JOURNAL OF APPLIED POLYMER SCIENCE
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2025
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IF 2.8
Hongbao Wang,Zonglin Yi,Hao Liu,Zhenbo Zhao,Shouchun Zhang,Quangui Guo,Fangyuan Su,Xinghua Zhang
The boric acid modification offers an effective approach to improve the radial homogeneity and mechanical performance of polyacrylonitrile (PAN)-based carbon fibers by affecting stabilization behavior. However, the mechanism of how boron affects the stabilization process remains unclear. Herein, the impact of boron on the cyclization and oxidation reactions is investigated through experimental data and computational calculations. The results reveal that boron oxide exhibits a stronger electron-withdrawing effect on cyano nitrogen compared to hydroxyl oxygen, effectively inhibiting both ionic and free radical cyclization reactions, as well as subsequent oxidation reactions in the skin regions. This inhibitory effect enhances the cross-sectional oxygen uptake and stabilization. The boric acid also improves the preferred orientation in precursor fibers by reducing the polarity of cyano groups and promotes the inheritance of structural characteristics from precursor fibers through “cross-linking” effect. Consequently, the structural characteristics and mechanical properties of modified carbon fibers are significantly improved. These findings could provide fundamental insights into the mechanisms of thermal reaction regulation and microstructure evolution in the preparation of high-performance PAN-based carbon fibers.
研究领域:
材料科学
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高分子科学
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化学工程
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纳米技术
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机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Chongyang Chen,Benshuang Sun,Bingxue Han,Lijia Chen,Bin Wu,Chengduo Wang,Zhijun Wang
Indium zinc oxide (IZO) ceramic targets have been extensively studied due to the advantage of high film mobility and controllable resistivity. As the base materials used for IZO ceramic targets, it is crucial to synthesize IZO composite nanoparticles by an effective technique. Herein, praseodymium (Pr)-doped IZO composite nanoparticles are fabricated by co-precipitation method. The influencing factors for the synthesis of the composite nanoparticles are analyzed, and the nanoparticles show the best properties of most uniform particle shape, size, and elemental distribution under the preparation conditions of ammonia or sodium hydroxide as an alkaline precipitant, pH of 7, and sintering temperature of 800°C. The phase composition, micro-morphology, compositional homogeneity, and chemical bonding and functional group changes of precursors and sintered particles are analyzed. Meanwhile, combined with the thermogravimetric - differential scanning calorimetry (TG-DSC) analysis of the decomposition process of the hydroxide precursor during heating, the crystallization activation energy for the transformation of the precursor from the amorphous to the crystalline state was calculated by the Kissinger and Ozawa method. Based on the concept of crystallization fraction, the crystallization mechanism of the mixed particles of precursors is explored. In addition, ceramic targets prepared from the IZO nanoparticles by this method exhibit excellent uniform elemental distribution and fine grain (<4 µm), high density (>99%), and low resistivity (<4 mΩ·cm). This work provides an efficient strategy for the preparation of IZO composite nanoparticles for applications in advanced photoelectric ceramic targets.
