共查询到10条相似文献,搜索用时 0 毫秒
1.
Zirconia-toughened mullite (SiC/ZTM) nanocomposites were prepared by a chemical precipitation method. The samples showed good sinterability and could be densified to >98.7% of the theoretical density at 1350°–1550°C. Because of the addition of mullite seeds in the starting powder and the pinning effects of ZrO2 and SiC particles on mullite grain growth, a fine-grained microstructure formed. Mullite grains were generally equiaxed for the sample sintered at 1400°C; whereas, for the sample sintered at 1550°C, most mullite grains took a needlelike morphology, and SiC particles were primarily located within mullite grains. The strength and toughness increased with the increasing sintering temperature, and reached their respective maximum of 780 MPa and 3.7 MPa·m1/2 for the sample sintered at 1550°C. 相似文献
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Panagiotis Dallas Radek Zboril Athanasios B. Bourlinos Dalibor Jancik Dimitrios Niarchos Ales Panacek Dimitrios Petridis 《大分子材料与工程》2010,295(2):108-114
The synthesis of silver nanoparticles attached on the surface of a hollow cornet‐like polymer matrix which served as a reductant and host matrix is described. This hybrid organic/inorganic macromolecular matrix is exhibiting anion‐exchange properties, porous structure and hollow morphologies, and absorptions in the visible light region. Due to the anion‐exchange property and the 3D orientation of the macromolecular chains the material is defining a new functional organic/inorganic hybrid. For the synthesis of nanoparticles, no other reducing agents were used and silver nanoparticles with a mean diameter of less than 20 nm were attached on the surface of the polymer, thus inheriting the composite with high antibacterial activity tested in bacterial strains and yeasts.
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Zahra Abdollahi Ehsan Nazarzadeh Zare Fatemeh Salimi Iran Goudarzi Franklin R. Tay Pooyan Makvandi 《International journal of molecular sciences》2021,22(5)
In this study, nanocomposite hydrogels composed of sodium carboxymethylated starch (CMS)-containing CuO nanoparticles (CMS@CuO) were synthesized and used as experimental wound healing materials. The hydrogels were fabricated by a solution-casting technique using citric acid as a crosslinking agent. They were characterized by Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) to evaluate their physicochemical properties. In addition, swelling, antibacterial activities, antioxidant activities, cytotoxicity, and in vivo wound healing were investigated to evaluate the wound healing potential of the CMS@CuO nanocomposite hydrogels. Growth inhibition of the Gram-positive and Gram-negative pathogens, antioxidant activity, and swelling were observed in the CMS@CuO nanocomposite hydrogels containing 2 wt.% and 4 wt.% CuO nanoparticles. The hydrogel containing 2 wt.% CuO nanoparticles displayed low toxicity to human fibroblasts and exhibited good biocompatibility. Wounds created in rats and treated with the CMS@2%CuO nanocomposite hydrogel healed within 13 days, whereas wounds were still present when treated for the same time-period with CMS only. The impact of antibacterial and antioxidant activities on accelerating wound healing could be ascribed to the antibacterial and antioxidant activities of the nanocomposite hydrogel. Incorporation of CuO nanoparticles in the hydrogel improved its antibacterial properties, antioxidant activity, and degree of swelling. The present nanocomposite hydrogel has the potential to be used clinically as a novel wound healing material. 相似文献
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以聚氨酯弹性体(Polyurethane Elastomers,PUE)为基体,以具有高介电常数的铜酞菁齐聚物(Copper phthalocyanine oligomer,CuPc)为填料,并且为改善两者的相容性,通过化学方法将部分CuPc接枝到聚合物链上,制备了具有高介电常数的聚合物基纳米复合材料。在100Hz时,CuPc含量为15wt%的纳米复合材料的介电常数高达440左右,是PUE与CuPc简单共混物的8倍多。介电常数的迅速提高归功于CuPc粒子在纳米复合材料中分散性的改善与粒径的大大减小导致的复合体系中界面交换耦合效应的显著增加。 相似文献
5.
