Materials Advances
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2023
·Vol. 4
·期 9
·2119-2126
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IF 5
Ran Chen,Liang Zhao,Yannanqi Li,Jian Li,Pei Chen,Xinbing Chen,Zhongwei An
A series of tolane liquid crystals terminated by but-3-enyl with high performance (such as high clearing point, low melting point, high birefringence Δn, low viscosity γ1, and broad nematic phase interval) were designed and synthesized in accordance with the phase-only liquid-crystal-on-silicon (LCoS) device requirements for AR displays. The effects of the lateral fluoro-substituent, central alkyne bond, terminal group, and flexible n-alkyl chain on the thermal properties were systematically investigated, and density functional theory (DFT) calculations of molecular conformation and aspect ratio were used to corroborate the experimental results. Further, their properties of phase transition temperature, birefringence, and viscosity were comprehensively evaluated in two typical LC mixtures (001, P02-F). The results indicate that our target compounds can effectively lower the melting point, broaden the working temperature interval, and maintain a high Δn and low γ1 for three LC mixtures. One new LC mixture by employing compound 2TFV as a LC dopant exhibited a high Δn (∼0.26), moderate γ1 and dielectric anisotropy (∼6.3), and broad temperature adaptability (−31.3 °C to 91.3 °C), and achieved 2.08π phase modulation, 5 V operation voltage, and 2.89 ms response time at 40 °C in a reflective LCoS device.
研究领域:
材料科学
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显示技术
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光学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2018
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IF 4.229
Fei Xiao,Yanpei Guo,Rongjie Yang,Jianmin Li
A series of activated Mg-based alloys with low-melting-point metals (Zn, Sn, Bi, and In) are prepared by ball milling and characterized by scanning electron microscope and X-ray diffraction. Their hydrogen generation properties are systematically investigated in seawater and methanol. The results demonstrate that the addition of low-melting-point metals can significantly accelerate the reaction of magnesium with seawater and methanol. The alloy Mg-10%In exhibits the excellent hydrolysis properties among all the samples with the maximum hydrogen generation rate of 7.4 mL g −1 s −1 and the hydrogen conversion yield of 93% at 30 °C in seawater. The excellent hydrolysis performance of Mg-10%In can be attributed to its lower activation energy , lower corrosion potential , and higher corrosion current density. Moreover, the active preservation method of activated Mg alloys by coating dioctyl sebacate is studied.
研究领域:
材料科学
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能源化学
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产品关联
DOI
高影响因子
APPLIED THERMAL ENGINEERING
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2022
·
IF 6.465
Yu Zhao,Zhengguo Zhang,Ziye Ling,Xuenong Gao,Xiaoming Fang
Thermal interface materials that possess high thermal conductivity and can reach low thermal impedance during service, are highly desirable for chip heat dissipation systems, especially when cooling high-power chips. Herein, a novel thermal pad was developed by combining low melting point alloy having metal-level thermal conductivity and liquid-like rheological property with expanded graphite possessing large pore volume and high thermal conductivity. Specifically, the alloy 62.5Ga21.5In16Sn was modified by the trace-oxidation method to obtain oxidized alloy, followed by adsorbing into expanded graphite and then molding and pressing to fabricate the thermal pad. It is found that the oxidation treatment resulted in the generation of refractory metal oxides Ga 2 O 3 and SnO 2 within the alloy, thereby preventing the leakage of the alloy from the composite thermal pad. Impressively, the optimal low melting point alloy/expanded graphite composite thermal pad, prepared at the oxidation duration of 24 min, expanded graphite mass fraction of 4 % and compact density of 3.125 g/cm 3 , reached a thermal conductivity of as high as 26.94 W/m·K and a thermal impedance of as low as 0.42 K·cm 2 /W, along with exhibiting a good shape-stability. More significantly, when employed into a simulative desktop CPU cooling system, this thermal pad exhibited 36.78 % higher cooling efficiency under the forced air convection, extended ten times in the time for the chip to reach the upper limit temperature (100 ℃) under the natural air cooling, and benefited to the chip to fight with the pulse-type instantaneous thermal shock, as compared to the commercial thermal pad. These excellent characteristics and good heat dissipation performance make the low melting point alloy/expanded graphite composite thermal pad show great potential for use in chip thermal management systems.
