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Youxian Hu Zhenlin Jiang Min Zhu Shiqiang Song Liang Jin Hong Ji Chaosheng Wang Jianhua Wang 《乙烯基与添加剂工艺杂志》2021,27(2):432-444
Polyester is widely used in household products because of its good mechanical properties and wears resistance, but polyester is easy to ignite and inclined to produce droplet, so its application range is limited. The cross-linkable magnesium hydroxide nanoparticles were incorporated into flame-retardant polyester, which enables the phosphorus-containing copolyester with thermal cross-linking and anti-meltdrop properties. The nanoparticles were achieved by in situ polymerization and acted as a nucleating agent for improving the crystalline properties of the copolyester. Furthermore, the nanoparticles also enhanced anti-meltdrop properties and reduced the heat and gas release during the combustion process of the copolyester. The maximum heat release rate and total smoke release reduced by 39.8% and 74.4% compared with pure polyester. Specifically, the combustion products of the nanoparticles and phosphorus flame retardant could act a barrier role by covering the carbon layer to isolate air and heat, thereby resulting in excellent anti-meltdrop properties. The simple modification method reported here realizes the collaborative modification of flame retardant and anti-meltdrop properties of phosphorous flame-retardant copolyesters by thermal cross-linking. 相似文献
44.
Mg-Al-Zn(RE)镁合金轧制变形行为及强化机制 总被引:1,自引:0,他引:1
针对典型的Mg-Al-Zn系AZ31变形镁合金以及添加了0.8%Ce和0.8%Nd的AZ31镁合金,研究了合金在轧制加工过程中组织与性能的变化以及稀土元素对合金的影响,并探讨了合金的主要强化机制。结果表明:Mg-Al-Zn系合金轧制加工过程中加丁硬化严重,容易发生脆性断裂。添加稀土元素后的合金强度和塑性都有明显提高,稀土元素可形成Al4ce等含稀土化合物,起到细晶强化和第二相强化作用。 相似文献
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THE APPARENT VISCOSITY OF SEMI-SOLID AZ91D ALLOY AT STEADY STATE 总被引:2,自引:0,他引:2
Z.S. Zhen W.M. Mao S.J. Van A.M. Zhao C.L. Cui X.Y. ZhongSchool of Materials Science Engineering University of Science Technology Beijing Beijing China 《金属学报(英文版)》2002,15(6):505-510
The rheological behavior of semi-solid AZ91D at steady state is studied using a Couette type viscometer in the present paper. The results show that the apparent viscosity of semi-solid AZ91D at the steady state increases with the solid fraction increasing, and goes up sharply when the solid fraction reaches a certain value, which is called critical fraction. In addition, the apparent viscosity of semi-solid AZ91D at the steady state takes on a distinct downtrend with the shearing rate increasing, which indicates a strong shear thinning property. In addition, the critical solid fraction becomes higher under larger shearing rate, owing to the more globular shape of the solid particles. Based on the present experiment results, an empirical equation is built as that, relating the steady state apparent viscosity of semi-solid AZ91D with the solid fraction fs andshearing rate (?) at the same time: ηapp=10.74exp(6.95fs)(?)-0.86. 相似文献
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Mg-xwt.%CuY (x=15, 20, 25) composites were successfully prepared by reactive mechanical alloying (RMA).X-ray diffraction (XRD) measurement shows that main phases of the as milled composites are MgH2 and Mg2Cu, and they converted into Mg and MgCu2 after dehydrogenation, respectively.Pressure-Composition-Isotherm (PCI) test shows that the composites exhibit double pressure plateau at each isothermal desorption process.The hydrogen absorption and desorption kinetics of the composites become worse with increasing x content, indicating that Mg-Cu phase has a negative effect on the hydrogen sorption properties of the composites.It is supposed that the good hydrogen sorption properties of the composites attribute to the catalyst effect of yttrium hydride distributed in Mg substrate and the particles size reduction and crystal defects formed by RMA. 相似文献
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通过对两种不同加工工艺(金属型铸造、触变成形)AZ91D镁合金在完全相同电解液中进行的两组相同的微弧氧化实验,研究基材对微弧氧化过程的影响,探索电流-处理时间的变化规律。实验证明,基体对微弧氧化过程的起弧电压及电流-时间变化曲线有明显影响,但对膜层厚度、孔隙率及电流-时间变化曲线的影响不大。电流在整个实验过程中呈波浪形减小,并最终伴随二次起弧的发生。短时间、大电流的方法可以生成一定厚度的致密陶瓷层(20~30μm),表面光洁度较高,而且有利于节能。两组实验的实验现象无明显差异。 相似文献
49.
Kristf Kdr Viktria Juhsz Anna Fldes Rbert Rcz Yan Zhang Heike Lchli Erzsbet Kat Lszl Kles Martin C. Steward Pamela DenBesten Gbor Varga kos Zsembery 《International journal of molecular sciences》2021,22(8)
TRPM7 plays an important role in cellular Ca2+, Zn2+ and Mg2+ homeostasis. TRPM7 channels are abundantly expressed in ameloblasts and, in the absence of TRPM7, dental enamel is hypomineralized. The potential role of TRPM7 channels in Ca2+ transport during amelogenesis was investigated in the HAT-7 rat ameloblast cell line. The cells showed strong TRPM7 mRNA and protein expression. Characteristic TRPM7 transmembrane currents were observed, which increased in the absence of intracellular Mg2+ ([Mg2+]i), were reduced by elevated [Mg2+]i, and were inhibited by the TRPM7 inhibitors NS8593 and FTY720. Mibefradil evoked similar currents, which were suppressed by elevated [Mg2+]i, reducing extracellular pH stimulated transmembrane currents, which were inhibited by FTY720. Naltriben and mibefradil both evoked Ca2+ influx, which was further enhanced by the acidic intracellular conditions. The SOCE inhibitor BTP2 blocked Ca2+ entry induced by naltriben but not by mibefradil. Thus, in HAT-7 cells, TRPM7 may serves both as a potential modulator of Orai-dependent Ca2+ uptake and as an independent Ca2+ entry pathway sensitive to pH. Therefore, TRPM7 may contribute directly to transepithelial Ca2+ transport in amelogenesis. 相似文献