322 resultados para 841-6
Resumo:
The morphology and mechanical behaviour of phenolphthalein poly(ether ether ketone) (PEK-C)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) blends has been investigated. A poly(ethylene oxide)-b-polystyrene-b-poly(ethylene oxide) (PEO-PS-PEO) triblock copolymer was used as compatibilizer. It was found that PEO-PS-PEO has a compatibilizing effect on the PEK-C/PPO blends. The addition of PEO-PS-PEO to the blends greatly improves phase dispersion and interfacial interfacial adhesion and also enhances the ultimate tensile strength and Young's modulus at compositions ranging from 30 to 70% PEK-C. However, all the values of the ultimate tensile strength within the whole composition range are lower than those expected by simple additivity, probably owing to the poor mechanical properties of PEO-PS-PEO copolymer.
Resumo:
经过铝粉加热活化的AlCl_3与SmCl_3在苯中反应,得到了Sm(η~6—C_6H_6)(AlCl_4)_3·C_6H_6单晶.其晶体属于三斜晶系,P1空间群,晶胞参数a=9.456(2)(?),b=9.765(3)(?),c=16.776(4)(?),α=96.00(2)°,β=93.76(2)°,γ=111.66(2)°,V=1422.55(?)~3,Z=2.晶体结构是采用Patterson和Fourier合成法解出的,所有非氢原子的坐标及各向异性热振动参数经块矩阵最小二乘法修正,最后偏离因子R=0.031,R_ω=0.035.分子结构中,中心离子Sm(Ⅲ)与六个Cl原子及一个苯环上的六个C原子成键.Sm-C键平均距离2.92(?),Sm-Cl平均距离2.83(?).与希土相连的六个Cl原子,其中之五构成平面五边形,整个分子呈大致的五角双锥形.
Resumo:
中性Π配体过渡金属,特别是钛的有机配合物的合成和结构已有较深入的研究。但是含中性Π配体的稀土有机配合物的合成研究刚刚开始。1986年,Cotton等人报道了第一个这种类型的配合物Sm(η~6C_6Me_6)(η~2AlCl_4)_3。研究中性π配体稀土有机配合物的合成、结构及性能,对于揭示f元素的成