal conductivity and viscosity with temperature at atmospheric pressure were systematically investigated. The experimental results showed that the thermal conductivity of the 1:4 choline chloride/glycerol solvent was the largest at 294 K, reaching 0.2456 W·m−1·K−1, which could satisfy the demand for high efficiency heat transfer by heat-transferring workpieces. The temperature–viscosity relationship of the DESs was fitted using the Arrhenius model, and the maximum average absolute deviation was 6.77%.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2012
·
IF 1.693
Yuan-Yuan Che,Jian Shen,Jun-Chao Zhou,Chao-Hong He
The thermal conductivity of ammonium sulfate + water, ammonium nitrate + water, and ammonium sulfate + ammonium nitrate + water is of great significance in the national defense industry and military engineering for manufacturing of various energetic chemicals. The measurements, covering a temperature range from (278.15 to 333.15) K, have been performed by a transient hot-wire technique over a wide range of concentrations. The densities of ternary aqueous solutions of ammonium sulfate + ammonium nitrate are also presented at the same temperature covering different portions of ammonium sulfate and ammonium nitrate. The thermal conductivities of binary aqueous solutions of ammonium salts are correlated by polynomial functions in terms of temperature and weight fraction for the purpose of interpolation. The Aseyev equation in terms of weight fraction is also used to represent the thermal conductivities of ternary mixtures of these compounds. The ideal mixing rule of Young has been successfully applied to correlate the ternary densities of aqueous ammonium sulfate + ammonium nitrate solutions based on relevant binary solution properties. The agreement between the correlation and the experimental data is pretty good.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
The effect of the GdH 2 on the shrinkage behavior, microstructure, thermal conductivity , and flexural strength was investigated. The pre-sintering enables the elimination of native SiO 2 and the simultaneous formation of Gd 2 O 3 . The N/O ratio in the liquid phase was increased because of the increasing Gd 2 O 3 /SiO 2 ratio, resulting in the restricted shrinkage during gas pressure sintering. The high N/O ratio in the liquid phase benefits not only the nucleation and growth of β-Si 3 N 4 but also the removal of lattice oxygen, leading to the increase of thermal conductivity . Although the replacement of Gd 2 O 3 by GdH 2 leads to enhanced flexural strength at low temperature, it tends to reduce the flexural strength at high temperature. This variation related largely to the exaggerated bimodal microstructure. This work signifies that GdH 2 is an effective sintering additive for obtaining Si 3 N 4 ceramics with both high flexural strength and high thermal conductivity.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2014
·
IF 2.307
Yinsheng Li,Jie Yin,Haibo Wu,Ping Lu,Yongjie Yan,Xuejian Liu,Zhengren Huang,Dongliang Jiang
In order to attain high thermal conductivity , SiC was doped with ultra-low amounts of B and C as sintering additives using boric acid together with d -fructose as boron–carbon sources. The contents of in situ generated B and C were both tailored as low as 0.4 wt.%, which can significantly reduce the impurities induced phonon scattering effect. The SiC ceramics were pressureless densified at 2150 °C for 1 h, and some samples experienced subsequent annealing at 1950 °C for 4 h. High thermal conductivities of 180.94 W/(m K) for the as-sintered SiC ceramics and 192.17 W/(m K) for the annealed specimens at room temperature were achieved. The reasons for the high thermal conductivity in the polycrystalline SiC ceramics were specified, based on the close correlation with microstructure.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）