Thermal and dynamic mechanical properties of PP/EVA nanocomposites containing organo-modified layered double hydroxides

Abstract

Abstract In this study, organo-modified layered double hydroxides (LDH) as nanoparticleswere used to prepare hybrid nanocomposites based on polypropylene (PP), ethylene vinyl acetate copolymer (EVA) blend in presence of a maleated polypropylene (PP-g-MA) as compatibilizer via a one-step melt mixing process. Transmission electron microscope (TEM) was employed to determine localization of LDH nanoparticles in the blend nanocomposites. Microstructures of the nanocomposites were studied by means of scanning electron microscopy (SEM). Thermo-mechanical properties of nanocomposites were investigated by dynamic mechanical thermal analysis (DMTA). Differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) were also used to investigate crystallization behavior and degradation process of the nanocomposites, respectively. The results showed that, LDH nanoparticles in the exfoliated and/or intercalated states were mainly localized in the EVA phase. The average particles size of EVA domains was reduced in presence of LDH and PP-g-MA. The storage modulus of nanocomposites was controlled by combination of LDH and PP-g-MA. The crystallization studies revealed that 5wt%LDH and PP-g-MA increased crystallization temperature to 133.4 °C while addition ofLDH in absence of the compatibilizer decreased the crystallization temperature to 122.7 °C.Investigation of thermal degradation behavior of samples indicated that presence of LDH and PP-g-MA in PP/EVA blendsimprovedinitial degradation temperature of nanocomposites by about 43% compared to the neat PP.