RAMAN-SPECTROSCOPY EMPLOYED FOR THE DETERMINATION OF THE INTERMEDIATE PHASE IN POLYETHYLENE

The original work of Strobl and Hagedorn suggesting the presence of a third intermediate phase in semicrystalline polyethylene was revisited. The current study, involving the collection of Raman spectroscopic data on a set of 16 polyethylene samples recorded on two different types of instruments in two different laboratories and employing two different methods of curve fitting to both sets of experimental data, has revealed that the claims in the original paper cannot be asserted. The most important reason leading to this conclusion is a problem incorrectly describing the complicated overlapping spectral structure in the 1000-1200 and 1400-1500 cm(-1) spectral ranges. It is noted that the contribution of the melt in the 1000-1150 cm(-1) range cannot be described by a single line centered around 1080 cm(-1). The present results indicate that the quantification of a third, intermediate, phase in polyethylene is not possible when based on standard Raman spectra.