THERMOCHIMICA ACTA
·
2017
·
IF 2.236
Ming Huang,Yan Luo,Yi Zhong,Min Xiao,Jiancan Hu
In this paper, a new type of microcapsulated phase change materials (BS-TD/PALMA microPCMs) with butylstearate (BS) and tetradecanol (TD) as binary cores and poly (allyl methacrylate) (PALMA) as shell, was prepared for thermo-regulated fibers. The surface morphology, particle size distribution, thermal properties and thermal stability of the resulting microcapsules were investigated. The results showed that the melting temperature and mean diameter of BS-TD/PALMA microPCMs were 20.1-32.6 °C and 1.3 ± 0.3 μm, respectively. The latent heat and encapsulation efficiency reached up to 73.3 J g −1 and 76.4 wt.%, respectively. BS-TD/PALMA microPCMs displayed good thermal stability. They were greatly favorable for the application to thermo-regulated fibers.
研究领域:
材料科学
·
纺织工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 107
·期 6
·4373-4382
·
IF 3.5
Na Li,Qing Zhao,Bo Zhang,Huimin Chen,Aimin Chang,Zhilong Fu
The cold-sintering process (CSP) uses a transient low-temperature solvent, such as water or water with dissolved solutes consistent with the ceramic composition, to achieve functionalization at lower temperatures via the dissolution and precipitation principle. Here, during the CSP, the use of molten NaOH as a flux solvent promoted the rearrangement and precipitation of CaYNbMnO 7 particles. CaYNbMnO 7 ceramics were successfully obtained at 350°C and under a uniaxial pressure of 700 MPa. The ceramic was not a single-phase structure but consisted of a cubic-phase structure and a layered perovskite structure. To verify the high-temperature thermal stability of CaYNbMnO 7 ceramic prepared at 350°C, a comparative study was conducted with conventional sintering (CS). Results indicate that the ceramics obtained by CSP and CS have negative temperature coefficient characteristics. The cold-sintered ceramic has a wider temperature range and better aging stability. (The minimum value of the aging coefficient is ∼2.49%.) Simultaneously, CSP is beneficial for promoting the linearization of the relationship between the logarithm in the resistivity (ln ρ ) and the reciprocal for the absolute temperature (1000/ T ) in the ceramic. However, the CSP has little effect on the material constant B and thermal activation energy E a of the ceramic, providing a basis for the low-temperature synthesis of high melting point thermosensitive ceramics.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Meng Zhao,Xiaorui Ren,Jun Yang,Wei Pan
A series of ThO 2 -doped Y 2 O 3 stabilized ZrO 2 monolith compounds were prepared and investigated. The bigger ionic radius of Th 4+ substitutions dilutes the average oxygen coordination to the cations, which is the determinant factor of the phase stability. Therefore, ThO 2 incorporation has a strong impact on the phase composition, and consequently on the thermo-mechanical properties of the specimens. The metastable t′ phase was stabilized in light-doped specimens with a decreasing tetragonality while the thermodynamic equilibrium t phase and the related martensitic t–m phase transformation were absent in ThO 2 -doped specimens. Additionally, lower thermal conductivity was also achieved due to the substitutional phonon scattering effect. Considering the phase stability and thermo-mechanical properties, ThO 2 -doped Y 2 O 3 stabilized ZrO 2 compounds may be promising candidates for thermal barrier coatings although further research may be needed to improve their mechanical properties.
研究领域:
材料科学
·
热物理
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Liuyan Yin,Xingui Zhou,Jinshan Yu,Honglei Wang
Ceramic foam with excellent mechanical performance, high thermal conductivity and high surface area-to-volume ratio is thought to have great potential in heat exchanger application. In this study, silicon nitride (Si 3 N 4 ) foams with ultrathin cell walls were prepared by using a protein foaming method via increasing the air fraction of foamed slurry. Cell thickness of these Si 3 N 4 foams was only 2–3 µm and the pores in the Si 3 N 4 foams fabricated here exhibited polyhedral shapes. Thermal conductivities of these Si 3 N 4 foams ranged from 2.427 W m −1 K −1 to 3.154 W m −1 K −1 , whereas compressive strengths of these Si 3 N 4 foams are in the range from 12.85 MPa to 19.99 MPa. Moreover, compressive load–displacement curves of the Si 3 N 4 foams generally exhibit cellular behavior.
研究领域:
材料科学
·
工程热物理
✓ 已验证
DOI
高影响因子
Cell Reports Physical Science
·
2024
·
IF 7.9
Desong Fan,Jun Fang,Wenyi Tong,Wenqing Du,Qiang Li
Ultrathin heat pipes (UHPs) have attracted tremendous attention in recent years. However, fabricating UHPs with high heat-transfer efficiency and low thermal expansion remains a challenge. Here, we report a design of an inverse opal complex wick for UHPs. The design enables the wick to have abundant random micropores for the transportation of vapor and ordered nanopores for the return of condensate. With the assistance of a Cu/MoCu/Cu shell, the UHP with a thickness of 0.985 mm can maintain a low coefficient of thermal expansion (7.3E−6 /K) and allow a gallium nitride (GaN) chip to work at a heat flux of 208 W/cm 2 . When the liquid filling ratio reaches 54%, a lower thermal resistance of 0.8 K/W and a higher thermal conductivity of 11,076 W/(m⋅K) are realized. This study demonstrates the successful fabrication of high-performance UHPs, promoting the development of inverse opal wicks from materials to devices.
