POLY (L-LACTIC ACID)/LAYERED SILICATE NANOCOMPOSITE BLOWN FILM FOR PACKAGING APPLICATION: THERMAL, MECHANICAL AND BARRIER PROPERTIES

In an attempt to alleviate the global solid waste disposal problem and to reduce the dependence on petroleum-based plastics for packaging materials, biodegradable and compostable thermoplastic polymers are required. Polylactic acid (PLLA) is a highly versatile biodegradable polymer derived from 100% renewable resources. Three types of PLA nanocomposites containing 1, 3 and 5 phr of nanoclay were compounded in a co-rotating twin screw extruder, to study the effect of nanoclay content on film processibility of composites as well as properties of blown films. Differential scanning calorimetry (DSC) showed that the cold crystallization and melting temperatures were influenced by the presence of nanoclay. The thermogravimetric analysis (TGA) showed increase in the decomposition temperature for all of the nanocomposites. Mechanical properties of the nanocomposite film showed that the elongation (%) increased up to 3 phr of clay whereas tensile strength and modulus increased only up to 1 phr of the nanoclay. Nanocomposite films showed an improvement in oxygen barrier and water vapor barrier in comparison to the neat PLA up to 3 phr of nanoclay.