Poly silanes temperature effects

The recent interest in substituted silane polymers has resulted in a number of theoretical (15-19) and spectroscopic (19-21) studies. Most of the theoretical studies have assumed an all-trans planar zig-zag backbone conformation for computational simplicity. However, early PES studies of a number of short chain silicon catenates strongly suggested that the electronic properties may also depend on the conformation of the silicon backbone (22). This was recently confirmed by spectroscopic studies of poly(di-n-hexylsilane) in the solid state (23-26). Complementary studies in solution have suggested that conformational changes in the polysilane backbone may also be responsible for the unusual thermochromic behavior of many derivatives (27,28). In order to avoid the additional complexities associated with this thermochromism and possible aggregation effects at low temperatures, we have limited this report to polymer solutions at room temperature. 

The cloud point curves for unfilled poly(vinyl acetate) - poly(me-thyl methacrylate) mixtures and those filled with 10% of non-modified and silanized fumed silica show that curves for filled mixtures are situated at much lower temperature than those for unfilled material.It should be noted that the temperature of phase separation decreases sharply in the region where one alloy component has a predominant content. The addition of silane-treated fumed silica also results in a lower temperatures of phase separation. These effects were attributed to the difference in adsorption of both components at the interface with a solid and are connected with the asymmetry of interaction in the system. The phase separation temperature in this alloy also depends on the filler content (Figure 7.4). At the same time, the phase separation temperature depends on the ratio of components. This fact may be interpreted as indirect confirmation of the role of asymmetry of interactions, because increasing the filler content should affect the as5mimetry of the interactions and therefore have an... 

Campbell and co-workers [23] studied the effect of a silyl peroxide on the compati-bilization of polysiloxane/poly(vinylidenefluoride-co-hexafluoropropylene) (PVDFHFP) blend. The peroxide used, vinyltris(t-butyl peroxy)silane, was specially synthesized in laboratory. The typical decomposition temperature of this peroxide was 150 °C, as measured by DSC. The kinetics of the decomposition reaction of this peroxide were not reported. 

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