engleski

Thermally stimulated discharge of blends of Novolac phenol-formaldehyde resin and nylon-6

Thermally stimulated depolarization current studies of Novolac phenol-formaldehyde (NPF) resin mixed with 10 wt% and 20 wt% nylon-6 (Ny6) were performed in the temperature range 300 to 350 K using various poling fields, Ep, and various poling temperatures, Tp. Experiments carried out with direct contacts show only a dipolar relaxation peak P1 at Tm1 = 337 K. By reversing Ep, in addition to P1, a space charge relaxation peak P2 is observed at Tm2 = 345 K. By performing experiments at different Tps with one electrode blocked with Teflon foil, it is possible to suppress the background current, which then allows one to separate and to identify the two relaxation processes. Addition of Ny6 to a NPF matrix increases the total depolarization current and causes electrode polarization due to the increase in heterogeneity of the blend. Ny6 also increases the maximum temperature of the two peaks but it decreases the activation energy of the dipolar relaxation process. These effects are attributed to the hydrogen bonding between functional groups from the matrix and nylon-6.

thermally stimulated current ; phenol-formaldehyde novolac resin

nije evidentirano