Enhanced thermal stability and mechanical property of EVA nanocomposites upon addition of organo-intercalated LDH nanoparticles

Abstract

Organo-intercalated layered double hydroxides (LDHs)/ethylene vinyl acetate (EVA) nanocomposites were synthesized using the solution blending method. Pristine layered double hydroxides are not compatible with hydrophobic polymer matrix due to their hydrophilic property. As an attempt to improve the compatibility of LDHs with hydrophobic EVA, positively charged LDH surface was modified by incorporating various anionic surfactants. Surfactants were selected by considering the length of aliphatic chains conjugated with and without an aromatic ring such as sodium dodecyl sulfate (DS), sodium dodecylbenzene sulfonate (DBS), and stearate (SA). The organo-intercalated LDHs into EVA resulted in enhanced thermal stability (Delta T-0.5 = 7-19 degrees C, T-0.5: temperature at 50 wt% weight loss) and mechanical strength of the EVA nanocomposites depending on the type and the loading concentration of organo-intercalated LDHs compared to these of intact EVA. Especially, SA-LDH had higher enhancement efficiency in elongation at break than DS-LDH and DBS-LDH. It is, therefore, concluded that organo-intercalated LDHs using suitable anionic surfactants are potential inorganic materials that can be considered as a nanofiller with high thermal stability and mechanical property.