Determination of the composition and structure of polymers by pyrolysis gas chromatography

The applications of pyrolysis gas chromatography for quantitative analysis of copolymers and for the evaluation of their microstructure are described. Three types of widely accepted pyrolyzers were examined to determine their different applications and to select the most satisfactory ones for quantitative analysis. It was established that all types of pyrolyzers may be used for the determination of the composition of copolymers and that a Curie-point pyrolyzer is preferable for the evaluation of polymer microstructure. The pyrolysis gas chromatographic conditions of different copolymers and rubber mixtures are given in this paper. The linear relationship between the ratio of characteristic peak areas and the ratio of the concentration of monomer units in copolymers was used for the determination of copolymer composition using the pyrograms. The difference that was found between the ratio of peak areas for block and random copolymers was used for the evaluation of the sequence distribution of monomer units. The optimum pyrolysis temperature was determined for that purpose. An equation for calculating the contents of monomer units in blocks is suggested.