Influence of green extraction process of nano fibrillated cellulose using subcritical water/CO2 on its properties and development of its bio composite

Abstract

AbstractThe study proposes a new green extraction method of producing nano fibrillated cellulose (NFC) from softwood pulp (SWP) by using subcritical water/CO2. Subcritical water/CO2 led to a controlled hydrolysis of SWP and the treated SWP was fibrillated by sonication to produce NFC. Effect of process parameters (time, temperature, and pressure) on the crystallinity and thermal properties of NFC was studied to optimize the process conditions for controlled hydrolysis. The influence of the extraction process on the properties of prepared NFC was studied. Nanocellulosic materials were characterized by using field emission scanning electron microscopy, transmission electron microscopy, Fourier‐transform infrared spectroscopy, wide‐angle X‐ray diffraction, and thermo gravimetric analysis. The NFC obtained at optimum process conditions (100 bar, 145°C, and 30 min) showed significantly high crystallinity (66%) and high yield (75–80%) compared to the NFC prepared by conventional mechanical grinding method. The present method of producing NFC uses water and pressurized CO2, and therefore, eliminate use of acids and chemicals. Plasticized poly vinyl alcohol (p‐PVA) based nano composite with NFC shows significant improvement in thermal stability (36%), tensile strength (77%) with reduced water vapor transmission rate as compared to virgin p‐PVA indicating their potential as nanofiller for making bio composites.