研究领域:
材料科学
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热管理技术
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DOI
高影响因子
Polymers
·
2022
·Vol. 14
·期 21
·4700
·
IF 4.967
Xinyang Zhang,Xinyang Wang,Jian Li,Shuo Zhang,Qingxin Zhang,Xiaoyan Yu
A phthalonitrile monomer (DPTP) containing pyridine with sulfide bonds was prepared and cured into polymers using different curing agents under the same temperature-programmed process. We characterized and comprehensively evaluated the effects of different curing agents on the thermal and thermomechanical properties of phthalonitrile resin, showing that the DPTP monomer cured with naphthalene-containing curing agent exhibited the best performance among the three polymers. Differential scanning calorimetric (DSC) investigation manifested that the melting point of the DPTP monomer was 61 °C, with a processing window of about 170 °C, suggesting the presence of a wide processing range. Thermogravimetric analysis (TGA) demonstrated the outstanding heat resistance,T5%, of 460 °C in nitrogen, at the same time demonstrating superior long-term stability compared with other commonly used polymer materials, which proves the long-term usage under high temperatures of 300 °C. Dynamic mechanical analysis (DMA) revealed that the storage modulus at 50 °C was 3315 MPa, and the glass transition temperature (Tg) of the polymer was more than 350 °C. Therefore, DPTP resins have favorable thermal stability as well as prominent thermomechanical properties.Keywords:phthalonitrile resin;processing window;low melting point;long-term stability
研究领域:
材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
HIGH PERFORMANCE POLYMERS
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2020
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IF 1.568
Ke Li,Hua Yin,Kun Yang,Pei Dai,Ling Han,Riwei Xu
Designing novel low-melting, high-rigidity phthalonitrile resin is of great significance in the current context of development. In this study, rigid spirocycle acetal structure was introduced into phthalonitrile to reduce the melting point and maintain their thermal stability. The chemical structure of resins was confirmed by nuclear magnetic resonance (NMR) spectrometry, matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry and Fourier-transform infrared (FTIR) spectroscopy. The curing behaviors were studied by differential scanning calorimetry (DSC). Thermal stability and mechanical properties of the cured resins were investigated by dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The processability was studied by rheological analysis. The results indicated the three monomers had a low melting temperature, wide processing windows and low viscosities. These polymers did not exhibit Tg from room temperature to 400°C, exhibited superb dynamic mechanical property and thermal stability.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES
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2023
·
IF 3.4
Weiwei Zhang,Zheng Zhang,Hao Liu,Jianqiang Wang,Fangcheng Duan,Ziwen Lv,Wentong Chen,Xinjie Wang,Mingyu Li,Chuantong Chen,Hongtao Chen
Adequate mechanical and electrical properties and long-term reliability are critical in conductive adhesive interconnects. In order to improve the electrical and mechanical properties of isotropic conductive adhesives (ICAs), reduce contact resistance and enhance the aging resistance of ICAs, the effects of low melting point SnBi58 alloy on the properties of ICAs were studied. The low melting point SnBi58 alloy formed metallurgical bonds between conductive fillers , as well as between the ICAs and a Cu substrate and not only improved the electrical conductivity and mechanical properties of ICAs, but also reduced the contact resistance shift of ICAs effectively. It was found that when the mass ratio of SnBi58 alloy in conductive fillers was maintained at 20 wt%, the bulk resistivity of ICAs reached 4.8 × 10 −4 Ω cm, the shear strength of ICAs was 27.71 MPa, and the contact resistance shift of ICAs was 7% after aging. In addition, better bulk resistivities and higher shear strengths of ICAs were achieved after aging at 85 °C/85%RH.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
ENERGY
·
2015
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IF 4.844
Weijuan Yang,Tianyou Zhang,Junhu Zhou,Wei Shi,Jianzhong Liu,Kefa Cen
Aluminum (Al) is a promising hydrogen carrier. Continuous reaction of pure Al and water (H 2 O) cannot proceed smoothly because Al particles are covered with a protective oxide layer . Thus, 20% Mg, Li, Zn, Bi, and Sn content were added as additives to Al–H 2 O reaction at high temperature. Thermogravimetric experiments were conducted to determine the reactivity of pure Al and five other samples with additives in a vapor atmosphere. Experiments indicated that Mg and Li drove the Al–H 2 O reaction, but Zn, Bi, and Sn had little effect. Thus, Mg and Li were selected as activators in the hydrogen generation of the Al–H 2 O reaction conducted on a specially designed experimental facility. Hydrogen was monitored in the reaction of Al-based composites with H 2 O vapor in real time. Among them, Al–20%Li achieved the fastest hydrogen generation rate (309.74 ml s −1 g −1 ) and the largest hydrogen amount (1038.9 ml g −1 ). XRD (X-ray diffraction), SEM (scanning electron microscopy), and TEM (transmission electron microscopy) were used for product analyses to identify the influence of adding Mg and Li. This method of Al energy utilization may be used in underwater propulsion systems .
