Thermogravimetry of the thermal degradation of Japanese lacquer (urushi) films

The kinetics of the thermal degradation of Japanese lacquer (urushi) films in N 2 and in air were studied by means of thermogravimetry (TG). Thermogravimetric and derivative thermogravimetric curves indicated that the degradation occurred in three stages. The atmosphere influenced the apparent activation energies ( E a ) of the three degradation stages. The activation energies ( E a ) for the first stage in N 2 and air, obtained from the TG curve, were 19.12 and 10.19 kcal mol −1 , respectively, and the corresponding pre-exponential factors ( A ) were 6.18 × 10 5 and 1.24 × 10 2 min −1 for 1-year-old urushi films.