Effect of nanoclay on the properties of low density polyethylene/linear low density polyethylene/thermoplastic starch blend films

• Higher nanoclay content improves platelet delamination in LDPE/LLDPE/TPS blends.
• Both nanoclay and PE-g-MA reduce TPS domain size and deform their particles.
• LDPE/LLDPE/TPS nanocomposites show higher performance than the pure blends.
• LDPE/LLDPE/TPS blends with 5phr nanoclay satisfy required packaging properties.
• LDPE/LLDPE/TPS nanocomposite films are environmentally friendly materials.

The aim of this work is to study effect of nanoclay (Cloisite®15A) on morphology and properties of low-density polyethylene/linear low-density polyethylene/thermoplastic starch (LDPE/LLDPE/TPS) blend films. LDPE/LLDPE blend (70/30 wt/wt) containing 15 wt.% TPS in the presence of PE-grafted maleic anhydride (PE-g-MA, 3 wt.%) with 1, 3 and 5 phr of nanoclay are compounded in a twin-screw extruder and then film blown using a blowing machine. Nanocomposites with intercalated structures are obtained, based on the X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. However, some exfoliated single platelets in the samples are also observable. Scanning electron microscopic (SEM) images confirm the ability of both exfoliated nanoclay and PE-g-MA to reduce the size of TPS domains and deform their particles within the PE matrices. As the nanoclay content increases from 1 to 5 phr, the tensile strength, tear resistance and impact strength of the films increase, whereas a slight decrease in the elongation at break is observed. The film samples with 5 phr nanoclay possess the required packaging properties, as specified by ASTM D4635. These films provide desired optical transparency and surface roughness which are more attractive for packaging applications.