Cryogenic Mechanical Properties of PP/MMT Polymer Nanocomposites

Abstract

This article addresses the effect of Na+-Montmorillonite (MMT) on cryogenic mechanical properties of polypropylene (PP). Polypropylene/Montmorillonite (PP/MMT) nanocomposites were prepared by using twin-screw extruder incorporating the polypropylene grafted maleic anhydride (PP-g-mA) as compatibilizer is used for better dispersion of nanoclay in the polymer matrix. The dispersion and exfoliation of MMT in the nanocomposites were observed using transmission electron microscopy (TEM) and X-ray diffraction(X-RD). Mechanical behaviors of PP/MMT nanocomposites at both room temperature (RT) and liquid nitrogen temperature (77 K) were investigated in terms of tensile, flexural and impact properties. The mechanical results showed that the tensile strength of PP/MMT nanocomposites at both RT and 77 K reached the maximum at the 5wt. % MMT content, increased by 3.1% and 13.2%, respectively, as compared with those of pure PP sample. The notched impact strength at RT increased from 22.33 J/m for the pure PP matrix to 36.53 J/m for the nanocomposite with the 5wt% MMT content. The fracture surfaces of neat PP and PP/MMT nanocomposites were examined using Scanning Electron Microscopy (SEM). Finally, the dependence of the storage modulus and loss modulus of the MMT content was examined by Dynamic Mechanical Analyzer (DMA) at cryogenic temperature.