6 results on '"Chen, Yuxia"'
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2. Aggregation behavior of an amino acid-derived bolaamphiphile and a conventional surfactant mixed system
- Author
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Chen, Yuxia, Liu, Yan, and Guo, Rong
- Subjects
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SURFACE active agents spectra , *CLUSTERING of particles , *AMINO acids , *CHEMICAL systems , *LIGHT scattering , *HYDROGEN bonding , *FOURIER transform infrared spectroscopy - Abstract
Abstract: The aggregation behavior of a mixed system consisting of a novel histidine-derived bolaamphiphile 1,12-dihistidine diaminododecane (H2D) and the conventional surfactant dodecyltrimethylammonium bromide (DTAB) has been investigated. The microstructure of the H2D/DTAB mixture has been identified by means of negative staining-TEM, dynamic light scattering (DLS), fluorescence spectra, FT-Raman spectroscopy, and differential scanning calorimetry (DSC). Rich morphologies are observed in the mixed system of H2D and DTAB over a relatively wide proportion range. At C DTAB/C H2D <12:1, vesicles are formed in the mixed system. At C DTAB/C H2D >12:1, vesicles and tube-like aggregates coexist, and more tube-like aggregates appear with further increase of C DTAB/C H2D. The formation mechanisms of the aggregation with various morphologies at different C DTAB/C H2D ratios are further deduced. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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3. Properties of Luffa Fiber Reinforced PHBV Biodegradable Composites.
- Author
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Guo, Yong, Wang, Li, Chen, Yuxia, Luo, Panpan, and Chen, Tong
- Subjects
PECTINS ,FOURIER transform infrared spectroscopy ,FLEXURAL strength - Abstract
In this study, composites of poly (hydroxybutyrate-co-valerate) (PHBV) with untreated luffa fibers (ULF) and NaOH-H
2 O2 treated luffa fibers (TLF) were prepared by hot press forming. The properties of luffa fibers (LFs) and composites were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and other analysis methods. Results showed that pre-treatment effectively removed pectin, hemicellulose, and lignin, thus reducing the moisture absorptivity of LFs. The flexural strength of TLF/PHBV was higher than that of ULF/PHBV. With 60% LF content, the flexural strengths of ULF/PHBV and TLF/PHBV reached 75.23 MPa and 90.73 MPa, respectively, 219.7% and 285.6% more than that of pure PHBV. Water absorptivities of composites increased with increase in LF content. Water absorptivity of TLF/PHBV was lower than that of ULF/PHBV. The flexural strengths of composites decreased after immersion in water at room temperature. Meanwhile, flexural strength of TLF/PHBV was lower than that of ULF/PHBV. Pretreatment of LFs effectively improved the bonding between fibers and PHBV, resulting in enhanced and thus improved the moisture resistance of composites. [ABSTRACT FROM AUTHOR]- Published
- 2019
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- View/download PDF
4. Preparation and properties of carbon‐fiber‐ and pine‐cone‐fiber‐reinforced high‐density polyethylene composites.
- Author
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Guo, Yong, Liu, Dian, Chen, Yuxia, Zhang, Tingting, and Zhu, Shiliu
- Subjects
CARBON fibers ,POLYETHYLENE ,FOURIER transform infrared spectroscopy ,THERMOGRAVIMETRY ,DIFFERENTIAL scanning calorimetry - Abstract
In this study, we were concerned with the physical properties of carbon‐fiber‐ and pine‐cone‐fiber‐reinforced high‐density polyethylene prepared by compression molding. The resulting composites were characterized by scanning electron microscopy, X‐ray diffraction, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and mechanical testing. The results indicate that the manufacturing properties of the composites were improved with the addition of carbon fibers. The FTIR results showed that the carbon‐fiber reinforcement of the composites was mainly achieved through physical effects. An appropriate content of carbon‐fiber addition improved the interface combination between the fibers and matrix; carbon fibers improve the water absorption of the material, and the relative crystallinity of the composite increased with increasing carbon‐fiber addition. With increasing carbon‐fiber content, the thermal decomposition temperature of the composites increased, and the thermal stability of the composites improved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47304. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
