Phase characterization and mechanical and flame‐retarding properties of nano‐CaSO4/polypropylene and nano‐Ca3(PO4)2/polypropylene composites

An in situ deposition approach was used for the synthesis of nano‐CaSO₄ and nano‐Ca₃(PO₄)₂. The nanosize particles were confirmed with an X‐ray diffraction technique. Composites of polypropylene (PP) with 0.1–0.5 wt % nano‐ or commercial CaSO₄ or nano‐Ca₃(PO₄)₂ were prepared. The transition from the α phase to the β phase was observed for 0.1–0.3 wt % nano‐CaSO₄/PP and nano‐Ca₃(PO₄)₂/PP composites. This was confirmed by Fourier transform infrared. A differential scanning calorimetry analysis was carried out to determine the thermal behavior of the nanocomposites with increasing amounts of the nano‐CaSO₄ and nano‐Ca₃(PO₄)₂ fillers. Increases in the tensile strength and Young's modulus were observed up to certain loading and were followed by a decrease in the tensile strength. A continuous decrease in the elongation at break (%) was also observed for commercial CaSO₄ and larger nano‐Ca₃(PO₄)₂. A decrease in the mechanical properties after a certain loading might have been due to the agglomeration and phase transition of PP in the composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 670–680, 2007     

氧化焰烧成铜红釉

本研究以SiC作还原剂，采用氧化焰烧成，试制成功了在1250～1260℃下烧成的铜红釉，克服了传统的还原焙烧成方法的不足，简化了生产工艺，提高了铜红釉的成品率。     

火焰发射光谱法联合测定磷矿石和磷精矿中氧化钾及氧化钠

采用双通道的FP-640火焰光度计对磷矿中钾、钠元素进行联合测定试验。试验结果表明：在0．1％～1.0％区间内，K2O的相对标准偏差(RSD)为1．88％～2．93％，回收率为96．6％～102．7％；Na2O的相对标准偏差(RSD)为1．05％～2．10％，回收率为97．3％～101．2％。     

我国阻燃剂行业状况

介绍了我国阻燃剂的生产现状、开发前景及相关法律保障。涉及的阻燃剂有十溴二苯醚、十溴二苯乙烷、溴化环氧树脂、四溴双酚A、六溴环十二烷、硅系阻燃剂、磷系阻燃剂、三嗪系阻燃剂和无机阻燃剂等。     

Discrete-continual model of flame propagation in a gas suspension of metal particles. I. One-dimensional approximation

Experimental data on combustion of magnesium particles in oxygen-containing gas mixtures are analyzed and generalized, which allowed us to develop a semi-empirical mathematical model that takes into account the integral effect of the initial particle size, pressure, and velocity of the oxidizing flow on combustion. Flame propagation in an air suspension of fine magnesium particles is considered in a one-dimensional approximation. For this purpose, a discrete-continual model of flame propagation in a gas suspension of metal particles is developed. The flammability limits in a vessel, caused by heat losses into the ambient medium and by spatial nonuniformity of the distribution of disperse-phase particles, are numerically determined, and the influence of nonuniformity and bidispersion of a one-dimensional ensemble of particles on flame characteristics is studied.__________Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 2, pp. 81–93, March–April, 2005.     

微波消解-火焰原子吸收法测定污泥中的铜、锌

建立了一种微波消解样品、火焰原子吸收法测定污水厂污泥中铜、锌含量的方法。在实验条件下,测定污泥中铜、锌的回收率分别为95%～104%,96%～105%,RSD﹤5%。方法操作简便、快速、准确、灵敏、重复性好,可用于污泥中铜、锌的测定。     

新型有机磷系阻燃剂的热稳定性

利用STA490C热分析仪对8种新型有机磷系阻燃剂的热失重过程进行测定和对比,结果表明磷杂螺环阻燃剂3,9-二羟基-2,4,8,10-四氧杂-3,9-二磷杂螺环[5,5]十一烷-3,9-二氧化物和苯基次膦酸类阻燃剂4-甲氧基羟甲基苯基次膦酸热稳定性较好。     

Photocatalytic mineralisation of organic compounds: a comparison of flame-made TiO2 catalysts

A comparative photocatalytic analysis was carried out on TiO₂ made in a Flame Spray Pyrolysis (FSP) process and flame-made Degussa P25. Both have similar crystallinity, phase composition, phase segregation and a non-porous surface. Hence comparison was made based on their difference in specific surface area, organic adsorption and the amount of OH• generated upon illumination. The photocatalytic activity tests were carried out using the following series of organic compounds: sucrose, glucose, fructose, maleic acid, glyoxylic acid, oxalic acid, isobutyric acid, phenol and methanol. FSP-made TiO₂ outperformed P25 for saccharides mineralisation, while for phenol and methanol mineralisation P25 was better than FSP-made TiO₂. Similar mineralisation rates were observed for both FSP-made and P25 TiO₂ for the mineralisation of carboxylic acids. This shows that the relative performance of the photocatalysts depends on the type of organic compounds to be degraded. The high surface area and possibly a more efficient interfacial charge transfer of FSP-made TiO₂ provided an efficient pathway for saccharides mineralisation. As for phenol and methanol, the mineralisation rates were higher when using P25 due to the greater amount of OH• radicals generated by this photocatalyst. The fast mineralisation rates of carboxylic acids made degradation of these organic compounds to be less affected by the TiO₂ photocatalyst properties and conditions tested in this work.