Distribution analysis of functional groups in silicone by on-line size exclusion chromatography/NMR

On-line size exclusion chromatography/nuclear magnetic resonance (SEC/NMR) has been applied to the characterization of polymers. In this study, on-line SEC/NMR was applied to an analysis of silicone, and a suitable condition for determining the molecular weight dependence of the functional groups in silicone was investigated. Deuterated chloroform was used as an eluent, the flow rate was 0.04 ml/min. The amount of sample was 10 mg. A presaturation method was used to reduce the highest signal due to SiCH3. The 1H-NMR spectra were collected every 225 s. Each spectrum was obtained by the accumulation of 420 scans. By on-line SEC/NMR using the above-mentioned condition, a distribution analysis of 10-5 eq./g order of functional groups in silicone has become feasible. It was also found that the times required for a sample treatment and an analysis were 1/30 and 1/3 of the off-line time, respectively. Applications to the analysis of adhesives have proved that this method is useful for the analysis of silicone.