利用小角X射线散射技术研究组分对聚酰亚胺/Al2O3杂化薄膜界面特性与分形特征的影响

采用溶胶-凝胶方法制备无机纳米杂化聚酰亚胺(PI),应用同步辐射小角X射线散射(SAXS)方法研究不同组分杂化PI薄膜的界面特性与分形特征.研究结果表明:散射曲线不遵守Porod定理,形成负偏离,说明薄膜中有机相与Al₂O₃纳米颗粒间存在界面层,界面层厚度在0.54 nm到1.48 nm范围内;随无机纳米组分增加,界面层厚度增加,有机相与无机相作用变强;无机纳米颗粒同时具有质量分形和表面分形特征,其分布、集结是一种非线性动力学过程;随组分增加,其质量分形维数降低 关键词： 小角X射线散射 纳米杂化 聚酰亚胺 界面     

Small-Angle X-Ray Scattering Study on Nanostructures of Polyimide Films

Inorganic nanohybrid polyimide （PI） is widely applied in electrical and electronic devices for its outstanding insulating properties. Samples IOOCR and IOONH are made in Dupont. Among them, IOONH is a kind of pure PI films; however, IOOCR is a kind of inorganic nanohybrid PI films with excellent corona-resistance. The nanostructure of PI films is investigated with small-angle x-ray scattering technique and transmission electron microscopy （TEM）. The normalized volume fractions of the scatterers in the specimens are obtained with a tangent-by-tangent data analysis for the small-angle x-ray scattering data. The multi-hierarchical scatterers of IOONH can be divided into two dominant components, i.e., the sharp component and the wide component. The sharp component is corresponding to the contribution of PI molecular chains, and the wide component includes the aggregates formed by PI molecular chains and the film has nested dual-fractal characteristics, nevertheless the IOOCR film possesses three types of scale scattering made up of inorganic nanoparticles, molecular chains and aggregates. The present films have multi-fractal structures. The distribution and structure of scattering body of two kinds of PI films are analyzed. The results of SAXS agree well with those of TEM methods.     

Increasing Superplasticity and Strong Dynamic Behaviour of Zr--Cu--Ni--Al Bulk Metallic Glass

The plasticity and the dynamic fragility of bulk metallic glass of a Zr62 CuxsNiloAllo alloy are studied by three- point beam bending methods. We find that the alloy behaves super plastic not only at room temperature, but also at high temperatures. More importantly, it is found that the superplasticity increases with increasing temperature. In addition, the dynamic fragility parameter m for the supercooled liquid of this alloy is measured to be 34.87 and the supercooled liquid of Zr62 CuxsNixoAlxo alloy behaves as a strong liquid.