Yin Liu Wei Lian Wanfu Su Juhua Luo Luming Wang 《International Journal of Applied Ceramic Technology》2020,17(1):205-210
With coal gangue and high alumina refractory solid wastes as raw materials, needle-like mullite powder, with an average diameter of about 1 μm, was synthesized at 1300°C by using the conventional solid-state reaction method. Mullite ceramics were derived from the inexpensive needle-like powder. Phase composition was examined by using X-ray diffraction (XRD), while morphologies of the ceramics were observed by using scanning electron microscopy. The content and distribution of elements in the sintered samples were characterized with energy dispersive spectrometer and X-ray fluorescence spectroscopy. Mechanical properties of the mullite ceramics were studied by using the three-point bending method. The aspect ratio of the needle-like mullite particles was up to 6. The mullite sample sintered at 1500°C for 3 hours had a density of 2.515 g·cm−3, which was slightly lower than the theoretical density. Maximum fracture toughness and bending strength of the mullite ceramics were 1.82 MPa·m1/2 and 71.76 MPa, respectively. This study realizes the resource utilization of gangue and high alumina refractory solid wastes, and the prepared mullite ceramics have good application prospect. 相似文献
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《分离科学与技术》2012,47(16):2518-2524
Synthesis of porous high oil-absorbing resins by high internal phase emulsions (HIPEs) as template was described. Lauryl methacrylate (LMA), hexadecyl methacrylate (HMA), and steary methacrylate (SMA) with long-chain alkyl groups were chosen as monomers to prepare high oil-absorbing resins. Effects of different factors including initiator, crosslinker, emulsifying agent, porogen, reaction temperature, reaction time, and volume ratio of water/oil on oil-absorbing capacity were discussed. The maximum capacities of the high oil-absorbing resins prepared by LMA, HMA, and SMA were 24 g.g?1, 32 g.g?1, and 34 g.g?1 in trichloromethane, respectively. The oil-absorbing capacities of these resins remain constant after three times desorption and absorption processes. 相似文献
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Agnieszka Jaboska-Wawrzycka Patrycja Rogala Grzegorz Czerwonka Katarzyna Gaczyska Marcin Drabik Magdalena Daczuk 《International journal of molecular sciences》2021,22(18)
Antimicrobial resistance is a growing public health concern that requires urgent action. Biofilm-associated resistance to antimicrobials begins at the attachment phase and increases as the biofilms maturate. Hence, interrupting the initial binding process of bacteria to surfaces is essential to effectively prevent biofilm-associated problems. Herein, we have evaluated the antibacterial and anti-biofilm activities of three ruthenium complexes in different oxidation states with 2-pyridin-2-yl-1H-benzimidazole (L1 = 2,2′-PyBIm): [(η6-p-cymene)RuIIClL1]PF6 (Ru(II) complex), mer-[RuIIICl3(CH3CN)L1]·L1·3H2O (Ru(III) complex), (H2L1)2[RuIIICl4(CH3CN)2]2[RuIVCl4(CH3CN)2]·2Cl·6H2O (Ru(III/IV) complex). The biological activity of the compounds was screened against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. The results indicated that the anti-biofilm activity of the Ru complexes at concentration of 1 mM was better than that of the ligand alone against the P. aeruginosa PAO1. It means that ligand, in combination with ruthenium ion, shows a synergistic effect. The effect of the Ru complexes on cell surface properties was determined by the contact angle and zeta potential values. The electric and physical properties of the microbial surface are useful tools for the examined aggregation phenomenon and disruption of the adhesion. Considering that intermolecular interactions are important and largely define the functions of compounds, we examined interactions in the crystals of the Ru complexes using the Hirshfeld surface analysis. 相似文献
9.
Zhongxiang Bai Tianyou Wang Xin Zheng Yanping Huang Yining Chen Weihua Dan 《Polymer Engineering and Science》2021,61(1):278-287
Hydrogels have great potential applications in biomedical materials, but their applications in complex physiological environments are severely limited by their weak strength and biotoxicity. Generally, synthetic polymer hydrogels and natural polymer hydrogels have complementary advantages in terms of mechanical strength and biological activity. Herein, tannic acid (TA), a natural material, was introduced into the polyvinyl alcohol/collagen (PVA-COL) double network to prepare a hydrogel (PVA-COL-TA) with good bioactivity and mechanical properties. The tensile strength of the composite hydrogel can reach up to 20 times that of the pure PVA hydrogel. And the hydrogel after swelling under physiological conditions also exhibits stable mechanical properties. The introduction of TA can reduce the degradation rate of COL, enabling it to continue to exert biological activity. in vitro cytocompatibility experiments showed that PVA-COL-TA hydrogel has good sustained biological activity and the potential for biomedical materials. 相似文献
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Electrospun composite mats of poly[(D,L ‐lactide)‐co‐glycolide] and collagen with high porosities of 85–90% and extended pore sizes of 90–130 µm were prepared to mimic the ECM morphologically and chemically. The existence of collagen molecules on the fiber surface was confirmed, enabling the cells to find enhanced binding sites for their integrin receptors. The mechanical data for the blended fibrous mats indicated that they were sufficiently durable for dermal tissue engineering. Fibroblasts derived from GFP transgenic C57BL/6 mice were used to directly observe cell proliferation, and the inoculation of collagen enhanced cell attachment, proliferation and extracellular matrix secretion, which were found to be dependent on the amount of collagen in the composite scaffold.