POLYMER INTERNATIONAL
·
2018
·Vol. 67
·期 9
·1221-1228
·
IF 2.352
Meng Ma,Kai Liu,Haiming Zheng,Si Chen,Bozhen Wu,Yanqin Shi,Xu Wang
Poly( l -lactic acid)/crosslinked polyurethane (PLLA/CPU) blends which were prepared via reactive blending of PLLA with poly( ϵ -caprolactone) (PCL), glycerol and 4,4′-methylenediphenyl diisocyanate showed excellent toughness. The effects of the composition of the mixture and degree of crosslinking of CPU on the toughness of the PLLA/CPU blends (80/20 w/w) were studied in detail. Dynamic mechanical analysis and rheological measurements were used to characterize the structure of the in situ formed CPU in the PLLA matrix. A novel netlike phase structure was observed when the average molecular weight of PCL and degree of crosslinking were 1 kDa and 10%, respectively. The impact strength of the blend was enhanced from 2.2 kJ m −2 for pure PLLA to 62.4 kJ m −2 ; meanwhile, the elongation at break was increased to 489.8%. Therefore, the mechanical properties of PLLA/CPU blends can be easily tailored by tuning the composition of the mixture and the degree of crosslinking of CPU. © 2018 Society of Chemical Industry
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2020
·Vol. 10
·期 5
·367
·
IF 2.404
Xiaoyi Gao,Nannan Dong,Fangquan Xia,Qinghu Guo,Hua Hao,Hanxing Liu,Shujun Zhang
The impact of phase structure on piezoelectric performances of <001> textured Na0.5Bi0.5TiO3(NBT) based lead-free ceramics was studied, including 0.88NBT-0.08K0.5Bi0.5TiO3-0.04BaTiO3(88NBT) with morphotropic phase boundary (MPB) composition and 0.90NBT-0.07K0.5Bi0.5TiO3-0.03BaTiO3(90NBT) with rhombohedral phase. Both textured ceramics exhibit a high Lotgering factor, being on the order of f~96%. The piezoelectric coefficients of the textured 88NBT and 90NBT ceramics are increased by 20% and 60%, respectively, comparing to their randomly oriented ceramics. The piezoelectric enhancement of 90NBT textured ceramic is three times higher than 88NBT, revealing the phase structure plays a significant role in enhancing the piezoelectric performances of textured ceramics. Of particular significance is that the 90NBT textured ceramic exhibits almost hysteresis-free strain behavior. The enhanced piezoelectric property with minimal strain hysteresis is attributed to the <001> poled rhombohedral engineered domain configuration.Keywords:textured ceramics;phase structure;rayleigh analysis;strain behavior
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 26
·20981-20991
·
IF 2.779
Yan Gui-wei,Liu Qing-qing,Fang Bi-jun,Chen Zhi-hui
Mg doped (Ba 0.98 Li 0.02 )TiO 3 energy storage ceramics with antiferroelectric-like double hysteresis loops were prepared using solid-state reaction method. XRD patterns indicated that tetragonal phase structure of the pure (Ba 0.98 Li 0.02 )TiO 3 ceramic was destroyed and the orthorhombic phase structure appeared with Mg doping. The ratio of orthorhombic/tetragonal phase increased with Mg content increasing, and the value of polarization was in direct proportion to the ratio of orthorhombic/tetragonal phase. The breakdown strength of (Ba 0.98 Li 0.02 )(Mg x Ti 1− x )O 3 ceramics was improved from 60.97 kV/cm at x = 0 to 103.66 kV/cm at x = 0.04. The optimum energy storage properties of (Ba 0.98 Li 0.02 )(Mg x Ti 1− x )O 3 ceramics were obtained with energy storage density of 0.76 J/cm 3 at 102.5 kV/cm when x = 0.04, which is nearly 2.3 times larger than the pure (Ba 0.98 Li 0.02 )TiO 3 ceramic, and the energy storage efficiency was improved from 64 to 87%.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 12
·9167-9175
·
IF 2.22
Cai Wei,Zhang Qianwei,Zhou Chuang,Gao Rongli,Zhang Shilong,Li Zhendong,Xu Ruicheng,Chen Gang,Deng Xiaoling,Wang Zhenhua,Fu Chunlin
Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O 3 (BCZT) ceramics with various grain sizes were fabricated through solid-state method followed by different sintering temperatures. The influences of grain size and phase structure on the electric properties and energy storage performance were systematically investigated. The remnant polarization and quasi-static piezoelectric constant of BCZT samples increase gradually as grain size increases, and the samples with the grain size of 44.37 µm exhibit excellent ferroelectricity and piezoelectricity (2 P r = 25.4 µC/cm 2 , d 33 = 513 pC/N). Although the energy storage density of BCZT samples with the grain size of 8.28–44.37 µm is relative lower, all the ceramic samples have higher energy storage efficiency (82–87.4%). There is the maximum energy storage density in phase transition temperature of tetragonal–cubic phase for all BCZT ceramics and the maximum energy storage density first increases and then decreases with the increase of grain size. But the energy storage density of BCZT ceramics near room temperature decreases with increasing of grain size. The smaller grain size is beneficial to improve the room temperature energy storage density of BCZT samples and is disadvantageous to obtaining superior ferroelectric and piezoelectric properties.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2012
