Rapid densification mechanism and properties of h-BN/ZrO2 composites with oxide additives by spark plasma sintering

Large size high density h-BN/ZrO₂ composites (ø = 110 mm, h = 15 mm) were rapidly prepared by spark plasma sintering (SPS) with sintering cycle 20 min. The effects of additives on the mechanical properties, microstructure evolution, and corrosion resistance of the h-BN/ZrO₂ composites were studied. The Al₂O₃, MgO, SiO₂, La₂O₃ and ZrO₂ rapidly formed heterogeneous eutectic crystals under the action of SPS. The low eutectic compounds significantly promoted the diffusion of h-BN or ZrO₂, also increased the density. The flexural strength of h-BN/ZrO₂ composites could reach 196.31 MPa, and the apparent porosity was only 0.42 %. The additives are combined with zirconia to form a high viscosity eutectic, whose corrosion resistance to molten steel is obviously better than that of single ZrO₂. The corrosion depth of h-BN/ZrO₂ composites was only 114 µm after corroded in molten steel at 1550 °C for 80 min. The comprehensive properties of h-BN/ZrO₂ composites were obviously improved by appropriate additives.     

Study of elementary reactions of free radicals formed on oxide and platinum containing catalysts

The formation of alkylperoxy radicals on catalysts CuCr₂O₄/ -Al₂O₃, Pt /--Al₂O₃ and on alumina upon the interaction of amines and alcohols with oxygen has been observed applying the matrix isolation ESR technique. Surface-generated gas phase radicals are shown to initiate a radical chain reaction. The efficiency of the yield of radicals depends on the catalyst mass and its arrangement in a reactor: the desorption of radicals into the gas phase occurs primarily from the outer geometrical surface of catalyst granules.     

有机玻璃的增韧研究

研究了不同聚合方法制备的聚丙烯酸丁酯（PBA）对浇铸型有机玻璃（PMMA）的增韧改性，研究结果表明，当PBA以纳米粒子簇分散在PMMA基体中时，对PMMA有较好的增韧改性效果。当PMMA中无皂乳液聚合PBA（e-PBA)的质量分数为0.5%时。改性PMMA的冲击强度比基体提高38%。SEM观察表明，本体聚合PBA（b-PBA)橡胶粒子以独特的纳米簇状结构均匀分布在PMMA基体中，大量的微裂纹以b-PBA粒子为中心呈放射状向外辐射，这些微裂纹在试样破坏的过程中吸收了大量的冲击能，使改性PMMA韧性得以提高。     

PPO/PA合金的研制

比较了三条技术路线、PPO／PA质量比、各种抗冲击剂对PPO／PA合金性能的影响。应用FTIR．Molau实验、DSC曲线证实了改性反应原理及增容作用。结果表明：在双螺杆挤出机中，聚苯醚(PPO)与马来酸酐(MAH)接枝反应，然后与聚酰胺(PA66)、SEBS挤出共混，制成的PPO／PA合金，抗冲击性能高。     

氧化钐填充PP加工流变行为的研究

用转矩流变仪和毛细管流变仪研究了稀土氧化钐(Sm2O3)对聚丙烯(PP)塑化性能和流变行为的影响。结果表明，Sm2O3能够促进PP的塑化；PP／Sm2O3和纯PP一样，同属于非牛顿假塑性流体行为，PP／Sm2O3的非牛顿指数普遍大于纯PP而更趋于牛顿性流体；在相同温度和剪切速率下，PP／Sm2O3和纯PP的粘流活化能比较接近；Sm2O3加入PP后，体系的流动性和加工稳定性得到了明显改善。     

卤代双磷酸酯阻燃剂的合成研究

以PCl3、季戊四醇、溴水及环氧乙烷为原料，四氯化钛为催化剂，合成了一种新型卤代双磷酸酯阻燃剂——2，2-二溴甲基-1，3-亚丙基双(2-氯乙基2-溴乙基磷酸酯)；用IR、元素分析对其进行了表征。结果表明：在各步反应过程中分别按照各步反应的量的比、温度、时间等最佳反应条件进行反应，产物的收率可达92％。     

纳米CeO2的制备方法研究进展

介绍了近年来纳米CeO2的制备方法的研究进展情况，重点分析对比了沉淀法、溶胶—凝胶法、水热法、微乳液法、喷雾热分解法、喷雾反应法等制备纳米CeO2的优缺点，指出了在今后应重点研究和解决的主要问题。     

纳米碳酸钙在涂料中的应用研究

探究纳米碳酸钙先在溶剂中分散再与树脂进行调配的方法。利用正交设计法对其中高速搅拌法进行优惠条件实验，发现搅拌时间并非越长越好，优惠条件下涂料中纳米碳酸钙分散到原始粒径，涂料质量有较大提高。     

Propylene epoxidation over Ti/MCM-41 catalysts prepared by chemical vapor deposition

Ti-containing mesoporous catalysts were prepared by chemical vapor deposition (CVD) of TiCl₄ on silica MCM-41 in the 700–900 °C temperature range. These samples were characterized (with XRD, ICP, nitrogen adsorption, FT-IR, ESCA, and TEM) and evaluated for the epoxidation of propylene with two alkyl hydroperoxides. The increase of CVD temperature resulted in the decrease of titanium content, catalyst hydroxyl population, crystallinity, and surface area. Catalyst selectivity to the desired product – propylene oxide – was highly sensitive to the deposition temperature. The best Ti/MCM-41 catalyst was prepared at the temperature of 800 °C, which had the maximum propylene oxide yield of 94.3%.     

聚酰胺6纳米复合材料的新进展

介绍了聚酰胺 6纳米复合材料的研究进展 ,并给出了其 5种制备方法。对纳米粒子增强增韧机理与PA6单体插入聚合制纳米复合材料的反应模式作了简介。