Nanoscale
·
2024
·
IF 5.8
Xiaodong Yu,Jihao Fan,Shengquan Zheng,Linlin Ma,Xiaojing Liu,Yue Wu,Chuangqi Zhao,Lei Jiang
High strength/toughness nanocomposites are increasingly in demand due to the development needs of high-end applications. However, the aggregation and random orientation of nanofillers and the weak crosslinking of the polymer matrix lead to the degradation of the mechanical properties of nanocomposites. Here, we present a strategy to prepare chitosan-based nanocomposites with aligned nanosheets via the in situ photo-crosslinking of modified chitosan. The well-dispersed and highly aligned nanosheets, as well as the dense covalently crosslinked network between the modified chitosan chains, effectively improve the mechanical properties of the prepared nanocomposites. For example, the chitosan-based nanocomposite films exhibit a tensile strength of up to 340.6 ± 13.4 MPa, a Young's modulus of 8.2 ± 0.2 GPa and a toughness of 22.0 ± 2.5 MJ m−3, which are 4.2, 4.8 and 1.8 times higher, respectively, than those of pure chitosan films. Moreover, the thermal decomposition temperature of the chitosan-based nanocomposite films reaches 286.8 °C, which is 48.5 °C higher than that of pure chitosan films. We consider that our strategy, which constructs a crosslinked chitosan structure with aligned nanofillers, could lead to the development and application of the bio-based composites with excellent mechanical properties.
研究领域:
材料科学
·
生物工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COMBUSTION AND FLAME
·
2023
·
IF 4.4
Erhai An,Yihong Tan,Kehua Han,Xiaoxia Li,Xiong Cao,Yingxin Tan,Peng Deng
Molecular perovskite energetic material DAP-4 is seen as a potential high-energy oxidant due to its high energy, high density, high oxidation capacity, and facile preparation technology. However, optimizing its energy release and reducing its thermal decomposition temperature are huge challenges for its future application. In this work, the role of iron (Fe) nanospheres in the energy release of DAP-4 was studied. Our research has shown that Fe powder can not only serve as a fuel to promote combustion, but also as an important catalyst to significantly improve the thermal decomposition, energy release, and burning rate of DAP-4. By adding 25% Fe nanospheres, the decomposition temperature of DAP-4 was reduced to 299.7 °C, which is the most reduction by 84.7 °C from 384.4 °C (raw DAP-4) to 299.7 °C (DAP-4/Fe-5 with 25wt% Fe nanospheres) was obtained. The decomposition activation energy also decreases by at least 69.5 kJ mol −1 from 229.4 kJ mol −1 (DAP-4) to 159.9 kJ mol −1 (DAP-4/Fe-1 with 5wt% Fe nanospheres). The combustion performance of DAP-4/Fe composites is significantly improved by a 4∼5 times shorter burn rate. The energy-releasing mechanism of DAP-4 with the presence of Fe nanospheres was proposed. Fe x O y at the surface of Fe nanospheres played an important role in the energy releasing of DAP-4. This work showed a new idea for the potential application of molecular perovskite energetic materials.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
Defence Technology
·
2021
·
IF 3.172
Song Zhang,Le-wu Zhan,Guang-kai Zhu,Yi-yi Teng,Yu Shan,Jing Hou,Li Bin-dong
Nano-TATB was developed in microchannels by physical method and chemical method, respectively. The effects of total flow rate, number of microreactor plates, solvent/non-solvent ratio and temperature on the particle size of TATB in the physical method were studied. Prepared TATB were characterized by Nano Sizer, Scanning Electron Microscopy, Specific surface aperture analyzer, X-ray diffraction, Fourier transform infrared spectroscopy and Differential Scanning Calorimetry. The results show that the TATB obtained by physical method and chemical method are spherical, with average particle size of 130.66 nm and 108.51 nm, respectively. Specific surface areas of TATB obtained by physical and chemical methods are 21.37 m 2 /g and 21.91 m 2 /g, respectively. Compared with the specific surface area of micro-TATB (0.0808 m 2 /g), the specific surface area of nano-TATB is significantly increased. DSC test results show that the smaller the particle size of TATB, the lower the thermal decomposition temperature. In addition, by simulating the mixing state of fluid in microchannels and combining with the classical nucleation theory, the mechanism of preparing nano-TATB by microchannels was proposed.
