聚乙烯催化剂表面分形和多重分形特征

应用分形和多重分形理论研究了负载型聚乙烯催化剂(简称催化剂)表面形态。提出一种图片处理和计算过程更加完备的基于扫描电子显微镜照片的分形维数和多重分形谱计算程序,对4种催化剂进行分析计算。探讨了分形维数、多重分形谱相关参数与催化剂表面形态及与聚合活性的对应关系。实验结果表明,催化剂表面形态的复杂程度可以用表面分形维数来表征,聚合活性高的催化剂表面形态更加复杂,有更大的比表面积,对应的分形维数值也越大。催化剂表面分形维数的变化程度可以用多重分形谱来表征,聚合活性高的催化剂表面分形维数的跨度和分散程度更高。提出的分形维数和多重分形谱计算程序为催化剂的评定与设计提供了一种实用的手段。

Fractal and Multi-Fractal Analysis of Surface Morphology of Polyethylene Catalyst

The surface morphology of supported polyethylene catalyst was investigated guided by fractal and multi-fractal theory.Based on scanning electron microscope(SEM)images of polyethylene(PE)catalyst,the fractal and multi-fractal computer program was developed.For four supported PE catalysts,the relationship between activity of the catalysts and their surface morphologies,and parameters of fractal dimension and multi-fractal curves were studied.Complexity of catalyst surface could be characterized by surface fractal dimension and catalyst activity rose with heightening of complexity and its specific surface area.Variety of fractal dimensions could be characterized by multi-fractal curves.Catalyst activity increased with broadening of span and rising of fractal dimension distribution.The fractal and multi-fractal computer program was a reliable approach for evaluation and design of PE catalyst.