Physical, thermal, chemical and rheological characterization of cellulosic microfibrils and microparticles produced from soybean hulls
Abstract Soybean hulls were used to isolate cellulosic microfibrils (SMF) and brick like microparticles (SMP) by combining chemical and mechanical pretreatments. The key physical and chemical features of SMF and SMP were compared with those of micro and nanofibrillated cellulose (MNFC) obtained from fully bleached wood fibers. SMF and SMP chemical composition includes residual polysaccharides and lignin that endow such biologically derived materials with properties typical of nanocellulosics. Compared to MNFC, SMF and SMP exhibit enhanced crystallinity 10% higher) and thermal stability (onset degradation temperature >295 degC and maximum degradation at 361 and 355 degC) Such observations make SMF and SMP suitable for reinforcement in thermoplastic composites. A strong shear thinning behavior was observed for aqueous dispersions of SMF and SMP, revealing that these cellulose microstructures are of interest for rheology modification, coatings and films. Overall, the availability and low cost of biomass from residual soybean hulls constitutes a viable option for their use as a feedstock for the production and development of novel materials from SMF and SMP.