Correlation between comprehensive 2D liquid chromatography and Monte Carlo simulations for branched polymers

Detailed knowledge on structural information is required to derive the rheological properties of branched polymers. Size-exclusion chromatography with triple-detection (TD-SEC), comprising a concentration, a light scattering, and a viscosity detector, is a powerful tool to analyze the degree of branching of polymers as a function of their molar masses. However, TD-SEC alone is incapable of fully deconvoluting complex polymer systems. In this study we discuss a more sophisticated approach that includes coupling of TD to our recently described novel online two-dimensional liquid chromatography method (2D-LC), based on solvent gradient at near-critical conditions in the first dimension. Thus, a contour plot of the branching ratio is presented, and unique detailed information on the degree of branching can be derived for branched polycarbonate (PC) sample. Furthermore, the molar mass distributions of separated linear and branched PC chains as well as their fractions in the polymer are quantified. The corresponding data are correlated to Monte Carlo simulations of the polycondensation process of a branched PC, and both methods show a high level of agreement in the determined molar mass distributions of the linear and branched PC chains as well as their fractions. Finally, the influence of chemical structure on rheological properties is demonstrated.