Fig. 1.

Low voltage scanning electron microscopy LVSEM (JEOL 6320FV low-voltage microscope operating at 1 kV) images of permanganic acid etched freeze fracture surfaces coated with a gold–palladium layer (10 nm thickness) of four polyethylenes obtained with different pressure and thermal treatments. The following polyethyelenes were studied: (1) untreated control (PE) (2) high-pressure crystallized, uncrosslinked polyethylene (HP-PE), (3) 50 kGy gamma radiation crosslinked polyethylene (XPE), and (4) high-pressure crystallized, 50 kGy gamma radiation crosslinked polyethylene (HP-XPE).³⁶