Rapid Method for Estimation of Ethylene Content in Ethylene-Propylene Copolymers

By : Ravindra Kumar , Veena Bansal , Sujit Mondal , G.S. Kapur , V. Kagdiyal , Deepak Saxena

Page No: 75-85

Abstract
Accurate characterization of ethylene-propylene copolymer (EPC) composition and triad sequence distribution is critical for understanding structure–property relationships, developing product specifications and for researchers involved in new product development. Generally, the 1 H NMR spectra of olefins copolymers are difficult to analyze in terms of composition and sequence distribution information due to severe overlapping of resonances in a short chemical shift region of 0.5-2.0 ppm. In this work Heteronuclear Single Quantum Coherence (HSQC) has been used to revise the interpretation of the 1 H NMR spectra of EPC. Based on this interpretation ethylene content has been estimated by 1 H NMR spectroscopy and found to be in close agreement with that of the 13C NMR (R2 =0.9929). The role of stable tune-match and shimming in acquiring a high quality 13C NMR spectrum at high temperature has also been discussed along with a revised 13C NMR methodology.

Authors :
Ravindra Kumar, Veena Bansal, Sujit Mondal, G.S. Kapur, V. Kagdiyal and Deepak Saxena : Indian Oil Corporation Limited, Research & Development Centre, Sector-13, Faridabad-121007