A combined method of chromatography and infrared spectroscopy is employed to map the distribution of monomers in copolymer samples. The method relies on the measurement of spectral peak ratios of the sample, using polymer samples of known composition as calibration standards. The inherent variation of the method was established by measuring a homopolymer of invariant composition. The samples examined were styrene/butadiene copolymers, synthesized by two different polymerization protocols. The technique provided sensitive measurement of comonomer composition across the molecular weight distribution of the samples and is generally applicable to copolymers that can be fractionated by chromatographic methods.
Michael X. Liu and James L. Dwyer, "Quantitative Analysis of Copolymers by GPC/FT-IR," Appl. Spectrosc. 50, 349-356 (1996)