Different states in orthorhombic crystalline phase of high-density polyethylene

Two-dimensional (2D) FT-IR spectroscopy along with high-resolution and cryo genic techniques was used to investigate the CH2 rocking bands (750-700 cm( -1)) of high-density polyethylene (HDPE). The 2D asynchronous spectrum show s that multiple forms of orthorhombic polyethylene co-exist in HDPE. Each o f the two orthorhombic bands around 730 and 720 cm(-1), is composed of at l east two sub-bands. The differences in peak position for the sub-bands are less than 1 cm(-1). The co-existence of multiple orthorhombic polyethylene may be helpful in understanding the variation of the peak positions, bandwi dths and relative intensities of the orthorhombic polyethylene bands of pol yethylene. (C) 2001 Elsevier Science B.V. All rights reserved.