The kinetics of thermal degradation for polydimethylsiloxane(Si-O- 1)

polydimethylsiloxane containing residual basic catalyst(Si-O-2)

silicone gums containing cyclodisilaZane (St-N-1)

Si-O-3 by incorporation of Si-N-1 into Si-O-1 and Si-O-4 by incorporation of Si-N-1 into St-O-2 were studied by the isothermal gravimetric analyses (IGA) in nitrogen atmosphere. The results indicated that Si-N-1 has outstanding thermal stability. The activation energy of degradation is 344kJ /mol. Si-O-1 undergoes the thermal degradation with the activation energy of 152kJ/mol

while the activation energy of degradation energy for Si-O-3 is 230 kJ/mol in presence of Si-N-1.The activation energy of degradation for Si-O-4 is 144 kJ/mol

while Si-O-2 has only 62 kJ/mol in absence of Si-N-1.The enhancement of thermal stability for Si-O-4 is attributed to decreasing the loose ability of the catalyst ion pair when Si-N-1 removes the SiOH groups and water in the Si-O-4.