DIELECTRIC BEHAVIOR OF EPOXY AND POLYESTER LAMINATES IN MOISTURE AND ELECTRONIC PACKAGING EXHALATES

The dielectric behaviour of epoxy and polyester laminates has been studied before and after exposing the samples to moisture (relative humidity 60 to 95%) and various exhalates (HCl, HNO//3, HCOOH, CH//3COOH, NH//3 and SO//2 vapours) which are normally released by electronic packaging materials. A strong dielectric dispersion at room temperature was observed. The dissipation factor also increases appreciably, the increase being higher at higher exposure times. The results have been explained in terms of the ionic conductivity due to dissociation of the exhalates. The changes were reversible except in the case of HCOOH and CH//3COOH for epoxy and NH//3 for polyester. The results indicate some chemical changes in these cases.