Assessment of errors in the determination of mark-houwink-sakurada and stockmayer-fixman constants using size-exclusion chromatography with on-line viscometric detection: Analyses of poly(p-substituted styrenes) in tetrahydrofuran

In this work, we present values for the Mark-Houwink-Sakurada (MHS) and Stockmayer-Fixman (SF) constants for a series of homopolymers of para-substituted styrenes (4-X-styrene; X = OCH₃, OCH₂CH₃, CH₃) F, Cl, and Br) in THF at room temperature. The respective values of K (in 10^-5 dL/g) and a were: 0.685 and 13.2; 0.662 and 14.1; 0.740 and 8.41; 0.781 and 5.24; 0.726 and 8.95; 0.700 and 7.79. The respective values for K_θ (in 10^-4 dL/g) and K' (in 10^-7 dL/g) were: 6.01 and 16.1; 6.22 and 9.07; 7.64 and 17.4; 5.59 and 23.7; 6.29 and 17.3; 4.44 and 10.3. These constants were measured using size-exclusion chromatography with on-line viscometry. As part of this work, we investigate the applicability of common model fitting procedures to this method of measuring MHS/SF constants and the effect of uncertainties in their estimated values on the accuracy of molecular weight analysis.