Determination of alkylated polystyrene pour point depressant by preparative gel permeation chromatography, infrared spectrometry and nuclear magnetic resonance spectrometry Original Research Article

This paper deals with the determination of alkylated polystyrene pour point depressant by infrared spectrometry, and nuclear magnetic resonance spectrometry after separation of the polymers and low molecular additives by preparative gel permeation chromatography. First the molecular weight distributions (MWDs) of the products are determined by analytical gel permeation chromatography. Then the polymer and low molecular weight components are separated by preparative gel permeation chromatography because the polymer cannot be separated from base oil and other additives by fractional precipitation. The polymer and other additives are determined by Fourier transform infrared spectrometry (FTIR) and nuclear magnetic resonance (NMR) spectrometry. The relation between concentration and molecular weight is also studied.