CHARACTERIZATION AND ANALYSIS OF POLYMERIC ADDITIVES IN OILS BY PYROLYSIS-GC

Blends of certain polymers and copolymers (''V.I. improvers'') may be dissolved in lubricants in order to reduce the tendency of the oil to become less viscous with increase in temperature. Analysis of such polymer mixtures may not be easy by conventional methods; spectroscopic results, for example, provide general indications of the polymer types, but cannot easily be used to specify the components precisely, or to analyse them quantitatively. The work described in this paper shows that, in many cases, the complete characterization and quantitative analysis may be performed readily under controlled conditions by pyrolysis-g.c. of the precipitated additive. The method is ideal for the assessment of multicomponent alkyl methacrylate polymers, which are amongst the most frequently used V.I. improvers. No ancillary techniques are necessary if appropriate monomers are available as reference compounds. In the absence of such compounds, pyrolysis-g.c.-mass-spectroscopy facilities are useful for the characterization work.