Influence of Different Organic Side Groups on the Thermal Behavior ofPolyphosphazenes: Random Chain Cleavage, Depolymerization, and Pyrolytic Cross-Linking

摘要

The thermal behavior of several polyphosphazenes was examined. The polymers werestudied by thermogravimetric analysis between 50 and 100 C, by bulk pyrolysis in a tube furnace over the same temperature range, and by thermolysis in a closed system. The volatile products were analyzed by a combination of P NMR spectroscopy, vapor-phase chromatography, and mass spectrometry. Three distinct processes were identified: (1) random chain cleavage of the phosphazene backbone, (2) depolymerization to form small molecule cyclic phosphazenes, and (3) cross-linking reactions to form a network structure. Keywords: Phosphazenes, Polymers, Polyphosphazenes, Thermolysis, Ceramics, Depolymerization. (JS)