As one of the potential alternatives of SF6 gas which produces a remarkable greenhouse effect

CO2 gashas been adopted by circuit breaker as insulation and arc-extinguishing medium. In fact

PTFE vapor resulting fromnozzle ablation may modify fundamental properties of plasma

which then has an effect on interruption performanceof circuit breaker. The determination of plasma fundamental properties is the prerequisite to arc physical modeling es-tablishment and interruption performance optimization for circuit breaker. Thus

this paper investigates the funda-mental properties of CO2-PTFE thermal plasma for the temperature range 300-30

000 K under 0.6 MPa. First

Gibbs free energy minimization method is utilized to determine plasma equilibrium composition which then uses todetermine thermodynamic properties with standard thermodynamic equations. Finally

transport coefficients（electri-cal conductivity

thermal conductivity and viscosity）for CO2-PTFE plasma is calculated based on Chapman-Enskogtheory. It can be observed that PTFE modifies plasma fundamental properties. More specifically

PTFE results in adramatic influence on viscosity

thermal conductivity and electrical conductivity at low temperature for CO2-PTFEthermal plasma and the influence of PTFE with a small proportion（less than 25%）on electrical conductivity is limited.