研究领域:
材料科学
·
热能工程
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Miao He,Yuting Xie,Zihui Ni,Xuzhong Zeng,Hebin Bao,Xiaodi Wu,Li Liu,Xueming Li,Qihui Wang
Based on the superior exothermic properties, Al/CuO nanothermites are considered as one of the most promising energetic materials in recent years. In this work, the CuO nanospheres with particle size of 100–120 nm were successfully synthesized by a simple solution route and subsequent heat treatment, and used as oxidizer of Al/CuO nanothermites. The electrophoretic deposition kinetics of Al/CuO nanothermites were investigated in detail. Then, the morphology and composition of the as–prepared Al/CuO nanothermites were characterized by means of scanning electron microscopy (SEM), X–ray diffraction (XRD), X–ray photoelectron spectroscopy (XPS), and spectrophotometry. The results show that the electrophoretic deposition behavior of Al/CuO nanothermites is controlled by diffusion. Furthermore, there is a linear relationship between the equivalent ratio in the suspension (Ф d ) and the deposited film (Ф s ). The Ф d can be precisely adjusted by changing the electrophoresis parameters. When the equivalent ratio of Al/CuO nanothermites in the suspension is 1.5, the heat release of the sample can reach up to 1977 J/g. This work provides a new strategy for the preparation of nanothermites by electrophoretic deposition.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Biomass Conversion and Biorefinery
·
2024
·
IF 3.5
Liang Miao,Wang Yiqun,Dai Shuiping,Hong Liu,Li Ruili,Xu Zhenyu,Su Jiakun,Zhang Junsong
Cigar is a kind of air-dried tobacco raw material with different physical structures and chemical compositions compared with flue-cured tobacco. The pyrolysis and thermal release characteristics of cigar tobacco are important for advancing their use in heat-not-burn cigarette. In this study, the thermal release behavior of cigar tobacco with different glycerol additions under heating conditions was analyzed by thermogravimetric technique as well as a self-built infrared rapid heating furnace combined with GC–MS analysis. The results showed that the thermal weight loss process of cigar tobacco could be divided into three stages. The addition of glycerol exhibited significant impact on pyrolysis process, especially in the stage II, accompanied by a decrease in T max , an increase in DTG max , and weight loss at this stage. Thermal release kinetic analysis of stage II by Coats-Redfern method showed an increased activation energy and pre-exponential factor. With the amount of glycerol addition increasing, the total aroma components released from cigar tobacco showed a trend of first increasing and then decreasing at both heating rates, and reached the highest level when the glycerol addition amount was 20%. By means of multi-factor analysis of variance, the significance of heating rate and glycerol addition as well as the optimum combination between them that could maximize the release of various types of aroma components was determined. This study may be beneficial for the reasonable utilization of cigar tobacco in related products.
研究领域:
烟草科学
·
热化学分析
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Jingjing Kong,Junjie Liu,Peiyu Jia,Ning Qi,Zhiquan Chen,Shan Xu,Nanwen Li
Two kinds of polyimide membranes 6F-AP and 6F-AP/DA (APAF:DABA=3:2) were synthesized and heated between 300–450 °C to study the effect of thermal treatment on the chain structure and gas transport performance of membranes. Fourier Transform Infrared (FI-IR) and X-ray diffraction (XRD) measurements show that heating causes rearrangement of polyimide into rigid polybenzoxazole which prevents the effective stacking of polymer chains leading to the increase of d-spacing and fractional free volume. Positron annihilation results confirm the increase of both size and number of free volume due to the thermal rearrangement. The addition of DABA monomer into 6F-AP causes crosslinking during heating, which results in tightening of the rigid chain spacing of benzoxazole, thus leading to slight decrease in the size and number of free volume. The increase in fraction free volume induced by thermal rearrangement can significantly improve the gas permeability of 6F-AP series membranes, which increases from 16.2 and 3.9 barrer to 271.4 and 200.3 barrer for H 2 and CO 2 , respectively, after increasing the heating temperature from 300 to 450 °C. But this is accompanied by a decrease in gas selectivity due to the increase in free volume size. Finally, by careful tailoring the free volume structure through thermal rearrangement and crosslinking, the 6F-AP/DA polyimide treated at 400 °C exhibits a H 2 permeability of 196.4 barrer and a H 2 /CH 4 ideal selectivity of 90, which is above the 2008 Robeson upper bound. Our results indicate that by designing the functional groups of the reaction monomer plus appropriate thermal treatment, the microstructure of polyimide membrane can be effectively adjusted for high-performance gas separation.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Frontiers in Energy Research
·
2022
·
IF 3.858
Cui Jiedong,Lu Pengbo,Li Yinghui,Xu Ke,Li Yang,Shen Haoyu,Liu Chaocheng,Zhang Tianyi,Liu Detao
The flexible and transparent film heaters (FTFHs) with the advantages of mechanical flexibility, portability, and excellent electrothermal performance, are key to the next generation portable, wearable heaters and thermal protection systems. However, the present flexible and transparent substrates of FTFHs are fabricated by typical plastic PET films, which suffer from poor interfacial adhesion with the thermally conductive materials. In this work, the transparent regenerated cellulose fibers made of completely dissolved in NMMO solution followed by regeneration process is presented to disperse and support carbon nanotubes (CNTs) by a vacuum-dewatering process. In the presence of cellulose fibers, these CNTs have strong hydrogen bonding properties in the dehydration-deposition process and thus respond to tight intertwining structures in fibrous composites. The resulting regenerated cellulose fibers exhibit high optical transparency of 88% (@550 nm) and good mechanical properties (30 MPa). Interestingly, the FTFHs show a rapid heating response, high generation temperature, and resistance stability for up to 2 h. The FTFHs made with earth-abundant, cost-effective, and recyclable materials, have excellent potential in the areas of green flexible and transparent film heaters.
