Surface-modified carbon nanofiber

The above polyolefin copolymers have also been used to prepare conventional composites and nanocomposites. However, similar to the case of polymer blends, not too many studies have been reported thus far. Recently, Kelarakis et al. (49) have mixed 10 wt% of surface-modified carbon nanofiber (MCNF) with propylene-ethylene random copolymer (propylene 84.3%). The MCNF acted as a nucleating agent for crystallization of the a-form of PP in the matrix. During deformation at room temperature, strain-induced crystallization took place, while the transformation from the 7-phase to a-phase also occurred for both unfilled and 10 wt% MCNF-filled samples. The tensile strength of the filled material was consistently higher than that of pure copolymer. These results are illustrated in Fig. 8.27. 

Chen, X.M., Yoon, K.W., Burger, C., Sics, I., Fang, D.F., Hsiao, B.S., Chu, B. / -situ X-ray scattering studies of a unique toughening mechanism in surface-modified carbon nanofiber/UHMWPE nanocomposite films , Macromolecules 38(9) (2005), 3883-3893... 

However, this disadvantage can be overcome by means of the surface modification of these electrodes with nanostructures, as the use of carbon nanotubes (CNTs) [10], or gold nanoparticles [11], since they improve the electronic transfer of the surface of the electrode, and improve the analj ical characteristics offered by the sensor. Carbon nanofibers can also be used to modify the electrodic surface in order to improve the analj ical characteristics of the transducer. 

Electrochemical sensors, modified with nanomaterial, have contributed to create great expectations in the last decade [4-8]. New materials such as carbon nanotubes [8-10], metal [3, 5, 11-16] and polymer nanoparticles [14, 17-20], carbon nanofibers [21-23], and boron-doped diamond nanograss [24] are ideal for electrochemical sensors due to their high surface area, high aspect ratio, and enhanced catalytic properties [25-30]. 

The thermal degradation behavior of nanoclay-modified epoxy has been studied, and is closely linked to the fire performance. Nanoclay has little effect on this behavior, and may even reduce the temperature at which degradation starts due to the relative instability of tbe surface treatment (Brnardic et al. 2008). The addition of carbon nanofibers to an amine-cured epoxy polymer had no effect on the decomposition temperature of epoxy (Zhou et al. 2007), but single-walled nanotubes have been shown to degrade the thermal stability (Puglia et al. 2003). 

Polymer nanocomposites represent a rapidly expanding research area. Nanocomposites refer to a class of reinforced polymer with a low percentage of well dispersed nanopartieles. These materials often demonstrate notable improvement in properties such as mechanic characteristics, tensile strength, heat and chemical resistance. Nanoparticles can be classified based on how many dimensions are on the nanoscale. The first type is plate-like (e.g. nanoclays) that has a thickness in the nanometer range and lateral dimensions in the sub-micron or micron range. Two types of nanoclay, 20A (Southern Clay) and MHABS (a surface modified clay 20A), are used in our research. The second type has two dimensions in the nanometer range, such as carbon nanofibers (CNF) or carbon nanotubes. The third type has three dimensions in the range of nanometer, such as spherical silica particles. The latter type of nanoparticle is not used in our study. 

Nanocable chemosensors have been formed in which an inner core fiber filament is further modified by polymerization of the conducting polymer on its surface. This was first described for sensing by Zhang et al. in which a carbon fiber was used as the template for the electrochemical polymerization of a thin film of PANI [27]. The resulting nanoelectrode sensor was used to detect changes in pH resulting from the level of protonation in the polymer backbone. PPy nanofibers have been formed by the electrospinning of nylon fibers. 

The synthetic mbber is widely used, this type of elastomer have important properties and numerous application due to stability. These properties are favored when the synthetic mbber is reinforced with organic nanoparticle as carbon nanombes, nanofibers, graphene, and fuUerene, among other [78-80]. These may or may not be modified nanofiUers surface for subsequent incorporation in the matrix, promoting greater interaction between inorganic nanofillers and polymeric matrix, thus improving the thermal stability of the nanocomposite etc. [81, 82]. 

---