Fractionation of polymers of higher α‐olefins

Fractionation of 1–10 g. samples of a series of poly‐α‐olefins in a glass bead column has been studied. A thermal gradient was found to decrease fractionation efficiency relative to that obtained at constant (ambient) temperatures. A “stepwise‐continuous” solvent gradient technique was developed to improve fractionation of the high molecular weight material. Fractionation efficiency decreased with increasing bead loading but was still good at polymer to bead ratios of 0.1 compared to the ratio of 0.01 usually used; efficiency is poorer in the absence of a column, even when the latter is operated at constant temperature. The Kuhn‐Mark‐Houwink equation was used to correlate intrinsic viscosities to light‐scattering molecular weights. Values of the constants were K = 2.1 × 10−4 and α = 0.61. Molecular weight distribution correlations show these polymers to have very high Mw/Mn.