Surface texture and percolation effects in microporous oriented films of polyolefins
Ivan Kuryndin2012, Physics of the Solid State
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Abstract
The surface structure of polypropylene and polyethylene microporous films prepared by the extrusion of the polymer melt with the subsequent stages of annealing, uniaxial extension, and thermal fixa tion of the samples has been analyzed using scanning electron microscopy. It has been shown that percolation through pores corresponds to the axial texture of the surface with the channel structure described by the frac tal cluster model. The transition from open pores (through flow channels) to closed pores leads to the forma tion of surface regions with a biaxial texture. An increase in the density of the solid phase cluster is accompa nied by the formation of a homogeneous biaxial texture with a period of alternation of the density in two mutually perpendicular directions, one of which coincides with the direction of orientation of the films.
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