Globular disperse structures models

FIGURE 3.17 Models describing 2D (a) and 3D (b) globular disperse structures. (From Shchukin, E.D., Physical-chemical theory of the strength of disperse structures and materials, in Physical-Chemical Mechanics of Natural Disperse Systems, E.D. Shchukin, N.V. Pertsov, V.I. Osipov, and R.I. Zlochevskaya (eds.), Izd. MGU, Moscow, Russia, 1985, pp. 72-90.)... 

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.

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