Biocomposite Films of Polylactic Acid Reinforced with Microcrystalline Cellulose from Pineapple Leaf Fibers

Poly(lactic acid) (PLA) composite films reinforced with microcrystalline cellulose (MCC) extracted from pineapple leaf fibers (PALF) were prepared by a solution casting procedure. In an attempt to improve the interaction between PLA and cellulose, two approaches were adopted; first, poly(ethylene glycol) (PEG) was used as a surfactant, and second, the cellulosic fibers were pre-treated using tert-butanol (TBA). Lignocellulosic and cellulosic substrates were characterized using Fourier transform infrared (FTIR), wide-angle X-ray scattering (WAXS), and thermogravimetrical analysis (TGA). MCC from PALF showed good thermal stability, left few residues after decomposing, and exhibited high crystallinity index. Mechanical, thermal and thermomechanical properties of the PLA composites were also evaluated. Multiple PLA endotherms were observed in composites with TBA-treated MCC due to crystal nucleation effects. The ultimate tensile strain values for all composites were lower than that of the pristine PLA. However, 4 wt. % MCC content provided balanced engineering properties in terms of static and dynamic tensile properties.