研究领域:
能源科学
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材料科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
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2017
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IF 0.736
X. Guan,P. Luo,S. J. Dong
Aluminum (Al)-based materials composited of different low melting point materials were prepared by mechanical ball-milling. Hydrogen production using these materials was investigated to help resolving the safety issues associated with the storage and transportation of hydrogen. The phase composition and microstructure of the Al-based composited materials were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. As observed in this study, the addition of low melting point metals (such as Sn, Bi and In) helped to lower the initial Al-water reaction temperature and to increase the yield in the production of hydrogen. Samples of optimized compositions, Al–6% Sn–4% Bi and Al–6% Sn–4% In, were found to exhibit high hydrogen production yields of up to 448 and 515 mL, respectively. Meanwhile, their hydrogen generation rates were increased.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
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2022
·
IF 11.322
Jianyu Xu,Qing Liu,Hongda Guo,Miaomiao Wang,Zongjin Li,Guoxing Sun
Concrete usually possesses drawbacks of low flexural strength and prone to crack. In this research, Field's metal with a low melting point was introduced into the cement matrix to improve the crack resistance, thereby enhancing the flexural strength and toughness of cement matrix. A comparative study was conducted to elucidate the effects of the Field's metal on the mechanical behavior , microstructure, capillary permeability, hydration, and electrical properties of cement paste . By tuning the fraction of the Field's metal, the flexural strength and toughness showed the highest increase of 41% and 94%, respectively. The enhancement of flexural properties can be attributed to the filling effect of the low melting metal into the voids in the matrix, bridging effect of metal particles and the higher flexural strength as well as the higher fracture toughness of the metal. This approach opens a new research direction for the design and application of an innovative functional building materials .
研究领域:
土木工程
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建筑材料
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产品关联
DOI
高影响因子
INTEGRATED FERROELECTRICS
·
2022
·
IF 0.836
Zhifen Fu,Chang Li,Chen Chen,Yubin She,Zhongyi Yang
low-fired Li2ZnTi3O8 ceramics were fabricated by a solid-state reaction method for developing LTCC applications. TLBBC mixed sintering aid was used to improve the sintering stability. X-ray diffraction analyses demonstrated that specimens corresponded well to the cubic crystal symmetry structure of Li2ZnTi3O8, accompanying with a little of impure phase Ca3Ti2O7 and LiBO2. The sintering temperatures of Li2ZnTi3O8 ceramics were lowered to 950 °C due to the formation of low melting point LiBO2. At x = 3, Li2ZnTi3O8 ceramics exhibited an microwave dielectric properties with εr = 21.0, tanδ = 5.76 × 10−4, Q × f = 14750 GHz, τf = −11.5 ppm/°C at 950 °C.
研究领域:
材料科学
·
电子材料
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产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2024
·
IF 8.3
Chengan Ma,Fei Yan,Shengtao Dai,Jintang Duan,Yuhui Ao,Gang Li,Gaosong Wang,Qingyu Zhou,Feng Bao,Liu Liu
In this study, a bio-based polyarylene ether ketone (bio-PAEK) was synthesized to prepare water-based sizing agents for enhancing the interfacial adhesion between carbon fiber (CF) and matrix. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results indicated that the bio-PAEK exhibited good thermal properties. To improve the processability and reduce the processing temperature, PAEK with a low melting point (LMPAEK) was also used as the matrix resin . The glass-transition temperature (T g ) of LMPAEK was slightly higher than that of polyether ether ketone (PEEK), but its melting temperature (T m ) was lower 48.5 °C. A strong interface was created after introducing sizing agents onto the CF surface due to good compatibility between fibers and matrix. The interlaminar shear strength (ILSS), interfacial shear strength (IFSS) and flexural strength of CF2/LMPAEK composites increased by 54.7 %, 56.0 % and 46.6 %, respectively, compared with the untreated composites. This study provided a novel approach to prepare water-based bio-PAEK sizing agents for CF composites with a low melting point matrix to be applied in additive manufacturing .
研究领域:
材料科学
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复合材料工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Yan Liang,Yongqing Wang,Junjie Qian,Li Liu,Yulong Yang,Mingmin Bai,Haotian Zheng
Silicon carbide (SiC) ceramic membrane supports, as critical components of ceramic membrane filters, must exhibit outstanding performance in mechanical properties, porosity, and chemical stability. In this study, MoO₃ was employed as a sintering aid, with SiC and α-Al₂O₃ serving as raw materials and walnut shell powder as a pore-forming agent. The effects of varying sintering temperatures (1250–1400°C) and MoO₃ contents on the properties of SiC porous ceramic membrane supports were systematically investigated. Special emphasis was placed on elucidating the mechanisms by which MoO₃ addition influences porosity, flexural strength, pore size distribution, and chemical stability. Experimental results demonstrate that the introduction of MoO₃ facilitates low-temperature sintering of SiC supports through a dissolution-precipitation mechanism. This process promotes the formation of mullite whiskers that reinforce interparticle necking regions while enhancing the uniformity of neck connections. Optimal performance was achieved at 1350°C with 8 wt% MoO₃ addition, yielding a bending strength of 37.01 ± 1.72 MPa, average pore size of 1.735 μm, most probable pore size of 1.7 μm, open porosity of 39.12 %, and exceptional corrosion resistance. This work establishes both theoretical foundations and practical strategies for low-temperature fabrication of high-performance SiC porous ceramics, while expanding the application potential of molybdenum-based sintering aids in structure-function integrated ceramic materials.
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）