Nondestructive Quantitative Analysis of Ethylene-Propylene Blend Polymer by the NIR/ATR/FT-IR Method

Abstract

The attenuated total reflectance Fourier transform infrared (ATR/FT-IR) method in the near-infrared region was found to provide a novel opportunity for nondestructive analysis of ethylene-propylene (EP) blend polymer. The absorption due to the overtone of the C-H stretching vibration at ∼5900 cm −1 was utilized to determine the ratio of two monomer units, the ethylene and propylene units, of the blend polymer, since the overlapping of CH 3 - and -CH 2 - is not so prohibitive as in the case of the fundamental C-H stretching vibration at ∼2900 cm −1 . The well-known disadvantage of the weak intensity of the overtone absorption, however, was overcome by the choice of the high-sensitivity FT-IR technique.