Nanocellulose

International audienceNowadays, the incremental demands on utilization of renewable biomass has emphasize the importance of cellulosic materials. This can be justified by the large number of publications as well as the new generation of materials made from biosource residues. Cellulosic fibers present many potential advantages: the most important of them are their bio-renewable character, their ubiquitous availability in a variety of sources, and their low cost. This chapter presents a general overview of the preparation and characterization of nanocellulose from various sources. These products have recently acknowledged considerable attention as a potential source to produce nanomaterials with higher excellent performances. The preparation and characterization of cellulose nanocrystals (CNC), nanofibrillated cellulose (CNF), and bacterial nanocellulose (BNC) were discussed

Microscopic Techniques for the Analysis of Micro and Nanostructures of Biopolymers and Their Derivatives

Natural biopolymers, a class of materials extracted from renewable sources, is garnering interest due to growing concerns over environmental safety; biopolymers have the advantage of biocompatibility and biodegradability, an imperative requirement. The synthesis of nanoparticles and nanofibers from biopolymers provides a green platform relative to the conventional methods that use hazardous chemicals. However, it is challenging to characterize these nanoparticles and fibers due to the variation in size, shape, and morphology. In order to evaluate these properties, microscopic techniques such as optical microscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) are essential. With the advent of new biopolymer systems, it is necessary to obtain insights into the fundamental structures of these systems to determine their structural, physical, and morphological properties, which play a vital role in defining their performance and applications. Microscopic techniques perform a decisive role in revealing intricate details, which assists in the appraisal of microstructure, surface morphology, chemical composition, and interfacial properties. This review highlights the significance of various microscopic techniques incorporating the literature details that help characterize biopolymers and their derivatives

Gum Kondagogu/Reduced Graphene Oxide Framed Platinum Nanoparticles and Their Catalytic Role

This study investigates an environmentally benign approach to generate platinum nanoparticles (Pt NP) supported on the reduced graphene oxide (RGO) by non-edible gum waste of gum kondagogu (GK). The reaction adheres to the green chemistry approach by using an aqueous medium and a nontoxic natural reductant-GK-whose abundant hydroxyl groups facilitate in the reduction process of platinum salt and helps as well in the homogenous distribution of ensued Pt NP on RGO sheets. Scanning Electron Microscopy (SEM) confirmed the formation of kondagogu gum/reduced graphene oxide framed spherical platinum nanoparticles (RGO-Pt) with an average particle size of 3.3 ± 0.6 nm, as affirmed by Transmission Electron Microscopy (TEM). X-ray Diffraction (XRD) results indicated that the Pt NPs formed are crystalline with a face-centered cubic structure, while morphological analysis by XRD and Raman spectroscopy revealed a simultaneous reduction of GO and Pt. The hydrogenation of 4-nitrophenol could be accomplished in the superior catalytic performance of RGO-Pt. The current strategy emphasizes a simple, fast and environmentally benign technique to generate low-cost gum waste supported nanoparticles with a commendable catalytic activity that can be exploited in environmental applications

Tree Gum-Graphene Oxide Nanocomposite Films as Gas Barriers

To reduce the dependency on petro-based conventional plastics, research focusing on bioplastics derived from biological origin has gained precedence. Herein, we report an ecofriendly and a facile synthetic route to develop a freestanding nanocomposite film prepared from the combination of nonedible biodegradable tree gum waste and graphene oxide (GO). Three variants of bionanocomposite films such as GO-gum arabic (GA-GO), GO-gum karaya (GK-GO), and GO- kondagogu gum (KG-GO) were fabricated via solution casting of respective gums with GO (0.5% and 1.0%) in an aqueous environment. GO was thoroughly blended within different types of gum matrices via the hydrogen bond interaction and electrostatic attraction, thus forming interconnected homogeneous GO-gum layered structure. Morphological analysis revealed a natural nacre-like structure comprised of gum-intercalated graphene sheets, which was further confirmed by X-ray diffraction studies. The addition of GO further transformed the brittle gum film into a freestanding film with substantial mechanical strength. Furthermore, the layered nanocomposite films demonstrated enhanced oxygen gas barrier property as well as reduced water vapor transmittance. The barrier properties are comparable to the plastics traditionally used in packaging, emphasizing the potential of tree gums nanocomposite films in packaging applications. Such frugally viable gums can be a cost-effective alternative in the development of nanocomposite films that could be readily used for applications in food packaging, pharmaceutical, and various biomedical industries