·
IF 1.751
Lin Gan,Zhi-Yong Mao,Yu-Qiang Zhang,Fang-Fang Xu,Ying-Chun Zhu,Xue-Jian Liu
Ce 3+ -doped β-SiAlON blue phosphors with composition of Ce x Si 6− z Al z O z N 8− z (0.2≤ z ≤4) at a fixed x =0.01 were synthesized by the gas pressure sintering method. The phases and photoluminescence properties were found to be directly correlated to the z value. Higher z value would result in the formation of AlN polytypoid impurity phases. The optimal z value resides in the range 0.3≤ z ≤0.5, by which high purity of β-SiAlON phase, good crystallinity and fine grain size were obtained, leading to the best luminescence properties. These phosphors could be a good candidate for application in white light-emitting diodes using InGaN-based near–ultraviolet chips.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Corrosion Communications
·
2023
·
IF 0
Xiaoping Lai,Jie Wang,Xin Wang,Kuo Jiang,Weizhi Tian,Baowen Xu
YSZ:Eu powder was prepared by sol spray pyrolysis method. Thermal barrier coatings (TBCs) composed of Eu 3+ -doped pure tetragonal yttrium-stabilized zirconia (namely, YSZ:Eu) were fabricated by air-plasma spraying technique. Crystal structure and fluorescence intensity of YSZ:Eu coating were investigated after aging at 1200 °C for 5 − 100 h. X-ray diffraction (XRD) indicates that tetragonal phase in YSZ:Eu coating had high resistance to degradation over a wide range of time periods and temperatures. Luminescence results indicate that asymmetry ratios of the fluorescence emission spectra were stable in a range of 1.2 ± 0.2. Relationships between phase structure and lattice distortion were further studied by fluorescence spectroscopy measurement using I 606 / I 590 intensity ratio. The fluorescence results were consistent with those drawn by XRD, where the high stability of YSZ:Eu coating was confirmed. Excellent thermal stability, in terms of both the phase structure and luminescence intensity, of YSZ:Eu coating indicates that the present preparation method is suitable for phosphor powder applications.
研究领域:
材料科学
·
无机化学
·
光学
✓ 已验证
DOI
CONSTRUCTION AND BUILDING MATERIALS
·
2018
·
IF 3.485
Xiaohui Sheng,Mo Wang,Tao Xu,Jun Chen
To prepare new polyurethane (PU) modified emulsified asphalt (EA), and further understand modification mechanism of PU to EA, effects of PU on basic engineering performances, chemical composition compatibility, morphology and element compositions, thermal properties, phase microstructures of EA were discussed. The results indicate that basic properties of PU modified EA firstly meet relevant requirements of technical specifications. Improvement effects of PU with a suitable content on penetration and ductility is better than that of styrene butadiene styrene (SBS), but their softening points are similar. Secondly, PU modified EA process includes physical and chemical modifications. PU is dispersed uniformly in evaporation residues of EA when PU content is less than 6%, and meta-stable two-phase interface transition layers are formed between PU and asphalt binder, forming a uniform dispersion system and interpenetrating network structures in modified EA. The compatibility between PU and EA is satisfactory, forming a stable multiphase structure in modified EA. This is conductive to improve high-temperature stability and low-temperature ductility of modified EA. Thirdly, the contents of such main chemical elements as carbon (C), oxygen (O) and sulfur (S) in evaporation residues of EA show no obvious changes before and after modified by PU, indicating that physical modification is main method during the preparation of PU modified EA. Fourthly, PU is difficult to form a continuous crystalline phase in EA. However, the molecular chain spacing and microcrystalline size of PU modified EA are decreased at a suitable PU content, generating more compact interpenetrating network of molecular chains. Motions of asphalt molecules are limited, improving thermal stability and mechanical properties of EA. Finally, a suitable PU content of 6% is proposed to prepare modified EA.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Zhuangzhi Wu,Rongbin Zhang,Hao Fei,Ruoqi Liu,Dezhi Wang,Xinli Liu
The NH 3 is generally synthesized by the traditional Haber–Bosch method, which is energy-consuming and releases a lot of CO 2 . Electrocatalytic fixation of N 2 is highlighted as a carbon-free route to generate NH 3 by the nitrogen reduction reaction (NRR), but strongly demands highly efficient and durable electrocatalysts. Herein, we propose the multiphasic 1T@2H-MoSe 2 as a highly active NRR catalyst for the first time, which exhibits excellent activity for the NRR with a NH 3 yield of 19.91 ± 0.89 μg h −1 mg cat . −1 and a FE of 2.82% ± 0.1% at −0.6 V in 0.1 M Na 2 SO 4 . Moreover, a good durability is also demonstrated.
