Branching analysis of star-shaped polybutadienes by temperature gradient interaction chromatography-triple detection

Size exclusion chromatography (SEC) coupled with triple detection (TD) method is widely used for branching analysis of polymers. However, there is an inherent limitation of SEC-TD method that SEC separates polymers according their hydrodynamic size. The SEC resolution of branched polymers is not high since the hydrodynamic size of branched polymers does not change as much as linear polymers with molecular weight (MW), let alone the serious band-broadening in SEC. As a solution of the problem, we propose temperature gradient interaction chromatography (TGIC)-TD method taking advantage of TGIC's characteristics of separating branched polymers according to their MW with much higher resolution than SEC. The potential of the method was demonstrated using regular star-shaped polybutadienes prepared by anionic polymerization. They were characterized by both SEC-TD and TGIC-TD methods. Detailed analysis of branch distribution was possible for narrow MW fractions in TGIC-TD while SEC-TD only provides with average branch number for SEC fractions.