Properties of nanoclay-PVA composite materials

Abstract

Background: Polymer-clay nanocomposite (PCN) materials have become a focus of research due to their unique characteristics and potential commercial applications. Clay addition in polymers improves their properties and may result in better features. PCN materials are reported to have enhanced thermal, mechanical, flame retardation, corrosion protection characteristics. Objectives: This study investigates the effect of different loading concentrations of Na-rich montmorillonite (MMT) clay when they are effectively dispersed in a organic polyvinyl alcohol (PVA) matrix. Methods: PCN materials were prepared using the solution method. The structure morphology of the PCN was studied using x-ray diffraction (XRD) and NSEM. FTIR was applied to study the molecular structure of the PCN. The mechanical properties of the pure PVA and PCN were studied. The thermal stability of the PCN was studied using TGA and differential scanning calorimetry (DSC). Results: The morphological images and crystalline morphology indicated that PVA and MMT clay has intercalated by the uniform and homogenous dispersion and confinement of the PVA polymer chains within silicate layers of the clay. PCN XRD pattern has a high d-spacing compared to the pure MMT clay XRD pattern, which has a low d-spacing (Fig. 1). FTIR showed that as the loading of MMT clay increases, the intensities of the MMT clay bands become stronger in the FTIR spectra of PCN (Fig. 2). NSEM results showed that intercalation that took place between the PVA and MMT. It was found that the small amount of MMT clay made the tensile modulus and elongation percentage the PCN significantly higher than the pure PVA, due to polymer-clay intercalation. Thermal stability results showed that the PCN is more thermally stable than pure PVA. Conclusions: The excellent MMT nanoclay dispersion in PVA matrix leads to significantly enhanced mechanical properties, notably an increase in tensile moduli with significant increase in tensile strength, maximum load and percentage elongation of the PVA due to adding the small amount of MMT clay. The uniform and homogenous dispersion of MMT in PVA matrix results in an increase in thermal decomposition temperature and glass transition temperature of the promoted PVA polymer based on TGA (Fig. 3) and DSC (Fig. 4) results.