Cellulose composite nanofibers

Nanofibers and webs are capable of delivering medicines directly to internal tissues. Anti-adhesion materials made of cellulose are already available from companies such as Johnson Johnson and Genzyme Corporation [19]. Namekawa etal. [20] developed a zeolite-polymer composite nanofiber mesh to remove uremic toxins for blood purification. The nanofiber is composed of blood compatible poly(ethylene-co-vinyl alcohol) (EVOH) as the primary matrix polymer and zeolites which are capable of selectively adsorbing uremic toxins such as creatinine. It was suggested that the proposed composite fibers have the potential to be utilized as a new approach to removing nitrogenous waste products from the bloodstream without the requirement of specialized equipment [21]. Kidney failure patients can have an alternative to dialysis in the form of nanofiber mesh which is portable and wearable. 

Cellulose is the most abundant biopolymer on earth. It can be used in different applications, namely in the form of fibers, and cellulose can be converted into numerous cellulose derivatives. Cellulose micro- and nanofibers have been the subject of intense research in the field of composites. Cellulose derivatives can show liquid crystalline chiral nematic phases, which can be used for the production of diverse composite systems. All-cellulosic composites based on liquid crystalline cellulosic matrices reinforced by cellulose micro- and nanofibers can show enhanced mechanical properties due to fiber orientation induced by the liquid crystalline matrix. Cellulose-based fibers electrospun from liquid crystalline phases can develop different structures, which are able to mimic the shape of plant tendrils on the nano- and microscale, opening new horizons for ceDulosic membrane applications. 

Han SO, Youk JH, Min KD, Kang YO, Park WH. Electrospinning of cellulose acetate nanofibers using a mixed solvent of acetic acid/water effects of solvent composition on the fiber diameter. Mater Lett 2008 62 759-62. 

Cellulose nanofiber reinforced polybutylene succinate (PBS) composites were fabricated by molding pulverized PBS powder and electrospim cellulose acetate nanofibers in the form of alternating stacked layers [125]. The fiber-reinforced composite had a higher storage modulus than PBS matrix without reinforcement in the temperature range Ifom -100 to 100°C. However, it was noticed that the crystallinity of the cellulose nanofibers was lower... 

Tang, C., Chen, P. Liu, H. (2008). Cocontinuous cellulose acetate/polyurethane composite nanofiber fabricated through electrospinning. Polymer Engineering and... 

These specific parameters are caused by the subsequently outlined biosynthetic formation of the BC and the resulting particular supramolecular structure as a network of nanofibers formed during self-assembly of the cellulose molecules in the aqueous culture medium, free from potential composite partners as in wood biosynthesis, reviewed in [1],... 

The second chapter by Dieter Klemm, Dieter Schumann, Hans-Peter Schmauder, and coworkers focuses on the recent knowledge of cellulosics characterized by a property-determining supramolecular nanofiber structure. Topics in this interdisciplinary contribution are the types of nanocelluloses and their use in technical membranes and composites as well as in the development of medical devices, in veterinary medicine, and in cosmetics. 

Iwatake, A., Nogi, M., Yano, H., Cellulose nanofiber-reinforced polylactic acid. Composites Science and Technology. 9, 2103-2106 (2008), DOI http //dx.doi.0rg/lO.lOl6/j.compscitech.2008.03.006. 

High-tenacity fibers have been demonstrated by dry-jet wet-spinning of anisotropic solutions of cellulose triacetate, but a product has not yet been commercialized [113,114], Nanofiber composites have been demonstrated by electro-spinning dilute cellulose acetate and triacetate solutions. These composites have exceptionally high specific surface area, and exciting new applications are envisioned [115], There are many new specialty applications, and research is continually finding new applications that take advantage of the unique balance of properties of cellulose acetate [107,109,110,116],... 

Ifuku, S., Nogi, M., Abe, K, Handa, K., Nakatsubo, F., Yano, H. Surface modification of bacterial cellulose nanofibers for property enhancement of optically transparent composites dependence on acetyl-group DS. Biomacromolecules 8, 1973-1978 (2007)... 

Fig. 2.5 ESEM micrograph of a bacterial cellulose-com starch composite. Arrows show bacterial cellulose nanofibers [12]...

Cellulose nanofibers from different sources have showed remarkable characteristics as reinforcement material for optically transparent composites [160, 161], Iwamoto et al. [160] prepared optically transparent composites of transparent acrylic resin reinforced with cellulose nanofibers extracted from wood pulp fibers by fibrillation process. They showed that cellulose nanofiber-reinforced composites are able to retain the transparency of the matrix resin even at high fiber content (up to70 % wt). The aggregation of cellulose nanofibers also contributes to a significant improvement in the thermal expansion properties of plastics. 

Peresin, M.S., Habibi, Y., Zoppe, J.O., Pawlak, J.J., Rojas, O.J. Nanofiber composites of polyvinyl alcohol and cellulose nanocrystals manufacture and characterization. 

Composites of natural cellulosic fibers may have the best option to the array because the nanofibers can interact with other natural materials to form highly ordered structures. The cellulose microlibrils have hydroxyl groups (OH) on their surface, which can form covalent bonds with the matrix. In literature, three alternative routes for the preparation of composites of cellulose are known [40]. The first route refers to the incorporation of hydrophobic libers in matrices such as polyethylene, polypropylene and polystyrene. In this case, it is necessary to a chemical or physical treatment, so that the surfaces of the matrix and the libers... 

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