On the Q-factors for poly-1-olefins in gel permeation chromatography

Abstract

The Q-factors for ten poly-1-olefins from poly-1-butene to poly-1-octadecene were determined in 1,2,4-trichlorobenzene at 80°C and 135°C using the universal calibration curve and the elution count-extended chain length calibration curve constructed by use of polystyrene standards. These experimentally determined Q-factors were lower than the theoretical ones, except for poly-1-butene, at both temperatures, in contrast to those for polyethylene, polypropylene, and poly-1-butene. Corrected Q-factors for poly-1-olefins were obtained by correlating apparent Q-factors with the number of carbon atoms in the monomer for a series of poly-1-olefins. By assuming that poly-1-olefins in solution exist as quasi-rod-shaped polymers rather than random coils, it would be presumed that the apparent extended chain lengths of poly-1-olefins experimentally determined are longer than the theoretical ones because of the effects of their long pendent groups which influence the elution positions of poly-1-olefins. A molecule of the poly-1-olefins having the same theoretical extended chain length of a polystyrene molecule elutes earlier than the polystyrene molecule, meaning the extended chain length of the poly-1-olefin molecule is supposed to be longer than that of the polystyrene molecule.