Cavitation in strained polyvinylidene fluoride: mechanical and X-ray experimental studies

PolyVinylidene Fluoride (PVDF) is a polar crystalline polymer commonly foun d in the apolar alpha crystalline form studied here. The complementarity of a macroscopic (tensile tests at constant crosshead speed) and a microscopi c approach (Small-Angle X-ray Scattering and Wide-Angle X-ray Scattering) s pecifies the cavitation phenomenon occurring in this material when strained . Ar room temperature, microvoids nucleate predominantly in equatorial intr aspherulitic amorphous layers, just before the yield. For further strains, these defects grow in the tensile direction and damage affects a larger are a of spherulites. This process, combined with classical amorphous shear mec hanisms, prevails in PVDF deformation as crystallite fragmentation remains of minor importance, for axial strains of up to 30%. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.