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 ( M w) 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 M w and the main features and properties obtained by Densimetry, DMA and DSC analyses of the plastically deformed polypropylene samples are presented and discussed.