Cellulose nanofibers applications

Biodegradable polyester-based composites have been extensively studied for use in medical applications owing to their biocompatible and degradable properties in the human body. The major reported examples in biomedical products are fracture-fixation devices, such as sutures, screws, micro titration plates, and delivery systems [77]. Cellulosic nanofiber reinforced PLA composite materials... 

In a novel application of BC, Grande et al. (2009) added starch to the culture medium of cellulose-producing bacteria in order to introduce the granules into the forming network of cellulose which allowed the preservation of the natural ordered structure of cellulose nanofibers. Microscopic analysis revealed that starch acted as a matrix which filled the voids in the BC network. Using MCF as reinforcement, the nanocomposites showed considerable improvement in mechanical properties. 

Nanocomposite describes a two-phase material where one of the phases has at least one dimension in the nanometer range (1-100 nm). They differ from conventional composites by the exceptionally high surface-to-volume ratio of the reinforcing phase and/ or its exceptionally high aspect ratio. The reinforcing material can be made up of particles (e.g., minerals), sheets (e.g., exfoliated clay stacks) or fibers (e.g., carbon nanotubes, electrospun fibers or cellulose nanofibers). Large reinforcement surface area means that a relatively small amount of nanoscale reinforcement can have an observable effect on the macroscale properties of the composite. There has been enormous interest in the commercialization of nanocomposites for a variety of applications, and a number of... 

Apart from the production process of NFC by homogenization, their final application is a critical issue. Because of the hydrophilic nature of cellulose nanofibers, their incorporation and dispersion with common polymers, which are hydrophobic, are very critical issues [38]. Low interfacial adhesion between these two parts in composite leads to reduction in the mechanical and other properties of the final product. Thus, a wide variety of modifications like carboxymethylation [65], 2,2,6,6-tetramethylpiperdine-1-oxyl (TEMPO) oxidation [66, 67], acetylation [68, 69], and silylation [70, 71] have been designed to overcome this problem. The modification strategies of cellulose nanosize materials are discussed in Section 11.6. 

CeO nanoparticles were attached to the surface of the nanofiber substrate due to the strong interfacial and electrostatic interactions between the carboxylic or hydroxyl groups of the cellulose nanofiber and the CeO nanoparticles, which is effectively prevented nanoparticle fall-off. Compared to the natural cotton cellulose nanofibers, the modified natural cotton cellulose nanofibers by hydrothermal incorporation of CeOj nanoparticles showed excellent protection against UV radiation because of the function of the CeO particles. This functional nanofiber will have potential applications in various areas, such as the medical, military, biological, and optoelectronic industrial fields including UV protection for data storage or memory devices, in the future. 

In the case of potential applications, these particular dimensions affect the final structure and properties of the fabricated products. According to different terms of nanocelluloses, these can be divided into two basic categories (a) cellulose nanofibers (CNFs) and (b) cellulose nanocrystals (CNCs). Morphology (TEM images) of CNFs and CNCs is shown in Figure 15.3. 

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