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Nucleation nanocomposites

Nanoclay particles by virtue of their particulate nature are emerging as effective heterogeneous nucleating agents for polyesters. The nanoclay particles in PET/montmorillonite nanocomposites impart to PET a higher crystallization rate without the need for expensive nucleating agents. [Pg.519]

At co-deposition of dielectric and M/SC the structure of a nanocomposite film depends on a relationship between the rate of formation of M/SC particles and the rate of making of a solid dielectric matrix. Models of such deposition are discussed. The special attention is paid to new low-temperature processes of nucleating and growth of nanoparticles in a solid polymeric matrix containing the inclusions of... [Pg.571]

Figure 38 shows the XRD pattern (a) and hysteresis loop (b) of FePt C double-layered nanocomposite thin-film medium. The soft underlayer FeCoNi (111) peak and the Zl0 FePt (001) and (002) peaks are shown only in the XRD pattern. This means that the preferred crystal orientation of Tl0 FePt C nanocomposite film is successfully obtained on this SUL by nonepitaxial growth. The polar-Kerr measurement shows a square loop that is only sensitive to the top layer the Kerr effect data shown in this loop give the coercivity Hc = 8.5 kOe, nucleation field Hn = 5.65 kOe, remanence ratio S = 1, and loop slope ( at Hc) a = 3.3, respectively. [Pg.235]

Giraldo et al. (38) reported polyamide 6 nanocomposites in which the crystallization temperature of the polymer was observed to increase with the addition of 2 wt% CNTs. The temperature was 185°C for the pure polyamide which subsequently increased to 190 °C. The authors suggested that the nanotubes might serve as the nucleation sites for the polymer crystals to grow which was also confirmed by the reduction of the chain mobility by dynamic mechanical analysis. The thermal stability of the composites was reported to enhance after the incorporation of nanotubes. [Pg.36]

Applications. Numerous uses of x-ray analysis were reported for filled systems. They include orientation of talc particles in extruded thennoplastics, particle size deteimination in nanocomposites, crystallinity of talc nucleated PP, crystallinity of polymerization filled PE, diffraction pattern of filled PVA, structure of nanocomposites based on montmorillonite, degree of filler mixing, structural characteristics of fillers, structure of carbon black filled rubber, the effect of apatite concentration on the structure of wood pulp, and graphite as template. " This list shows the versatility of the method in applications to filled systems. [Pg.598]

The crystallisation behaviour of PA-6/MMT nanocomposites is complicated to analyse because its polymorphic nature produces a monoclinic a and psuedohexagonal y structure, both of which are affected by the presence of clay particles in the matrix (9). The clay particles themselves have been shown to act as nucleating agents, increasing the crystallisation process in some instances while retarding crystal growth in others. Clearly, the cause of these phenomena must be understood so some measure of control can be employed to produce useful nanocomposite materials with desired properties. [Pg.262]

As summarized in Table 1, hollow Si02 nanocomposites could be formed only in the cases of ammine complex precursors, and non-hollow ones were formed in the cases of chloride precursors. The nucleation and crystal growth of metal ammine complexes in the reversed micelle may be responsible for the... [Pg.65]

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. [Pg.220]


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