研究领域:
材料科学
·
化学工程
·
爆炸物研究
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2024
·
IF 9.6
Ning Hui-Long,Liang Chao-Ping,Qiang Shan-Shan,Li Jie-Xiang,Tang Sheng,Li Ye-Tao,Sun Wei,Yang Yue
Iron disulfide (FeS 2 ) has been widely used in thermal batteries because of its high theoretical specific capacity and voltage plateau. However, low thermal decomposition temperature, poor conductivity and inferior actual specific capacity limit its wide applications. Herein, we report a gold-doped FeS 2 (FeS 2 -Au), which not only reduces the band gap of the FeS 2 crystals but also enriches the electron transport path of FeS 2 by the formation of Au nanoparticles. First-principles calculation shows that the diffusion energy barrier of lithium-ion is reduced after the Au-doped FeS 2 . In addition, Au increases the electron cloud density around sulfur atoms, which helps to enhance the stability of Fe-S covalent bonds and thus results in better thermal stability of FeS 2 . When the Au content is 130 μg·g −1 (FeS 2 -Au 4 ), the thermal decomposition temperature (TG 5% ) of FeS 2 -Au is 72.2 °C higher than that of pristine FeS 2 . At a discharge temperature of 500 °C, a current density of 200 mA·cm −2 and a cutoff voltage of 1.4 V, FeS 2 -Au 4 demonstrates superior specific capacity and high specific energy compared to FeS 2 . More precisely, the specific capacity of FeS 2 -Au 4 attains a value of 379 mAh·g −1 , with a corresponding specific energy of 714 Wh·kg −1 . In contrast, the discharge specific capacity and specific energy of FeS 2 are lower, amounting to 348 mAh·g −1 and 656 Wh·kg −1 , respectively. This study offers a novel approach to enhancing the electrochemical performance of FeS 2 in high-temperature molten salt electrochemical systems (thermal batteries), thereby laying a solid foundation for its potential practical application. Graphic abstract
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Kuichen Li,Yue Xu,Zehao Jin,Lili Wang
To achieve large-scale commercialized use of white quantum dots light-emitting diodes (WQLEDs). It is vital to find environmentally friendly and inexpensive luminescent materials without rare earth participation. In this paper, the zinc sulfide quantum dots with different Cu 2+ contents (ZnS:Cu-QDs) were prepared by one-step hydrothermal method , the quantum yield can reach 27.65 % and the thermal decomposition temperature is 610 ℃. Furthermore, the luminescence mechanism of ZnS:Cu-QDs was explored. The wavelength-tunable WQLEDs were fabricated. The WQLEDs exhibit from standard white light to warm white light with a relative colour temperature in the range of 4764–3851 K. The as-prepared WQLEDs from ZnS:Cu0.8 %-QDs show a warm white light with International Commission on Illumination (CIE) coordinates of (0.4009, 0.4265), colour rendering index (CRI) of 72.1, and the correlated colour temperature (CCT) of 3851 K at an input voltage of 3.4 V. This research provides a promising way for achieving WQLEDs by single phase quantum dots without the addition of rare-earth elements.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
TRIBOLOGY INTERNATIONAL
·
2023
·
IF 6.2
Simei Peng,Linyuan Luo,Renzhao Wu,Zhuwu Yi,Yishun Wuliu,Pu Shi,Jin Zhu,Jianxiang Feng,Yuejun Liu
We demonstrated an innovative strategy to synthesize a biobased multifunctional anti-scratch agent (BCP) based on biomass cardanol, and its properties impact for polypropylene (PP) was investigated. The scratch behavior analyses show that incorporation of BCP tremendously ameliorates scratch visibility, greatly decreases scratch depth, color difference and kinetic friction coefficient for PP, which owing to the lubricating layer induced by BCP migration onto the polymer surface . Meanwhile, the addition of BCP greatly increases the initial thermal decomposition temperature of PP and improves the impact strength , mainly benefitting from BCP intramolecular synergism. Furthermore, the constituting concept of novel green BEP enriches the design of polymer additives , with potential expansion into other biomass functionalization with multifunctional variations.
