Structure of the Grafted Polyethylene-Based Palladium Catalysts: WAXS and ASAXS Study
Structure of the Grafted Polyethylene-Based Palladium Catalysts: WAXS and ASAXS Study
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接枝聚乙烯基钯催化剂的结构：WAXS 和 ASAXS 研究
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
K. Ekman
中科院分区：
文献类型：
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作者：
K. Jokela;R. Serimaa;M. Torkkeli;V. Eteläniemi;K. Ekman
用广角和反常小角X射线散射（WAXS，ASAXS）方法研究了接枝聚乙烯基钯催化剂的结构，并探讨了接枝材料聚苯乙烯、聚丙烯酸和聚4-乙烯基吡啶对催化剂结构的影响。样品的Pd含量为约5%，并且使用相同的还原剂HCHO将Pd（II）还原为Pd（0）。起始聚乙烯纤维是半结晶的，并且这种结构在不同的制备过程中没有被破坏。Pd盐在样品中没有结晶，并且在聚（4-乙烯基吡啶）接枝的样品中形成最小的Pd（II）颗粒。在将Pd（II）还原为Pd（0）之后，分别在聚（丙烯酸）和聚苯乙烯接枝的样品中形成平均尺寸为35和60 A的Pd（0）微晶。聚（4-乙烯基吡啶）接枝的还原样品不含Pd（0）微晶。Pd（0）颗粒显示出比Pd（II）颗粒小的趋势。音量
Wide and anomalous small-angle X-ray scattering (WAXS, ASAXS) methods were used to study the structure of the grafted polyethylene-based palladium catalysts and to find out how the grafting material, polystyrene, poly(acrylic acid), or poly(4-vinylpyridine), affects the structure of the catalyst. The Pd content of the samples was about 5% and Pd(II) was reduced to Pd(0) using the same reducing agent, HCHO. The starting polyethylene fiber was semicrystalline and this structure was not destroyed in the different preparation processes. Pd salts did not crystallize in the samples and the smallest Pd(II) particles were formed in the poly(4-vinylpyridine) grafted sample. Pd(0) crystallites with the average sizes of 35 and 60 A were formed in the poly(acrylic acid)- and polystyrene-grafted samples, respectively, after reduction of Pd(II) to Pd(0). The poly(4-vinylpyridine)-grafted reduced sample did not contain Pd(0) crystallites. Pd(0) particles showed a tendency to be smaller than Pd(II) particles. The volume ...