DIELECTRIC-PROPERTIES OF ORIENTAL LACQUER COATING NETWORK

In order to study the dielectric properties of the oriental lacquer fi lms, three different films have been prepared differing purification a nd curing procedures. Dielectric properties were measured in the frequ ency range of 1 Hz to 10(5) Hz at various temperatures between -50 deg rees C and 150 degrees C. The DEA using 1 Hz showed that glass transit ion and secondary relaxation temperatures of oriental lacquer film are very time dependent. In addition, the frequency-independent negative peak between 25 degrees C and 45 degrees C was observed, which could r epresent the formation of crosslink by laccase enzyme during heating. On the contrary, the high temperature cured film showed a hardly notic eable negative peak at the temperature range. The relationship between thermodynamic properties and chemical structures has been discussed b ased on the analysis of the dielectric relaxation behavior using the C ole-Cole plot and the dielectric relaxation intensity.