Cellulose is the most abundant biopolymer on Earth, found in trees, waste from agricultural crops and other biomass The fibres that comprise cellulose can be broken down into building blocks, known as fibrillated cellulose, of varying, controllable dimensions that extend to the nanoscale Fibrillated cellulose is harvested from renewable resources, so its sustainability potential combined with its other functional properties (mechanical, optical, thermal and fluidic, for example) gives this nanomaterial unique technological appeal Here we explore the use of fibrillated cellulose in the fabrication of materials ranging from composites and macrofibres, to thin films, porous membranes and gels We discuss research directions for the practical exploitation of these structures and the remaining challenges to overcome before fibrillated cellulose materials can reach their full potential Finally, we highlight some key issues towards successful manufacturing scale-up of this family of materials

Developing fibrillated cellulose as a sustainable technological material.

Highly open porous biodegradable poly(L-lactic acid) ¿PLLA scaffolds for tissue regeneration were fabricated by using ammonium bicarbonate as an efficient gas foaming agent as well as a particulate porogen salt. A binary mixture of PLLA-solvent gel containing dispersed ammonium bicarbonate salt particles, which became a paste state, was cast in a mold and subsequently immersed in a hot water solution to permit the evolution of ammonia and carbon dioxide within the solidifying polymer matrix. This resulted in the expansion of pores within the polymer matrix to a great extent, leading to well interconnected macroporous scaffolds having mean pore diameters of around 300-400 microm, ideal for high-density cell seeding. Rat hepatocytes seeded into the scaffolds exhibited about 95% seeding efficiency and up to 40% viability at 1 day after the seeding. The novelty of this new method is that the PLLA paste containing ammonium bicarbonate salt particles can be easily handled and molded into any shape, allowing for fabricating a wide range of temporal tissue scaffolds requiring a specific shape and geometry.

A Novel Fabrication Method of Macroporous Biodegradable Polymer Scaffolds Using Gas Foaming Salt as Porogen Additive

Over the past few years, nanocellulose (NC), cellulose in the form of nanostructures, has been proved to be one of the most prominent green materials of modern times. NC materials have gained growing interests owing to their attractive and excellent characteristics such as abundance, high aspect ratio, better mechanical properties, renewability, and biocompatibility. The abundant hydroxyl functional groups allow a wide range of functionalizations via chemical reactions, leading to developing various materials with tunable features. In this review, recent advances in the preparation, modification, and emerging application of nanocellulose, especially cellulose nanocrystals (CNCs), are described and discussed based on the analysis of the latest investigations (particularly for the reports of the past 3 years). We start with a concise background of cellulose, its structural organization as well as the nomenclature of cellulose nanomaterials for beginners in this field. Then, different experimental procedures for the production of nanocelluloses, their properties, and functionalization approaches were elaborated. Furthermore, a number of recent and emerging uses of nanocellulose in nanocomposites, Pickering emulsifiers, wood adhesives, wastewater treatment, as well as in new evolving biomedical applications are presented. Finally, the challenges and opportunities of NC-based emerging materials are discussed.

/pdf/nanocellulose-from-fundamentals-to-advanced-applications-ecdehj4ngu.pdf

Nanocellulose: From Fundamentals to Advanced Applications

Renewable and sustainable biobased materials: An assessment on biofibers, biofilms, biopolymers and biocomposites

How do trees support their upright massive bodies? The support comes from the incredibly strong and stiff, and highly crystalline nanoscale fibrils of extended cellulose chains, called cellulose nanofibers. Cellulose nanofibers and their crystalline parts-cellulose nanocrystals, collectively nanocelluloses, are therefore the recent hot materials to incorporate in man-made sustainable, environmentally sound, and mechanically strong materials. Nanocelluloses are generally obtained through a top-down process, during or after which the original surface chemistry and interface interactions can be dramatically changed. Therefore, surface and interface engineering are extremely important when nanocellulosic materials with a bottom-up process are fabricated. Herein, the main focus is on promising chemical modification and nonmodification approaches, aiming to prospect this hot topic from novel aspects, including nanocellulose-, chemistry-, and process-oriented surface and interface engineering for advanced nanocellulosic materials. The reinforcement of nanocelluloses in some functional materials, such as structural materials, films, filaments, aerogels, and foams, is discussed, relating to tailored surface and/or interface engineering. Although some of the nanocellulosic products have already reached the industrial arena, it is hoped that more and more nanocellulose-based products will become available in everyday life in the next few years.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adma.202002264

Surface and Interface Engineering for Nanocellulosic Advanced Materials.

Commercial application of cellulose nano-composites - A review.

Process optimization for the production of cellulose nanocrystals from rice straw derived α-cellulose

Superior effect on thermal, mechanical and optical properties of cellulose acetate nanocomposite (CA) films has been established by its fabrication with rice straw derived cellulose nanofibers (RS CNFs) as nano filler. The ratio of CA/RS CNF were optimized (2, 5, 7.5 and 10 wt % of CNF) through solvent casting method, their effect on the thermal, mechanical and optical properties of the nanocomposite films were observed. Better crystallinity index (92%) and lower lignin content of RS CNF (up to 5 wt % loading) enhanced tensile strength to 65 MPa and Young’s modulus up to 2.5 GPa of CA film. The improvement of thermal and optical properties were understood by the enhancement in thermal stability and transparency through TGA and UV–Vis spectrophotometer respectively in higher loading of CNFs. The improvised CA nanocomposite film with RS CNFs keeps better future and promise in packaging and logistic industries as superior to commercial CA films.

Fabrication of cellulose acetate nanocomposite films with lignocelluosic nanofiber filler for superior effect on thermal, mechanical and optical properties

The present review describes the application of lignocellulosic biomass-derived nanocellulose for wastewater remediation with a focus on the removal of heavy metals. Nanocellulose and its nanocomposite are among the emerging materials of this century, with an abundance of application in the versatile field of composites, medicines, functional additives, and water treatment. Water treatment has received attention from the commercial and academic sector, with a large emphasis on one of the biggest problems faced by humans in the 21st century i.e., clean potable water. There are various sources of water pollution including heavy metal toxifications. The applications of cellulose and its various composites for heavy metal removal for wastewater treatment have been elaborated on in this review. Several biosorbent based on nanocellulose such as aerogels, hydrogels, ion-exchange beds, flocculants, and photocatalyst to remove heavy metal toxicity have been discussed furthermore. Research work on the effect of composites of carbon nanotube, functionalized cellulose has been covered too.

https://link.springer.com/content/pdf/10.1007/s10924-021-02185-4.pdf

Amita Sharma

Papers

Commercial application of cellulose nano-composites - A review.

Process optimization for the production of cellulose nanocrystals from rice straw derived α-cellulose

Fabrication of cellulose acetate nanocomposite films with lignocelluosic nanofiber filler for superior effect on thermal, mechanical and optical properties

A Comprehensive Review on the Heavy Metal Removal for Water Remediation by the Application of Lignocellulosic Biomass-Derived Nanocellulose

Recent approaches for enhanced production of microbial polyhydroxybutyrate: Preparation of biocomposites and applications.