Thermal Properties, Water Vapor Permeability and Morphology of Polylactic Acid Bionanocomposites

The present study developed an improved nanocomposite based on polylactic acid (PLA) biopolymer. The structural properties of PLA nanocomposites of clay and cellulose nanoparticles were evaluated for level and water vapor permeability (WVP) using thermal and casting methods. Thermal tests (DSC) showed that pure PLA had a glass transition point (Tg) of 53.83, a melting point (Tm) of 153.95°C and crystallization (x%) of 41.36%. With the incorporation of clay nanoparticles, Tg and x% increased, while Tm showed no significant change. The micro-crystal cellulose (MCC) nanoparticles were not compatible with the polymer matrix, so there was no effect on the thermal properties. WVP results showed that pure PLA had high permeability; the addition of clay nanoparticles strongly decreased WVP. The sample with 7% clay had a permeability of 0.92×10-11 g/m.S.Pa. WVP of the film increased significantly as a result of the hydrophilic nature of the MCC. The SEM images of the samples confirmed the results.