DETERMINATION OF ALKYLATED POLYSTYRENE POUR POINT DEPRESSANT BY PREPARATIVE GEL-PERMEATION CHROMATOGRAPHY, INFRARED SPECTROMETRY AND NUCLEAR-MAGNETIC-RESONANCE SPECTROMETRY

This paper deals with the determination of alkylated polystyrene pour point depressant by infrared spectrometry, and nuclear magnetic resona nce spectrometry after separation of the polymers and low molecular ad ditives by preparative gel permeation chromatography. First the molecu lar weight distributions (MWDs) of the products are determined by anal ytical gel permeation chromatography. Then the polymer and low molecul ar weight components are separated by preparative gel permeation chrom atography because the polymer cannot be separated from base oil and ot her additives by fractional precipitation. The polymer and other addit ives are determined by Fourier transform infrared spectrometry (FTIR) and nuclear magnetic resonance (NMR) spectrometry. The relation betwee n concentration and molecular weight is also studied. (C) 1998 Elsevie r Science B.V. All rights reserved.