Investigation of the large plastic deformation of iPP induced by plane strain compression: Stress–strain behavior and thermo-mechanical properties

A description of a specific device and a method to measure accurately large plastic deformation parameters in semicrystalline polymers induced by Plane Strain compression is presented. A force magnification of 22:1 was obtained which permitted the performance of Plane Strain Compression deformation experiments until 22 ton load. Stress values up to 300 MPa as well as strains (compression ratios) until 70% were accurately measured. Five commercial polypropylene grades with different molar mass (Mw) namely, 161,800, 228,600, 419,800, 448,400 and 708,900 g/mol were studied. The behavior of the stress–strain curves in relation to the deformation temperature, the Mw and the main features and properties obtained by Densimetry, DMA and DSC analyses of the plastically deformed polypropylene samples are presented and discussed.