Physical and mechanical properties of polyvinyl alcohol and polypropylene composite materials reinforced with fibril aggregates isolated from regenerated cellulose fibers

Natural fibers in micro and nano scales may be a potential alternative for man-made fibers because of the comparable mechanical properties to those of glass, carbon, and aramid fibers. Cellulose fibril and fibril aggregate are generally prepared by physical treatments, e.g., high-pressure homogenizer, or chemical treatments, e.g., acid hydrolysis. In this study, fibril aggregates were generated from a regenerated cellulose fiber by a novel mechanical treatment. The geometrical characteristics of the fibers and the fibril aggregates were investigated using scanning electron microscopy (SEM) and polarized light microscopy (PLM), and its crystallinity was investigated by wide angle X-ray diffraction (WAXD). The degree of fibrillation of the fibers was indirectly evaluated by water retention value (WRV). Nano-biocomposites reinforced with fibril aggregates were prepared by film casting and compression molding and evaluated by tensile test. The morphological characteristics of the nanocomposites were investigated with SEM and PLM. As reference, commercial microfibrillated cellulose was also used to reinforce biodegradable polymer.