研究领域:
材料科学
·
能源技术
·
纳米技术
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2021
·
IF 3.383
Slimane Abdous,Mehdi Derradji,Oussama Mehelli,Raouf Belgacemi,Azzedine Khadraoui,Yacine Laichi,Hamza Djerra,Noureddine Ramdani,Wenbin Liu
In this study, three new energetic benzoxazine monomers were synthesized via a one-step Mannich reaction process involving the incorporation of explosophore nitro groups (NO 2 ) in different positions (ortho, meta and para) into the monomer backbone. The molecular structures of the synthesized monomers were confirmed by FTIR, 1 H and 13 CNMR techniques. The curing behavior, thermomechanical properties and the thermal stability were assessed by DSC-TGA analyses. All monomers displayed two exothermic peaks related to the polymerization and degradation steps except 4-NBZ that present the polymerization and the degradation phenomena through one unique exotherm pic. The energetic performances were evaluated by the determination of the heat of combustion using a bomb calorimeter in an oxygen atmosphere. The results indicated that the para position provided the benzoxazine monomers with a high calorific value comparable to that of the nitrocellulose (about 10.401 kJ/g). Meanwhile, the aforementioned monomer was found to ignite at a temperature of about 267 °C. Overall, this study showed that the ease of synthesis of the benzoxazine resins via Mannich reaction can be further extended the energetic field and further researches are undergoing to fully unravel the potential of these exceptional materials.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·Vol. 47
·期 5
·6548-6553
·
IF 3.83
Chuangchuang Ruan,Hongzhang Song,Mengmeng Fan,Haoshan Hao,Shaohui Liu
Misfit-layered oxides Ca 3 Co 4 O 9+δ + z wt% SiC ( z = 0.00, 0.025, 0.05, 0.1, 0.2) samples were synthesized using solid-state sintering method and the effects of SiC nanoparticles diapersion on the thermoelectric properties were investigated. Thermoelectric properties of Ca 3 Co 4 O 9+δ + z wt% SiC ( z = 0.00, 0.025, 0.05, 0.1, 0.2) were investigated up to 923 K. Compared with pure sample, the electrical resistivity of SiC-added samples reduces, for Ca 3 Co 4 O 9+δ + z wt% SiC ( z = 0.00, 0.025, 0.05, 0.1, 0.2) ceramic samples with x ≤ 0.05, the electrical resistivity decreases with increasing SiC nanoparticles adding amounts. And, the electrical resistivity exists transition from semiconductor to metal conduction mechanism. While, the thermal conductivity also decreases due to the addition of SiC nanoparticles . As a result, the Ca 3 Co 4 O 9+δ + 0.2 wt% SiC sample had the lowest thermal conductivity of 1.47 W/Km at 923 K, which was 18.4% lower than that of the Ca 3 Co 4 O 9+δ sample. The ZT value of Ca 3 Co 4 O 9+δ + 0.05 wt% SiC can reach 0.218, which is 40.9% higher than the pure Ca 3 Co 4 O 9+δ sample.
研究领域:
材料科学
·
凝聚态物理
·
无机非金属材料
·
能源材料
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Shuang Yang,Huazhi Gu,Zhouhui Li,Ao Huang
As a promising thermoelectric material, aluminum-doped zinc oxide (AZO) exhibits high thermal conductivity , which limits its use in high-temperature thermoelectric applications. Here, we report an effective route for forming a porous architecture and nanoinclusions by introducing nano-SiC to reduce the thermal conductivity . The simultaneous formation of a porous architecture and nanoinclusions promotes enhanced phonon scattering, resulting in fairly low thermal conductivity of approximately 3.3 W⋅ m −1 ⋅ K −1 . Meanwhile, the Seebeck coefficient shows the significant improvement due to energy filtration effect caused by porous architecture and nanoinclusions. The resultant dimensionless figure of merit of approximately 0.2 at 1050 K was 1.5 times higher than that of AZO ceramic without nano-SiC, which is attributed to the combined factors of increased Seebeck coefficient and reduced thermal conductivity .
研究领域:
材料科学
·
热电材料
·
纳米结构材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）