128 / 2021-11-15 19:16:00

AGRICULTURE-RESIDUAL PARENCHYMA CELLS FOR NANOCELLULOSE: AN ALTERNATIVE TO CONVENTIONAL FIBROUS RESOURCES

Corn stalk pith,Bagasse pith,Parenchyma cellulose,Cationic-cellulose nanoparticles,Cellulose nanofibrils

Parenchyma cellulose, which was extracted from an abundantly agricultural residues such as corn stalk pith (CSP) and bagasse pith (BP), was demonstrated to be the sustainable source for fabricating different types of nanocellulose materials. The first study was designed to obtain cellulose nanoparticles (CNPs) from waste CSP via a sono-assisted glycidyltrimethylammonium chloride (GTMAC) etherification followed by an ultrasonication treatment. This modification could improve the ultrasound disintegration of cellulose from sheet-like parenchyma cells into nanoparticles. The formation of CNPs by ultrasonication was largely dependent on the cellulose consistency in the cationic modified system. Under the condition of 25% cellulose consistency, the longer ultrasonic-treated duration yielded a more stable and dispersible suspension of CNP due to its higher zeta potential. Degree of substitution and FT-IR analyses indicated that quaternary ammonium salts were grafted onto hydroxyl groups of cellulose chain. SEM and TEM images exhibited the CNP to have spherical morphology with an average dimeter from 15 to 55 nm. XRD investigation revealed that CNPs consisted mainly of a crystalline cellulose Ι structure, and they had a lower crystallinity than the starting cellulose. The optimal CNPs with highly cationic charges and good stability might be considered as one of the alternatively renewable reinforcement additives or antibacterial supports for nanocomposite production. In the second work, parenchyma cellulose from BP was applied as an alternative raw material to produce cellulose nanofibrils (CNFs) through one-step mechano-partial dissolution by ball milling with N, N’-dimethylacetamide (DMAC)/LiCl₂ binary system. The outcome revealed that BP parenchyma cellulose was easily dissociated, and as-obtained CNFs had the diameters of 30-200 nm and lengths of several micrometers. Subsequently, BP nanofibrils and dissolved cellulose was formed to the wet-stable nanopaper during the regeneration process in water bath with addition of sorbitol as a plasticizer, showing high transparency up to 95.8% at 800 nm. This nanopaper with water content of 50% had the favorable break elongation of 101%, toughness of 0.712 MJ/m³ and low Young’s modulus of 4.3 MPa, which were closed to the mechanical properties of human skins. Such remarkable features can bring about potential applications in stretchable electronics as a substrate and visible wound-dressing materials.