Structural evolution of PVDF during storage or annealing

Michael Neidhöfer (1) , Francois Beaume (1) , Laurent Ibos (2) , Alain Bernes (3) , Colette Lacabanne (3)

1 CERDATO - Centre de recherche, développement, applications et technique de l'ouest
2 CERTES EA 3481 - Centre d'Etudes et Recherches en Thermique, Environnement et Systèmes [Créteil]
3 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

The effect of annealing PVDF at temperatures above Tg and below Tm was investigated by differential scanning calorimetry (DSC), thermostimulated current spectroscopy (TSC) and solid-state NMR. This study evidences a progressive structural evolution, taking place during such annealing. Its characteristics (kinetics and its temperature dependence, lack of reversibility at lower temperature over extended periods of time, double organization corresponding to double annealing with unmodified kinetics) point to a mechanism of secondary crystallization as described by Marand et al. In addition to the formation of extra crystalline (hence rigid) material, this phenomenon is believed to generate increasing conformational constraints in the residual amorphous material. Accordingly, a progressive reduction of the molecular mobility was demonstrated by NMR during annealing.

Mots clés: Secondary crystallization; Aging; Annealing

Domaines: Polymères

Michael Neidhöfer, Francois Beaume, Laurent Ibos, Alain Bernes, Colette Lacabanne. Structural evolution of PVDF during storage or annealing. Polymer, 2004, 4 (5), pp.1679-1688. ⟨10.1016/j.polymer.2003.12.066⟩. ⟨hal-03602717⟩