研究领域:
材料科学
·
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Yun-Long Mu,Qing He,Chun-Yan Li,Da Sheng,Song-Hai Wu,Yong Liu,Hai-Tao Ren,Xu Han
Although precise regulation of the crystalline structures of metal oxides is an effective method to improve their antibacterial activities, the corresponding mechanisms involved in this process are still unclear. In this study, three kinds of cuprous oxide (Cu2O) samples with different structures of cubes, octahedra, and rhombic dodecahedra (c-Cu2O, o-Cu2O, and r-Cu2O) have been successfully synthesized and their antibacterial activities are compared. The antibacterial activities follow the order of r-Cu2O > o-Cu2O > c-Cu2O, revealing the significant dependence of the antibacterial activities on the crystalline structures of Cu2O. Quenching experiments, as well as the NBT and DPD experiments indicate that ≡CuII─OO• superoxo and ≡CuII─OOH peroxo, instead of •OH, O2•–, and H2O2, are the primary oxidizing species in the oxidative damage to E. coli. Raman analysis further confirms the presence of both ≡CuII─OO• superoxo and ≡CuII─OOH peroxo on the surface of r-Cu2O. On the other hand, the NCP experiment reveals that Cu+, instead of Cu2+, also contributes to the antibacterial process. This study provides new insight into the antibacterial mechanisms of Cu2O.
研究领域:
材料科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2025
·Vol. 15
·期 11
·806
·
IF 4.3
Xiaojiao Yang,Shuai Han,Hongna Xing,Yi Dong,Xia Deng,Yan Zong,Juan Feng,Xiuhong Zhu,Xinghua Li,Xinliang Zheng
MOFs-derived magnetic carbon-based composites are considered to be valuable materials for the design of high-performance microwave absorbents. Regulating phase structures and introducing mixed-valence states within the composites is a promising strategy to enhance their charge transfer properties, resulting in improved microwave absorption performance. In this study, iron oxide components show a temperature-dependent phase evolution process (α-Fe 2 O 3 →Fe 3 O 4 →Fe 3 O 4 /FeO), during which the valence states of iron ions are regulated. The tunable phases modulate the magnetic Fe 3 O 4 component, resulting in enhanced magnetic loss. The changed valence states affect the polarization relaxation by adjusting the electronic structure and tune the electron scattering by introducing defects, leading to enhanced dielectric loss. The microwave absorption properties of iron oxide@carbon composites display phase- and valence state-dependent characteristics. Especially, Fe 3 O 4 @C composites exhibit superior microwave absorption properties, ascribed to the improved magnetic/dielectric losses induced by good impedance matching and strong microwave attenuation capacity. The minimum reflection loss of Fe 3 O 4 @C composites reaches −73.14 dB at 10.35 GHz with an effective absorption bandwidth of 4.9 GHz (7.69–12.59 GHz) when the absorber thickness is 2.31 mm. This work provides new insights into the adjustment of electromagnetic parameters and microwave absorption properties by regulating the phase and valence state.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2014
·
IF 2.291
Xingyuan Guo,Changfeng Chen,Shengyan Yin,Weiye Song,Feng Shi,Weiping Qin.
In this work, the effects of NaYF 4 :Yb 3+ , Tm 3+ (NYT) structure on the near-infrared light (NIR) photocatalysis performance of ZnO were investigated. α-NYT/ZnO nanocomposites (NCs) and β-NYT/ZnO NCs were fabricated by a high temperature decomposition reaction method. The prepared NCs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, Raman spectroscopy, and photoluminescence spectra (PL). The NIR photocatalytic activities of the synthesized α- and β-NYT/ZnO NCs were studied by the degradation of Rhodamine B. The differential photocatalytic activities between of α- and β-NYT/ZnO NCs are believed to be correlated to the effects of α- and β-NYT on the oxygen vacancies and exposed crystal face of ZnO.
研究领域:
材料科学
·
光催化
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xiankun Wu,Jiale Zhang,Haonan Li,Huihui Gao,Mang Wu,Zhongkai Wang,Zhong Wang
It is a key challenge to combine high mechanical strength and excellent autonomous self-healing properties in one elastomer to match the requirements of commercial applications. Chemical cross-linking or ordered crystalline domains can afford high mechanical strength but are often based on the cost of losing autonomous self-healing performance. To address this dilemma, a strategy involving dual hard-phase structures was developed to reinforce self-healing polyurethane elastomers, by introducing plant oil-derived aliphatic chains into the hard segments. The dangling fatty acids not only allow segmental motion of the hard domains but also suppress the crystallization within polyurethane soft segments. The tailored dual-hard phase structure and dynamic chain motion are responsible for outstanding mechanical properties (tensile strength to 21.8 MPa and toughness of 131.6 MJ m −3 ) and autonomous self-healing ability (∼100 % healing efficiency). Furthermore, a versatile mechanical robust flexible conductor is conveniently constructed with an auto-repair capability at ambient conditions. This work represents a molecular design paradigm of simultaneously integrating balanced mechanical strength, durability, and self-healing ability for high-performance elastomers that can find applications such as skin-inspired wearable devices.
研究领域:
材料科学
·
化学工程
✓ 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）