Efeito do envelhecimento e da geração de “whitening” no comportamento mecânico do PVDF

Abstract

The polyvinylidene (PVDF) is a polymer with high chemical and mechanical resistence, for this reason is being largely used in the composition of flexible pipes used in petroleum production offshore, acting as sealing layer. One effect named whitening can appear in the material, being characterized by the formation of whitened regions and is associated with cavitation process (growth of microvoids). This work has the objective of studying the effect of PVDF aging in petroleum during 30, 90 and 180 days at 80 ° C and the generation of whitening that was generated by traction tests by cyclic loading. Test specimens were aged in petroleum before and after the generation of the whitening effect and for comparative purposes a group of specimens did not undergo generation of whitening, just been aged. To evaluate the mechanical behavior, tensile tests were carried out and X-ray diffraction, differential scanning calorimetry and infrared spectroscopy were used for crystallinity analysis.