Physico-chemical modifications of superficial regions of low-density polyethylene (LDPE) film under corona discharge

Using e.s.r., ATR and d.s.c., data on the chemical and structural superficial modifications of LDPE films under corona discharge in the presence of air have been obtained. The results show that the electrical discharge creates superficial ethylenic bonds (1630 cm −1) and carbonyl groups (1720 cm −1), the amount of which varies inversely with the main power supply. The treated samples when stored in the presence of light and air undergo marked structural and chemical changes. Formation of a thin waxy layer rich in 〉 CO and 〉 CC 〈 bonds with almost total absence of CH 2CH 2 groups characteristic of LDPE is observed.