Control of Molar Mass Distribution in Polymers
Andreas Spinnrock and Helmut Cölfen, University of Konstanz, Germany, have combined analytical ultracentrifugation (AUC) with polymer chemistry to obtain desired broad molar mass distributions. The analytical ultracentrifugation was used to adjust a macroinitiator's concentration gradient to control the molar mass distribution after subsequent polymerization. Depending on the rotational speed, the macroinitiator forms the desired concentration gradient. It can be detected at any point by optical systems. After the centrifugation, a free-radical polymerization is initiated by light.