Sedimentation analysis of 1,4‐cis‐polybutadiene in a theta solvent, diethyl ketone at 10.3°C

摘要

AbstractA sedimentation and viscosity study of 1,4‐cis‐polybutadiene (having 95 1,4‐cisunits) in a θ‐solvent diethyl ketone (DEK) at 10.3°C. is reported. The limiting sedimentation coefficientsoand the limiting viscosity number ηθ of themonodispersesample of this polymer in the given θ‐solvent as functions of its molecular weightMare derived from data on polydisperse fractions by application of the method described by Homma et al. The results are:so= 0.530 × 10−15M1/2(in sec.) and ηθ = 1.60 × 10−3M1/2(in dl./g.). Substitution of the experimental data into the well‐known Mandelkern‐Flory equation yields 1.74 × 106for the familiar parameter Φ1/3P−1, which is about 30 lower than the usua