Isolation of high crystalline nanocellulose from Mimosa pudica plant fibres with potential in packaging applications

Abstract

Mimosa pudica Linn (sensitive plant) is a medicinal plant of family Fabaceae. Its stem is a good source of cellulose. This research work reports isolation of cellulose nanocrystals (CNCs) from M. pudica stem fibres by combined chemical and mechanical treatments. Polyvinyl alcohol (PVA)/starch composites were prepared with incorporation of isolated CNC (1, 3 and 5 wt.%) by solution casting method. Addition of CNC in polymer composites improved its mechanical strength and barrier properties. Isolation process of CNC includes alkali treatment, bleaching and acid hydrolysis followed by homogenization. Chemical composition, thermal stability, structure, surface morphology, crystallinity and size of the freeze‐dried nanocellulose were studied carefully. Fourier transform infrared analysis of raw fibre and CNC showed elimination of non‐cellulosic fragments from untreated M. pudica stem fibre. Electron microscopy analysis and dynamic light scattering (DLS) confirmed the isolation of nanocellulose. X‐ray diffraction showed improvement in the crystallinity of obtained nanocellulose. Increase in crystallinity indicates high Young's modulus of isolated nanocellulose which makes them proper reinforcement material in composites. Polymer composites with the addition of 3 wt.% of CNC showed the highest tensile strength and lowest water vapour transmission rate (WVTR), moisture absorption and oxygen transmission rate (OTR). As M. pudica is an abundant natural resource, it can be utilized as an efficient source of nanocellulose for different applications especially as fillers in sustainable polymer composites for packaging.

Recent advances in cellulose nanocrystals-based sensors: a review

“…A polymer matrix reinforced with CNCs shows high mechanical strength and is thus used in aerospace and automotive industries. 137 CNCs are optically active and transparent and so they can be used as optical films for touchscreen displays, eyewear, window coatings, and wearable electronics. CNCs possess a high aspect ratio (i.e., a high length : breadth ratio) and are hence used for reinforcement and incorporated with paper and cardboard, polymers, plastics, rubber, etc.…”

Current and Potential Applications of Green Membranes with Nanocellulose

“…Since nanocellulose is harvested from plant fibers, it can naturally decompose over time, eliminating the issue of waste generation. Representative research works conducted in this area include the isolation of high crystalline nanocellulose from Mimosa pudica plant fibers for packaging applications [ 1 ], as well as applying nanocellulose as a starch-based packaging material for food [ 13 ]. While at its current stage of development, nanocellulose may not replace plastics entirely as the primary packaging option due to the profit-prioritizing business model of industries; however, it does help promote improvements to address modern issues in our society, such as improved gas barrier properties of the packaging materials.…”

“…In recent years, one such material has been nanocellulose. Nanocellulose is a naturally occurring nanomaterial extracted from the cell walls of plant fibers, plant biomass, and algae [ 1 , 2 ]. This green nanomaterial can be obtained either as nanocrystalline/nanofiber cellulose via top-down biosynthesis by disintegration of plant materials or as bacterial nanocellulose through bottom-up biosynthesis [ 3 , 4 , 5 ].…”

“…Nanocellulose is characterized by chemical inertness, high tensile strength, and biocompatibility; in addition, it exhibits dimensional stability, a low coefficient of thermal expansion, and the ability to modify its surface chemistry [ 6 , 7 , 8 , 9 , 10 ]. In recent studies, these unique properties of nanocellulose have been enhanced and applied to processes in the areas of water purification [ 11 ], automotive [ 12 ], food [ 1 , 13 ], and membrane separations [ 14 ]. The industry prioritizes the low cost and efficient production involved in utilizing nanocellulose as an alternative to conventional cellulose.…”