ADVANCED ENGINEERING MATERIALS
·
2022
·Vol. 25
·期 5
·2200160
·
IF 4.122
Zhigang Zheng,Hongyu Wang,Chengfeng Li,Xinglin Chen,Dechang Zeng,Shengfu Yuan
The effect of quenching temperature on phase structure and magnetocaloric properties of the Mn 0.975 Fe 0.975 P 0.5 Si 0.5 alloys are systematically studied by X-ray diffraction, scanning electron microscope, differential scanning calorimetry, and vibrating sample magnetometer. The Mn 0.975 Fe 0.975 P 0.5 Si 0.5 alloys quenched at 1323, 1073, 873, and 673 K are all crystallized in the hexagonal Fe 2 P-type phase and the phase fraction of the Fe 2 P phase increases with the decreases of quenching temperature. As the quenching temperature decreases from 1323 to 673 K, the crystal lattice of alloys expands and the atoms' occupation is more ordered, while the saturation magnetic moment increases from 3.71 to 4.10 μ B f.u. − 1 The values of thermal hysteresis increase linearly from 30 to 41 K when the quenching temperature is down to 673 K. This enhancement of the first-order magnetic transition (FOMT) yields the maximum value of magnetic entropy change at 5 T increasing by 36%. To obtain excellent comprehensive properties for (Mn,Fe) 2 (P,Si) alloys, the methods of doping B element in the Mn 0.975 Fe 0.975 P 0.5 Si 0.5 alloy are employed to tune the magnetocaloric properties. The results provide insights and systematic understanding into the effect of quenching temperature on the magnetocaloric properties of (Mn,Fe) 2 (P,Si)-based alloys.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 24
·10922-10941
·
IF 3.553
Yang Bin,Ding Mengya,Wu Jinbao,Chen Qinting,Zhao Hongliang,Yu Yangnan,Pan Yang,Qian Jiasheng,Miao Jibin,Tu Youlei,Shi You
In this study, a series of polyethylene thin films were prepared by thermally induced phase separation (TIPS) method with di(2-ethylhexyl)phthalate as the diluent. Morphological observations showed that the microstructures at different locations were fairly distinct and could generally be divided into three layers. When the polymer concentration was lower than the monotectic point (Φ m ), both pore size and porosity in TIPS films were heavily determined by growth time and growth rate of the diluent droplets. At relatively higher polymer concentration, cooling rate heavily affected the pore size in the films primarily through its influence on polymers’ crystallization process. The relationship between the film microstructure and cooling rate was quantitatively investigated (especially the effect of quenching conditions on the evolution of film morphology) with the aid of an enthalpy transformation method, which established the three-dimensional temperature profiles and supplied an insight into the competition between phase separation kinetics and polymer crystallization. In addition, our findings showed that the pore size, porosity and thermal stability of films all increased with an increasing quenching temperature, which was significantly different from the trends of variation in water vapor transmission rate as well as the \( E^{\prime}_{ \hbox{max} } \) and \( E^{\prime\prime}_{ \hbox{max} } \) values of dynamic mechanical analysis as the quenching temperature increased. The present work presents a facile way of in situ tailoring hierarchical microstructures in TIPS films of crystalline polymers, which will be very useful to the design of polymer porous films with specific properties.
研究领域:
材料科学
·
高分子工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 59
·期 5
·412-427
·
IF 0
Bin Yang,Qinting Chen,Mengya Ding,Yang Pan,Peng Zhang,Shuqing Wang,Jiasheng Qian,Jibin Miao,Ru Xia,Peng Chen,You Shi,Youlei Tu
Polyvinylidene fluoride (PVDF) films were prepared via thermally induced phase separation (TIPS) using diphenyl carbonate as the diluter in an attempt to disclose the competitive relationship between crystal growth and droplet growth during phase separation process. By varying the quenching temperature different temperature gradient fields were established, which were theoretically evaluated via enthalpy transformation method. The effects of polymer concentration and quenching temperature on evolution of hierarchical morphologies in TIPS films were systematically investigated. According to the morphological characteristics, the cross-sectional morphology of the films with lower polymer concentration ( Φ P = 25%) could be divided into three layers; while that of higher polymer concentration counterpart ( Φ P = 55%) only presented a bi-layered structure. The reason for this could be ascribed to the effect of cooling rate on both crystal growth and droplet growth during TIPS process, which further determined the formation of the hierarchical structure in microporous films. With an increasing quenching temperature, both pore size and porosity of PVDF films increased, accompanied by an improvement on both thermal stability and dynamic mechanical thermal property. The present study could insightfully supply a facile route to fabricate structure-controllable microporous films of crystalline polymers via an appropriate regulation of the TIPS quenching parameters. Graphical Based upon the phase diagram of polyvinylidene fluoride (PVDF)/diphenyl carbonate (DPC) system, the effects of polymer concentration and quenching temperature on the morphologies in thermally induced phase separation (TIPS) films are quantitatively established. TIPS films with lower (below monotectic point) and higher (above monotectic point) polymer concentrations present three-layered and bi-layered hierarchical structures, respectively, primarily originating from the competition between crystal growth and droplet growth during the phase separation.
研究领域:
材料科学
·
高分子工程
·
化学工程
✓ 已验证
产品关联
DOI
Applied Water Science
·
2022
·Vol. 12
·期 3
·1-11
·
IF 5.411
He Ting,Li Xiaogang,Wang Qian,Zhou Yue,Wang Xiaozu,Wang Zhaohui,Tavajohi Naser,Cui Zhaoliang
In this paper, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate was the first time successfully utilized as single solvent in preparing the PVDF membrane with a good performance by N-TIPs method. The effects of quenching temperature and hydrophilic additive content on the morphology, permeability, and strength of the membranes were studied. All the prepared PVDF membranes were proved to be a pure β phase by FTIR and XRD, possessing a narrow pore size distribution. By adjusting quenching temperature and additive content, membranes with a flux of 383.2 L/m 2 h and concentrated pore diameter of 26 nm obtained.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 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）