Mark-Houwink Parameters for the Universal Calibration of Acrylate, Methacrylate and Vinyl Acetate Polymers Determined by Online Size-Exclusion Chromatography-Mass Spectrometry

Size exclusion chromatography coupled online to electrospray ionization mass spectrometry (SEC/ESI-MS) is employed to establish universal calibration (UC) relationships for a number of linear poly(alkyl acrylates) and poly(alkyl methacrylates) (pmmAs) as well as poly(vinyl acetate) synthesized via radical chain transfer polymerization. It is demonstrated that in the analyzed molecular weight range, Mark-Houwink-Kuhn-Sakurada (MHKS) coefficients can be successfully determined in relation to values of pMMA. The agreement between the UC model using mass spectrometry-derived MHKS coefficients and the measured data was generally better than 10%. The MHKS values reported herein are expected to remain valid up to 20 kDa. A comparison with the outcome of UC using literature reported MHKS coefficients determined by intrinsic viscosity - molecular weight (IV-MW) measurements is provided. Errors of more than 30% can result when these literature values are employed in the low molecular weight range ((M) over bar (n) < 20 kDa). Use of MHKS coefficients derived from IV-MW measurements in UC is, therefore, strongly discouraged at molecular weights below 20 kDa.