5. Characterization of potential cellulose fiber from Luffa vine: A study on physicochemical and structural properties.
- Author
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Cheng, Dao, Weng, Beibei, Chen, Yuxia, Zhai, Shengcheng, Wang, Chenxin, Xu, Runmin, Guo, Junkui, Lv, Yan, Shi, Lanlan, and Guo, Yong
- Subjects
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CELLULOSE fibers , *THERMOPLASTIC composites , *CELLULOSE nanocrystals , *FOURIER transform infrared spectroscopy , *LIGHTWEIGHT materials , *NATURAL fibers , *COMPOSITE materials - Abstract
The purpose of this study is to investigate the natural Luffa vine (LV) fiber to be effectively used as cellulose fiber reinforcing material for lightweight and decay-resistance composite materials. The physical, chemical, thermal, and morphological properties of the LV fibers, together with their microstructure are investigated. The test results conclude that the LV density, microscopic characteristics, and mechanical properties show that this crop is a lightweight (200–550 kg/m3) natural fiber with a porous structure and a high specific modulus (1.18–2.04 MPa∙ m3/kg). The chemical, X-ray diffraction and the Fourier transform infrared spectroscopy analyses indicate that the LV has a high lignin content (25.18%) and a relatively high relative crystallinity (37.18%) of cellulose, and it contains saponins, which increase its erosion resistance and hardness. The thermogravimetric analysis reveals that the fibers can stand up to 315.4 °C. Moreover, due to their kinetic activation energy of 63.9 kJ/mol, they can be used as reinforcement materials in thermoplastic green composites with a working temperature below 300°. • Luffa vine (LV) have a multi-level porous structure and a high specific modulus. • The presence of saponins help LV develop corrosion-resistant composites. • The LV lignin is mostly guajacyl lignin and only a small amount of syringyl lignin. • The LV thermal properties meet to a working temperature of composites below 300 °C. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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6. Characterization of potential cellulose fiber from cattail fiber: A study on micro/nano structure and other properties.
- Author
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Wu, Shanshan, Zhang, Jinlong, Li, Chuangye, Wang, Fuli, Shi, Lanlan, Tao, Mengxue, Weng, Beibei, Yan, Bin, Guo, Yong, and Chen, Yuxia
- Subjects
- *
CELLULOSE fibers , *TYPHA , *FOURIER transform infrared spectroscopy , *LIGNIN structure , *LIGNANS , *PROSPECTING , *FIBERS , *TRANSMISSION electron microscopy - Abstract
Exploration of the application prospects of cattail fibers (CFs) in natural composites, and other fields is important for the sustainable development of new, green, light-weight, functional biomass materials. In this study, the physical and chemical properties, micro/nano structure, and mechanical characteristics of CFs were investigated. The CFs have a low density (618.0 kg m−3). The results of transmission electron microscopy and tensile testing data indicated that the cattail trunk fiber (CTF) bundle is composed of parenchyma cells and solid stone cells, demonstrating high specific modulus (10.1 MPa∙m3·kg−1) and high elongation at break (3.9%). In turn, the cattail branch fiber (CBF) bundle is composed of parenchyma cells with specific "half-honeycomb" shape. The inner diaphragms divide these cells into the open cavities. This structural feature endows the CTF bundles with stable structure, good oil absorption and storage capacities. The chemical component and the Fourier transform infrared spectroscopy analyses show that the CFs have higher lignin content (20.6%) and wax content (11.5%), which are conducive to the improvement of corrosion resistance, thermal stability and lipophilic–hydrophobic property of CF. Finally, the thermogravimetric analysis indicates that its final degradation temperature is 404.5 °C, which is beneficial to the increase in processability of CFs-reinforced composites. • The cattail fiber (CF) has lower density and multi-cavity structure. • Higher wax content endows CF with lipophilic-hydrophobic potential. • The cattail branch fiber (CBF) has "half-honeycomb" shape and inner diaphragms. • The CBF structural feature gives CF stable structure and good oil storage capacities. • The cattail trunk fiber bundles exhibit excellent mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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