Study on morphology evolution and fractal character of the miscible blend between isotactic polypropylene and copolymer of ethylene and propylene

The compatibility of isotactic polypropylene (iPP) with a block copolymer of ethylene and propylene (mEP) was evaluated by glass transition temperature measurements and Han curves. The morphology of the dispersed phase in alloys of iPP with mEP was observed by scanning electron microscopy (SEM). The average diameters, dp, of the dispersed phase in iPP/mEP alloys were calculated from SEM images. The results indicated that dp depends on the composition and mixing condition of the alloys. The distribution of dp was studied using graph-estimation methods and found to be log-normal in character. The calculated standard deviation, sigma, characterizes the dispersed phase particle distribution width, and depends on the composition and mixing conditions of the blends. The fractal behavior of the phase morphology shown by SEM images of the alloys was studied, and the fractal dimensions were calculated by the changing coarse-graining level and measure relations methods. The self-similarity of the systems is discussed. The fractal dimensions depend on the composition and mixing conditions of the alloys. (C) 2009 Elsevier Ltd. All rights reserved.