Abstract
Nanocomposites of poly(vinylidene fluoride) (PVDF) filled with Lucentite STNTM organically modified silicate (OMS) were investigated upon melt-crystallization at temperatures near its melting point (i.e., at low supercooling temperatures). Previously, we showed that the addition of extremely small amounts of OMS into PVDF causes the polar beta phase formation in cold-crystallized samples, and causes polar gamma phase formation in melt-crystallized samples under high supercooling. The current study focused on the impact of OMS on polymorphic behavior of PVDF crystallized from the molten state, or annealed, at low supercooling temperatures. Nanocomposites with 0–4.0 wt% concentration were prepared from solutions. The existence of α or γ phase was verified by using Fourier transform infrared spectroscopy, wide-angle X-Ray scattering or Differential Scanning Calorimetry (DSC). Morphology of α- and γ-spherulites was observed by polarizing optical microscopy (POM). In annealed PVDF/OMS nanocomposites, gamma crystals were observed to dominate at all clay compositions except 0.01 wt%. DSC and POM data show that two types of gamma crystals, γ and γ’, exist when PVDF/OMS nanocomposites were annealed.