Fibers nanosized

If cellulosics such as BC are composed of nanosized fibers and the nanofiber structuring determines the product properties, these polymers are described as nanocelluloses. 

Moreover, the nanosized fibers of the swollen nanocelluloses can be coated with different components and the pore system can be loaded with agents (post-modification). Further methods in this field use well-known procedures... 

Figure 12.16 illustrates how Raman microspectrometry can be used to image nanophase distribution in nanosized materials. We will present the case of SiC fibers for aerospace applications, prepared with different technologies. These... 

Procter Gamble [281] has developed very recently a network of nanosized fibers containing chitosan and claimed that this composition would be useful in many areas, including hair care, skin care, oral care, water treatment, and drug delivery. 

Figure 2. Adsorption-desorption isotherms of benzene vapors by nanosized fibrous alumina annealed at temperatures 750 (1), 900 (2) and 1100 °C (3) - A and an image of alumina fiber (900 °C) - B.

Tetrabutyl titanate was used as a sol-gel precursor of a nanosized Ti02 coating of aramid fibers. The photostability of the aramid fiber increased by this treatment." ... 

Figure 3.71 shows the change of average polystyrene phase diameter versus distance along the radial direction. The gradient phase structure was intensely related to the polystyrene content. With increasing amount of polystyrene, the size of the dispersed phase in the fiber center decreased continuously to nanosized fibrillar structure [257]. 

It has also been reported that polypropylene modified with nanosized silicon oxide can distinctively improve the processability of polypropylene while simultaneously increasing its strength. On the basis of the four property indices, specific electrical resistance, water absorption, flex stiffness, and rigidity, the modified fiber has reached or surpassed the indices of polyamide 6. 

Nanomaterials represent today s cutting edge in the development of novel advanced materials, which promise tailor-made functionality for unique applications in all important industrial sectors. Nanomaterials can be clusters of atoms, grains 100 nm in size, fibers that are less than 100 nm in diameter, films that are less than 100 nm in thickness, nanoholes, and composites that are a combination of these. In other words, it implies that the microstructures (crystallites, crystal boundaries) are nanoscale [1]. Nanomaterials include atom clusters, nanoparticles, nanotubes, nanorods, nanowires, nanobelts, nanofilms, compact nanostructured bulk materials, and nanoporous materials [2]. Materials in nanosize range exhibit... 

The infiuence of supported Au particles on the photoconversion of NO2 has been investigated by simultaneous detection of gas phase and surface species using DRIFTS by Ramakrishnan et al. [24]. The nanosized Au-supported catalyst was prepared by deposition of pre-prepared Au nanoparticle precursor solution onto titania. The catalysts were illuminated in the in situ reaction chamber by a 365 nm 50 mW LED UV source coupled with fiber optics while simultaneously collecting the diffuse reflectance spectra. Adsorption of NO2 is negligible in dark however, new absorption bands arose between 1200 and 1800 cm after starting illumination of the catalyst (Figure 4.1). The band intensities observed with Au-supported catalysts increase markedly with N O2 photocatalytic conversion in the quadrupled gas phase. Marked increase of activity has also been confirmed for the photooxidation of phenol in parallel batch experiments. 

Nanocomposites refer to the combination of nanosized fillers (10 m diameter) with polymers, rather than the combination of polymer matrix (filled with nanoparticles) and fiber reinforcement The most popular fillers used as fire retardants are layered silicates. Loading of 10% or less (by weight) of such fillers significantly reduces peak heat release rates and facilitates greater char production [7]. The char layer provides a shielding effect for the composites below and the creation of char also reduces the toxicity of the combustion products, as less carbon is available to form the CO and CO2. 

With this technique the possibility of the production of different morphologies was suggested, that is, smooth and porous fibers as well as beaded fibers. Moreover, pol5miers such as PLA, PMMA, PEO, PS, and PVC have been used to produce micro- and nanosized fibers with diameters as low as 40 nm. 

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