Infrared and low-frequency Raman data evidence the presence of the crystall
ine phase in the gels prepared from ultra-high molecular weight polyethylen
e. The straight chain segment length distribution covers the range from 1 t
o 10 nm with a sharp maximum at 3 nm. The latter peak is attributed to chai
n-folded crystals while the wings of the distribution are referred to the c
ontribution of adjoined straightened portions of different molecules. The c
rystalline sites of both kinds serve as junctions in newly formed polymeric
network. (C) 2001 Elsevier Science Ltd. All rights reserved.