Preparation and Reinforcement of Polylactic Acid/ Nanofibrillated Cellulose/ Glycidyl Methacrylate Composites

Abstract

Using polylactic acid (PLA) and nanocellulose (NFC) as raw materials, and glycidyl methacrylate (GMA) as the modifier, the PLA/NFC-GMA composite was prepared by solution blending. The addition of GMA effectively improved the dispersion of NFC in PLA, with NFC being grafted onto the PLA molecular chain through a reaction with GMA. The tensile strength of PLA/NFC-GMA composites increased with NFC loading, while GMA improved interfacial compatibility and dispersion, leading to a non-monotonic strength trend and reduced elongation at break. The PLA/NFC-GMA composite with 0.7 wt.% NFC and 6.0 wt.% GMA had the best mechanical properties, with the tensile strength of 27.7 MPa and the elongation at break of 78.4%. The PLA/NFC-GMA composite exhibited excellent UV shielding. Its transmittance was nearly zero below 280 nm and it maintained high transparency within the wavelength range of 400 to 800 nm, with a transmittance exceeding 85%. The transparency of the composite reached its maximum when the NFC and GMA loadings were 0.7 and 1.5 wt.% relative to PLA, respectively. GMA significantly enhanced the thermal stability of PLA/NFC-GMA composites. The thermal stabilization effect of GMA became saturated at ~3.0 wt.%, beyond which additional GMA primarily promoted more complete volatilization without further improving thermal resistance.