Nanocomposites based on polyethylene and Mg–Al layered double hydroxide: characterisation of modified clay,morphological and rheological analysis of nanocomposites

Abstract

Magnesium and aluminium based layered double hydroxide (Mg–Al LDH) after modification with anionic surfactant has been used as nanoclay to prepare polyethylene based nanocomposites using the melt mixing technique. The modified Mg–Al LDH has interlayer separation about four times higher than the unmodified clay and also low surface tension. The modified clay also possesses similar platelet type particle morphology like pristine clay. X-ray diffraction and electron microscopic analyses reveal that the nanocomposites are mainly exfoliated/intercalated type characterised by the presence of hierarchy of clay particle morphology in the matrix. The dispersed particle forms aggregates or localised domains of network structure. As a result, response to steady shear is characterised by the presence of stress overshoot at the start-up flows, especially at higher LDH concentrations. The rheological analysis shows that the dispersed LDH particles caused deviation of linear viscoelastic response of the melt from that of the unfilled polyethylene.