Measurement of the Viscoelastic Coefficients of Main-Chain Nematic Polymers by an NMR Technique

We propose a simple NMR technique, and the underlying theory, to evaluate, with high accuracy, four out of the five viscosity coefficients and the ratio k₃₃k₁₁ of the bend to splay Frank elastic constants, in nematic polymers. Quantitative data on the viscosities γ₁, α₁, α₂, and ηc and the ratio k₃₃k₁₁ are given for the first time for a thermotropic nematic polymer. The material studied is poly (4,4{'}-dioxy-2,2{'}-dimethyl azoxybenzenedodecanediyl), a linear polyester usually labeled DDA9.