Blends freeze fracture

Figure 6. Scanning electron micrographs of freeze-fracture surfaces for injection molded (A), dioxane cast (B), and pyridine cast (C) blends at a composition of 15% lignin. (2000X) (From ref. 10, with permission of But-terworth ic Co., Ltd.)...

Figure 5 presents the results of tensile tests for the HPC/OSL blends prepared by solvent-casting and extrusion. All of the fabrication methods result in a tremendous increase in modulus up to a lignin content of ca. 15 wt.%. This can be attributed to the Tg elevation of the amorphous HPC/OSL phase leading to increasingly glassy response. Of particular interest is the tensile strength of these materials. As is shown, there is essentially no improvement in this parameter for the solvent cast blends, but a tremendous increase is observed for the injection molded blend. Qualitatively, this behavior is best modeled by the presence of oriented chains, or mesophase superstructure, dispersed in an amorphous matrix comprised of the compatible HPC/OSL component. The presence of this fibrous structure in the injection molded samples is confirmed by SEM analysis of the freeze-fracture surface (Figure 6). This structure is not present in the solvent cast blends, although evidence of globular domains remain in both of these blends appearing somewhat more coalesced in the pyridine cast material.

Figure 10. SEM photomicrograph of 65 -f 35 (St + BA) blend latex film (A) surface (B) freeze fracture section...

Neat polymers and their blends were studied In dynamic shear field (using RMS) and In constant shear stress field using Rheometrlc Stress Rheometer, RSR. The molecular parameters of polymers and blends were determined by Size Exclusion Chromatography in trichlorobenzene at 14O C. The morphology of freeze-fractured specimens was characterized In Scanning Electron Microscope, SEM, Jeol JSM-35CF. 

Morphology. The SEM of freeze-fractured System-1 specimens Indicates dispersed droplet morphology In blends containing 5, 75 and 95% PP... 

Figure 10.4. Micrograph of a freeze-fractured surface of an HDPE/PA-6 extruded blend, showing tree ring structures typical of telescopic flow in the capillary, caused by interlayer slip [Dumoulin et al., 1986].

Figure 7.10 SEM micrographs of freeze-fractured surface of PLA/NR (a) and PLA/NR-g-PVAC blends at different PVAc contents 1% (b), 5% (c) and 12% (d).

Figure 4 SEM photographs of fractured surfaces of PEI-TLCP blend fibers at the draw ratio of 1 (x 3000). The samples were fractured after freezing in liquid nitrogen. The amount of PEsl in the blends are (A) 0 phr, (B) 0.75 phr, (C) 1.5 phr, (D) 2.25 phr, (E) 3.75 phr, and (F) 7.5 phr. Source Ref. 11.

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