研究领域:
材料科学
·
生物基材料
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE AND ENGINEERING OF COMPOSITE MATERIALS
·
2021
·Vol. 28
·期 1
·528-539
·
IF 1.295
Su Xiaofeng,Yu Yitao,Li Bing,Wang Jing,Lu Chuan,Zong Jianping,Li Jinhui,Wang Feng
In order to prepare polyurethane–polysiloxane block copolymers, α,ω-hydroxyalkyl polysiloxanes with methacrylate side chain and α,ω-bis(2-methyl-3-hydroxypropyl)polymethyl(2-methyl-methylpropanoate) siloxanes, were synthesized and characterized in this study. The syntheses process included hydroxyl protection, hydrosilylation, deprotection, and ring-opening equilibrium reactions. The intermediates and target products were characterized by Fourier transform infrared spectroscopy and 1 H nuclear magnetic resonance methods. The characterization results showed that each step was successfully carried out in all the cases. Then the waterborne polyurethane–polysiloxane block copolymers were prepared via step-growth polymerization. The properties of the block copolymer films were characterized by thermal gravimetric analysis, differential scanning calorimetry, and dynamic thermomechanical analysis methods in detail. The experimental results showed that the block introduction of hydroxyalkyl polysiloxane could reduce the water absorption of waterborne polyurethane from 62 to 11%, and significantly improve the water resistance of polyurethane. With the introduction of polysiloxane, the tensile strength decreased and the elongation at break increased. At the same time, with the increase of the polysiloxane content, the glass transition temperature of the soft segment decreased to −56.4°C and the thermal decomposition temperature increased to 300°C. The results revealed that the introduction of polysiloxane could effectively improve the comprehensive performance of polyurethane–polysiloxane block copolymer films.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2021
·Vol. 28
·期 7
·1-10
·
IF 3.097
Xian Wenqi,Yuan Jie,Xie Zhengbin,Ou Wei,Liu Xiaoxuan,Liu Baohua
A series of CO 2 copolymer-based waterborne polyurethanes with high solid content were successfully prepared by using CO 2 copolymer diol, isophorone diisocyanate, and dimethylol propionic acid as the donors of hydrophilic groups. In order to obtain of the emulsion with high solid content and good physical property, the synthesis conditions of CO 2 copolymer-based waterborne polyurethane were studied. The influence of dimethylol propionic acid content and synthesis process on the physical property of the emulsion was also investigated. Results show that CO 2 copolymer-based waterborne polyurethane with high solid content can be synthesized by chain expansion at relatively low temperature. The waterborne polyurethane emulsion particle size distribution was wide. As the content of hydrophilic groups in prepolymer increased, the viscosity and water absorption increased obviously, this is difficult to synthesize waterborne polyurethane with high solid content and low water absorption. Thermal gravimetric analysis shows that the higher the chain extending temperature of CO 2 copolymer-based waterborne polyurethane, the higher the thermal decomposition temperature. When the CO 2 molar content of CO 2 copolymer diol is about 30%, the CO 2 copolymer-based waterborne polyurethane has high strength and better water resistance.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2017
·Vol. 75
·期 5
·2181-2196
·
IF 1.43
Chen Tenghui,Li Qiuying,Fu Zhiwei,Sun Lewen,Guo Weihong,Wu Chifei
Crosslinked ultra-high-molecular-weight polyethylene (UHMWPE) with excellent shape memory properties was prepared from the silane-grafted UHMWPE mixed with water-carrying agent by compression molding. The alkoxysilane hydrolyzation and condensation reaction of the silane-grafted UHMWPE allowed for the generation of Si–O–Si chemical crosslinking points between the polymeric chains. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results confirmed that silane has been grafted on UHMWPE chains successfully. The resulting crosslinked products were characterized using dynamic mechanical analysis, gel measurement, impact test, tensile test, thermogravimetric analysis and shape memory bending test to obtain insight into the relationship between the structure and the properties. By controlling the content of water-carrying agent, the average molecular weights between crosslinking points ( M
c ) reduced from 29,530 to 9540 g/mol. The decomposition temperature ( T
d ) value increases from 467.7 for virgin resin to 491.5 °C for the crosslinked product with 91.64% gel ratio. The crosslinked materials showed much better shape memory effect than pure UHMWPE; the shape recovery ratio ( R
ν
) value of silane-induced crosslinked UHMWPE with 1.0 phr water-carrying agent reaches above 98.0% under multiple deformation recovery cycle. Therefore, the silane-induced crosslinking UHMWPE has a great potential in the shape memory material applications.
