Surface Morphology and Deformation Behavior of Polypropylene Single Crystals

Abstract

As part of an investigation into the nature and properties of crystalline polymers, the morphology and deformation behavior of polypropylene (PP) single crystals have been examined. The study includes single crystals of the whole polymer as well as single crystals grown from each of three PP fractions (Mn = 740, 1260 and 1880). The structure of the crystal surfaces and the mechanical response of each of the single crystals to a tensile strain have been examined. Results have been obtained which indicate how the morphology of the crystal surface may be altered through the use of specific thermal and/or chemical treatments. A correlation has been found to exist between the surface morphology and deformation behavior of the PP single crystals. Two possible mechanisms are proposed to explain this relation between these single crystal properties. It is shown that the combined use of metal decoration procedures and a quantitative analysis of the deformation behavior of PP single crystals provides a powerful technique for studying the properties of polymer crystal surfaces.