Page 679 - Handbook of Thermal Analysis of Construction Materials

646 Chapter 16 - Paints and Coatings

heterogeneous chemical environment. Sample B had a low amount of cross-
linker and the lowest catalyst content. It was possible that it contained
heterogeneous regions of low and high cross-link densities responsible for
the two lowest peaks. The peak at -96°C was due to recrystallization. The
well-cured sample (C) showed only one major transition at about -116°C,
attributed to high amounts of amorphous and high cross-link density
material.

Figure 10. Temperature dependence of tan δ for release coating samples with different
levels of cure. (Reprinted with permission.) [21]

The recrystallization behavior of the samples was confirmed by
DSC. Figure 11 shows the DSC curves for samples A–C. Sample C shows
the highest T and no detectable recrystallyzation. Samples A and B display
g
not only well-defined recrystallization peaks but also melting endotherms
not observed in Sample C. From the results of the study, it was concluded
that the DSC and DMA methods can be used for monitoring the cure levels
in the silicone release coatings. [8]