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
JOURNAL OF APPLIED POLYMER SCIENCE
·
2013
·Vol. 130
·期 4
·2801-2808
·
IF 1.395
Miao Yin,Li Yang,Xiu-yun Li,Han-bing Ma
The fluorinated epoxy resin, 2,2-bisphenol hexafluoropropane diglycidyl ether (DGEBHF) was synthesized through a two-step procedure, and the chemical structure was confirmed by 1 H n uclear magnetic resonance (NMR), 13 C NMR, and Fourier transform infrared (FTIR) spectra. Moreover, DGEBHF was thermally cured with methyl hexahydrophthalic anhydride (MHHPA). The results clearly indicated that the cured DGEBHF/MHHPA exhibited higher glass transition temperature ( T g 147°C) and thermal decomposition temperature at 5% weight loss ( T 5 372°C) than those ( T g 131.2°C; T 5 362°C) of diglycidyl ether of bisphenol A (DGEBA)/MHHPA. In addition, the incorporation of bis-trifluoromethyl groups led to enhanced dielectric properties with lower dielectric constant ( D k 2.93) of DGEBHF/MHHPA compared with cured DGEBA resins ( D k 3.25). The cured fluorinated epoxy resin also gave lower water absorption measured in two methods relative to its nonfluorinated counterparts. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2801–2808, 2013
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
Nanoscale Advances
·
2019
·Vol. 2
·期 1
·332-339
·
IF 0
Yimin Huang,Li Zhao,Jin Li,Fang Lu,Shimin Wang
Despite being promising photovoltaic materials, widespread use of organic–inorganic halide perovskite materials is still hindered by their undesirable stability. To cope with this challenge, methylamine (MA) is doped into triple cation perovskite single crystals of (FA0.95−xMAxCs0.05)PbI3, and cesium-containing triple cation perovskite single crystals with five different MA molar ratios (x = 0, 0.05, 0.10, 0.15, and 0.20) are synthesized and characterized. Among them, (FA0.8MA0.15Cs0.05)PbI3 shows high stability against water-oxygen and light for 60 days, and the thermal decomposition temperature of (FA0.8MA0.15Cs0.05)PbI3 reaches as high as 305 °C. Besides, the carrier lifetime of (FA0.8MA0.15Cs0.05)PbI3 is up to 5.957 μs, which remains as 5.646 μs (95%) after 60 days of light illumination. This work studies the stability of perovskite single crystals based on (FA0.95−xMAxCs0.05)PbI3 compositions and provides a reference for the discovery of novel perovskite photovoltaic devices with high efficiency and long-term stability.
研究领域:
材料科学
·
光伏技术
·
化学
✓ 已验证
DOI
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2011
·Vol. 212
·期 23
·2589-2593
·
IF 2.437
Hongjun Yang,Manqing Yan,Stergios Pispas,Guangzhao Zhang
Poly[(ethylene carbonate)- co -(ethylene oxide)] is synthesized by ROP of 1,3-dioxolan-2-one using 1- tert -butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2Λ5,Λ5-catenadiphosphazene as the catalyst. NMR spectroscopy shows that the copolymer chain consists of EO-EC-EO-EO sequences. GPC measurements indicate a PDI of 1.43–1.66 and show that the molecular weight increases with monomer conversion. Thermal analysis demonstrates that the copolymer is amorphous with a glass transition temperature of about –42 °C and an onset decomposition temperature of about 200 °C.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）