Physico-mechanical properties of polylactic acid bio-nanocomposites filled by hybrid nanoparticles

This study is aimed to investigate the effect of the simultaneous incorporation of cellulose nanocrystals (CNC) and silver nanoparticles (SN) on the mechanical, biodegradability, and water vapor permeability of polylactic acid (PLA)-based films. PLA films and their nanocomposites containing different levels of CNC (0.333, 1 and 1.667 phr) and SN (0.333 phr) were prepared by solution casting method. CNC was reacted with acetic anhydride to improve its compatibility and miscibility with PLA. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), tensile test, and water vapor permeability and antibacterial tests were employed to characterize the samples. The biodegradability was assessed by measuring the weight loss upon burial in the soil. FTIR spectroscopy confirmed the modification of cellulose nanocrystals. TGA test showed that partial acetylation slightly improved the thermal stability of CNC. The presence of cellulose nanocrystals increased the tensile strength and modulus of elasticity of the nanocomposite relative to pure polylactic acid. The biodegradability and water vapor permeability of the samples decreased upon CNC incorporation. The antibacterial properties of the films showed the higher resistance of the gram-positive bacteria as their cell walls include a peptidoglycan layer.