Polyamide-caly nanocomposites and their non-linear viscoelastic characterization

Synthesis and rheology of polyamide-clay nanocomposites was carried out to address the molecular chain ordering and relaxation behavior observed when the melt responds non-linearly to deformations. The hybrid was prepared by anionic polymerization at 165°C from e-caprolactam, a catalyst and a co-catalyst and the monomer intercalated montmorillonite. Step strain and steady shear viscoelastic experiments were performed and the influence of increasing clay content was observed. The relaxation moduli showed time-strain separable behavior and the steady shear response exhibited rapid shear thinning with increasing clay content. The non-linear behavior was modeled with a conventional constitutive equation of time-strain separable type and the difficulties of this approach were identified.