Dispersed morphologies

As shown in Fig. IIB, dispersion morphology for the nylon 6/Vectra B/SA-g-EPDM blend was totally different from that of the PBT-Vectra A-SA-g-EPDM blend. TLCP phases were very uniformly and finely dispersed in the nylon 6-Vectra B-SA-g-EPDM blend and a large fibril shape observed in the PBT-Vectra A-SA-g-EPDM blend could not be seen under polarized microscope. It should be noted that the size of the dispersed TLCP phase is very small (submicron size). This small size of the TLCP phase in the nylon 6/elastomer matrix was not observed by any others [4,54,55,58]. A closer look by SEM more clearly revealed the dispersion of Vectra B in the matrix (Fig. 12B). TLCP phases are very... 

Figure 18. Different stages of the spinodal decomposition in an asymmetric mixture (0 = 0.5) t is the dimensionless time. The Euler characteristic is initially negative, which indicates that morphology is bicontinuous. After a certain time the Euler characteristic becomes positive, which indicates that the transition to dispersed morphology occurred. For a dispersed morphology the Euler characteristic equals twice the droplet number.

A blend between two highly immiscible polymers, 20% PDMS in Nylon 6 (PA6) has a very thin interphase thickness of 2A, as shown on Table 11.1, and, as a result a coarse dispersed morphology of about 10pm. Similarly coarse morphology in obtained when PDMS is blended with PA 6 amine-functionalized at each chain end to form PA 6/diamine. 

Fig. 11.41 Evolution of the dispersed morphology along the TSMEE mixing element at three operating conditions of the weak matrix Blend 1 (a) 140°C and 60rpm (b) 140°C and 120 rpm (c) 180°C and 120 rpm. [Reprinted by permission from the Proceedings of the Thirteenth Semi-annual Meeting of the Polymer Mixing Study, Polymer Processing Institute, Hoboken, NJ (1996).]...

Blends 3 (a,b,c) Rheologically Robust Matrix and Weak Dispersed Components Since PE 1409 is a low viscosity nearly Newtonian polymer melt, its dispersive behavior is uncomplicated and more Newtonian like. Blend 3a forms a small (3-5-pm) droplet dispersion morphology, and Blend 3b is even finer (1-2 pm), becoming, only below 2% concentration, less subject to flow-induced coalescence. The TSMEE-obtained dispersions are finer than those from the TSMEE, with a variety of kneading elements (126). What is noteworthy about these blends is the early stages of the dispersion process, shown on Fig. 11.44, obtained with Blend 3a using the TSMEE at 180°C and 120 rpm. 

The dispersion morphology of prepared materials was studied with a multitechnique approach, by means of rheology, scanning electron microscopy (SEM), x-ray diffraction (XRD), and nuclear magnetic resonance (NMR). The results of these tests showed that the so formulated PA6 nanocomposites used in the present study are fully exfoliated [1,2],... 

We review the research on preparation, morphology, especially physical properties and applications of polyurethane (PU)/carbon nanotube (CNT) nanocomposites. First, we provide a brief introduction about the preparation of PU/CNT nanocomposites. Then, the functionalization and the dispersion morphology of CNTs as well as the structures of the nanocomposites are also introduced. After that, we discuss in detail the effects of carbon nanotubes on the physical properties (including mechanical, thermal, electrical, rheological and other properties) of PU/CNT nanocomposites. The potential applications of these nanocomposites are also addressed. Finally, the challenges and the research that needs to be done in the future for achieving high-performance polyurethane/carbon nanotube nanocomposites are prospected. 

Functionalization, Dispersion Morphology and Micro-/Nano-structures... 

More field tests will be needed, especially to incorporate research advances in such areas as materials design phase behavior and dispersion morphology mechanisms of dispersion formation, flow, and breakdown and simulation of dispersion-based sweep control. 

The phase-separated droplet/matrix morphology is an outcome of the nucleation and growth mechanism (NG) of phase separation. The phase dimensions are similar to those observed for SD, but in this case the properties are dominated by the matrix polymer with the dispersed phase playing the role of a compatlblllzed filler. A similar dispersed morphology, but with large drops, can be obtained by allowing the SD or NG system to ripen. The coarsening usually leads to a non-uniformity of properties. 

DRS measurements support the TPR results. The impregnated catalysts and steam treated (IMPV) did not show the presence of V after the reduction. Probably, the hydrogen consumption in the TPR profile is due to the reduction of cerium. The band in the d-d transition can be attributed to the formation of alloys like cerium vanadate, according to the literature [14]. Baugis et al. [15] reported that the presence of vanadate with rare earth decreases the diffusion of vanadium in the zeolite structure [14]. The existence of these compounds may affect the oxidation state, the dispersion, morphology and location of cerium species in the catalyst. 

Sometimes coincident crystallization occurs in finely dispersed morphology... 

PSF/PET blends show a dispersed morphology. The combination of crystalline PET and amorphous polysulfone provides chemical resistance and warp-free properties. The amount of crystalline polymer is varied to meet requirements in thermal properties and the level of reinforcement is varied to tailor the modulus. The blends have electrical and mechanical properties similar to PET but only a third of its shrinkage and warpage. Also, stress crack resistance to common solvents is improved. Similarly, the service T is upgraded compared to PET. The blends are formed by injection molding and extrusion. 

NBR/PVC blends marketed by Uniroyal Parac-riP OZO) cover the concentration range NBR/PVC = 70 30 to 60 40 and show a dispersed morphology. They are typically formed by injection molding, extrusion and calendering and show the good fuel and oil resistance and low compression set. 

However the impact properties of the lamellar blends were lower than that obtained for dispersed morphology. 

For Oleflex TPO (PP and PE with a-olefin random copolymer), reactive processing (cross-linking) is used to get a finely dispersed morphology of copolymer dispersed in the polyolefin matrix. Recommended processing conditions are similar to those for neat PP or PE. For calendering, the melt temperature should be in the range 165-175°C. 

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