The effect of polyethylene graft maleic anhydride compatibilizer on the physical, mechanical, and thermal properties of extruded noncross-linked low-density polyethylene nanocomposite foams

Abstract

An investigation was carried out on the noncross-linked low-density polyethylene (LDPE) nanocomposite foams with polyethylene graft maleic anhydride (PE-g-MA) compatibilizer. Nanocomposite foams with similar densities were produced by extrusion method, and the effect of organophilic montmorillonite (OMMT) nanoclay (closite20A) content on cell microstructure, mechanical properties, thermal conductivity, and flame retardancy of samples were studied. X-ray diffraction (XRD) was used to investigate the nanoclay dispersion in LDPE matrix. In XRD patterns of LDPE nanocomposite foams, closite20A characteristic peak was not observed as an evidence of nanoclay intercalation–exfoliation in the polymer matrix. For increasing the compatibility of PE and nanoclay, PE-g-MA compatibilizer was used. Due to the presence of compatibilizer in the nanocomposite foams and decreasing the cell nucleation energy around the nanoclay, the average cell size was reduced, but the cell density and microstructure uniformity increased. Furthermore, the compatibilized nanocomposites showed lower thermal conductivity and burning rate than that of the nanocomposites without PE-g-MA compatibilizer and neat LDPE foams, which can be attributed to the cell size reduction as well as distribution of cells of narrow size in nanocomposite foams.