The effects of nanoclay on thermal, mechanical and rheological properties of LLDPE/chitosan blend

Abstract The objective of this study was to prepare linear low density polyethylene (LLDPE)/chitosan/closite nanocomposites by using various concentrations of LLDPE, chitosan, and closite clay mineral. The nanocomposites were then characterized for their thermal, mechanical, and rheological properties by using different analytical techniques including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), rheological characterization, tensile strength study, and scanning electron microscopy. The TGA demonstrated that crosslinked composites are thermally more stable than non-crosslinked composites. The DSC stated that the percentage crystallinity of crosslinked composites is lower than the non-crosslinked composites. It is also observed that the increasing quantity of chitosan and closite also reduces the percentage crystallinity of the prepared nanocomposites. Rheological characterization revealed that, crosslinked composites are viscoelastic in nature and have high complex viscosities (η*) and high dynamic shear storage modulus (G′), while non-crosslinked composites showed high dynamic shear loss modulus (G″). Tensile strength of crosslinked composites was much higher than non-crosslinked composites, however elongation at break (Eb) values of non-crosslinked composites are higher than crosslinked composites. The scanning electron microscopy displayed strong adhesion between matrix-filler-interphase in crosslinked composites, while some gaps were also observed in non-crosslinked composites. As a conclusion, chitosan, closite clay, and the LLDPE based nanocomposites with improved thermal, mechanical, and rheological properties can be successfully prepared by employing a peroxide-initiated melt compounding technique.