Thermal decomposition of tetrazole-containing polymers. IV: poly-1-vinyl-5-methyltetrazole and poly-1-vinyl-5-phenyltetrazole

The thermal decomposition of poly-1-vinyl-5-methyltetrazole (P-1VMT) and poly-1-vinyl-5-phenyltetrazole (P-1VPT) was studied by high resolution thermogravimetry (HRTG) differential scanning calorimetry (DSC) and thermal volatilization analysis (TVA). Solid residues, high boiling products, and gases were collected at different stages of the thermal decomposition and identified by FTIR and/or GC-MS. Both P-1VMT and P-1VPT show complex multistep decomposition on progressive heating. The thermal decomposition starts from degradation of tetrazole pendant groups. At the beginning, P-1VMT presumably eliminates acetonitrile, whereas P-1VPT eliminates nitrogen. On further heating, the partially decomposed polymers melt and an evolution of the pendant groups (5-methyltetrazole and 5-phenyltetrazole) is observed. Thermal fragmentation of the polymeric chain occurs at high temperatures (≥320°C).