The objective of this work is to determine reactivity ratios of the poly(α-methylstyrene-co-butadiene) polymerization in cesium-based catalyst system. These values can be used to describe the characteristic incorporation order of the monomers into the polymer chain and model the chain microstructure. The anionic solution polymerization of α-methylstyrene and 1,3-butadiene was polymerized at 10°C with different feed ratios in the presence of Cesium alkoxide, dialkyl magnesium, and chelating diamine. The reactivity ratio for butadiene at 50/50 wt% (35/65 molar ratio) α-methylstyrene/butadiene calculated as approximately 1.50, while that for α-methylstyrene calculated by both the integrated and differential methods were the values of 0.40 and -0.1. This would indicate that copolymer composition equation need to be modified to include propagation-depropagation equilibrium phenomenon.
Kwang Su Seo, Susan A. Lettieri, Steve K. Henning, Weng-Liang Hsu and Adel F. Halasa