The effect of nanoclay on the creation of clusters of polyamide 6 microfibrils

Abstract

The PA6/clay nanocomposites were prepared during in-situ anionic ring-opening polymerization (AROP) via reactive melt blending in a Hakke internal mixer. Then, the samples were characterized using FT-IR, DSC, DMTA, rheometer, XRD, SEM/EDX/elemental mapping, TEM, and HT-GPC to study the effects of Cloisite 15A on PA6 properties. The results showed that nanoclay caused a decrease in the ultimate tensile strength (UTS), crystallinity, Tm, Tg, and tan δ of the samples. However, it increased the Young′s modulus and stress rupture of the samples. Furthermore, the nanocomposites showed a pseudo-solid behavior because of the reinforcing effect of the nanoparticles. Additionally, α crystals were not seen in the samples with 1 and 3 % nanoclay; however, γ crystals were observable in those samples. Also, nanoclay decreased PA6 viscosity and increased dispersity and residual monomers in the nanocomposite samples. The nanoclays exfoliated in the sample have 0.5 % nanoparticles, but they were intercalated by more loading in the PA6 matrix. Moreover, the PA6 microfibrils were observed as sporadic and clay-centered clusters in the SEM micrographs of the pure and nanocomposite samples, respectively. Therefore, the clustering of PA6 microfibrils in the matrix during in-situ AROP is considered a novelty in current research.

Keywords

• polyamide 6
• nanoclay
• nanocomposites
• clusters
• in-situ polymerization