Monte Carlo simulation of size exclusion chromatography for branched polymers formed through free-radical polymerization with chain transfer to polymer

摘要

The elution curves of size exclusion chromatography (SEC) for branched polymers, formed through free-radical polymerization that involves chain transfer to polymer were theoretically investigated by using a Monte Carlo method. We considered two types of measured molecular weight distribution (MWD), (1) the calibrated MWD relative to standard linear polymers, and (2) the MWD obtained by using a light scattering photometer (LS) in which the weight-average molecular weight of polymers within the elution volume is determined directly. It was found that the calibrated MWD clearly underestimates the high molecular weight tail, and the measured distributions are narrower than the true MWD. On the other hand, the present simulation results showed that the LS method gives reasonable estimates of the true MWDs. The mean square radius of gyration of the polymer molecules having the same molecular weight was also investigated. The radii of gyration showed clear deviation from the Zimm-Stockmayer equation ([1]) because of the non-random nature of branched structure and the difference in the primary chain length distribution. [References: 29]