研究领域:
材料科学
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纳米技术
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陶瓷材料
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光电子学
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2023
·
IF 4.6
Mei-Juan Xie,Chang-Cheng Wang,Rong Zhang,Jian Cao,Mao-Zhu Tang,Yun-Xiang Xu
Inhomogeneous network construction is a useful strategy to solve the trade-off between mechanical strength and creep in vitrimer rubbers. But it is still lack of tools to tune the mechanical properties and network dynamics of this new system. In this paper, uneven distribution of functional groups was realized by sequential coordination polymerization of myrcene and isoprene and epoxidation . The following epoxidation and curing generated VMI-x samples with inhomogeneous network. Polyisoprene was used to prepare control samples called VPI-x with homogeneous network. Different lengths of dicarboxylic acid crosslinkers (SA = succinic acid, HA = heptanedioic acid, DA = decanedioic acid) were used to probe their effects on dynamic behaviors, mechanical properties and recyclability . Morphological test and nanomechanical mapping confirmed the inhomogeneous feature of VMI-x samples. For both inhomogeneous and homogeneous samples, SA and DA crosslinkers brought higher tensile strength and modulus, earlier SIC phenomenon and higher orientation percentage of amorphous molecular chains than those of HA, which are ascribed to extra permanent cross-linking existing in SA samples and transition entanglements existing in DA samples. However, the constrain effect of SA crosslinker is too strong in inhomogeneous network to sacrifice the extensibility, which is much smaller than those of HA and DA. SA and DA samples also present restricted segmental motion and superior creep resistant properties compared to HA samples according to the results of broadband dielectric spectroscopy and DMA test. Differently, at high temperature above 130 °C, the stress relaxation, topology freezing transition temperature (Tv) and recycling efficiency of strength are dominated by the crosslinker length monotonically, probably due to the disentanglement of DA crosslinkers. Compared to homogeneous network, inhomogeneous ones showed obvious enhanced mechanical properties, lower hysteresis, quicker segmental relaxation, lower creep and quicker network relaxation. This work demonstrates that crosslinker lengths could tune the vast aspects of vitrimer elastomers and is a non-negligible factor to determine their properties, especially for those with inhomogeneous networks.
研究领域:
高分子科学
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材料工程
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软物质物理
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化学合成
✓ 已验证
DOI
高影响因子
Biofabrication
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2023
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IF 9
Jianpei Dong,Jianhua Zhou,Hao Tang,Baiqi Chen,Lu Huang
Cell-laden hydrogel microstructures have been used in broad applications in tissue engineering, translational medicine, and cell-based assays for pharmaceutical research. However, the construction of cell-laden hydrogel microstructures in vitro remains challenging. The technologies permitting generation of multicellular structures with different cellular compositions and spatial distributions are needed. Herein, we propose a laser-guided programmable hydrogel-microstructures-construction platform, allowing controllable and heterogeneous assembly of multiple cellular spheroids into spatially organized multicellular structures with good bioactivity. And the cell-laden hydrogel microstructures could be further leveraged for in vitro drug evaluation. We demonstrate that cells within hydrogels exhibit significantly higher half-maximal inhibitory concentration values against doxorubicin (DOX) compared with traditional 2D plate culture. Moreover, we reveal the differences in drug responses between heterogeneous and homogeneous cell-laden hydrogel microstructures, providing valuable insight into in vitro drug evaluation.
研究领域:
组织工程
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转化医学
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药物研究
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生物技术
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细胞生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2025
·
IF 16
Liang Chen,Yuming Zhang,He Qi,Ruiyu Wang,Yunxuan Ji,Takumi Nishikubo,Masaki Azuma,Chang Zhou,Jun Chen
The significant polarization hysteresis under external fields can be stimulated by long-range ordered distortions, including cation displacements and oxygen octahedral tilts, deteriorating the energy storage performance and reliable operation of dielectric capacitors. Here, we propose a strategy of localized distortion to craft a disordered nanostructure landscape, manifested as strongly polar orthorhombic rocks dissociated in the transition region of polymorphic nanoclusters and strong oxygen-tilted blocks embedded in the weak oxygen distortion region, resulting in a smooth polarization response trajectory with large polarization fluctuations, small hysteresis, and delayed polarization saturation. Through localizing distortion, an ultrahigh recoverable energy density of 12.5 J cm–3 can be realized with an inspiring efficiency of 87%, alongside ultrawide capacitance temperature stability (from −100 to 432 °C) far exceeding X9R criteria, showing breakthrough progress in the overall performance for NaNbO3-based lead-free bulk ceramics. This work unveils an effective avenue of localized distortion to develop dielectrics with excellent energy storage performance and the potential to be extended to other functionalities.
研究领域:
材料科学
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介电与电磁材料
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能量存储
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铁电材料
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陶瓷
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）