Effects of photo-oxidation on tensile deformation behaviour in low-density polyethylene

Quenched low-density polyethylene (LDPE) films were photo-oxidized with a xenon arc lamp at 63 degrees C for 12 days. The effects of photo-oxidation on the deformation behaviour of LDPE films were investigated by a rheo-optical method in which IR dichroism was examined under uniaxial extension. The orientations of the oxidized segments introduced by photo-irradiation as well as of LDPE crystals were measured simultaneously with tensile deformation. The crystalline parts dominate the deformation before yielding but the orientation of oxidized segments gradually increases after yielding and has a maximum just before the break point.