Polymers Contaminated by Small Amounts of Admixtures: Errors in the Average Molar Masses when Measured by SEC with a Concentration Detector

VEGA, J.R.; BEREK, D.; MEIRA, G.R.

Bahía Blanca

Simposio; IX Simposio Argentino de Polímeros - SAP 2011; 2011

Based on simulated examples, this work evaluates the errors in Mn, Mw, and Mn/Mw, as determined by size exclusion chromatography with differential refractometer (SEC/DR), when a main polymer (A) is contaminated by small amounts of a secondary polymer (B). The simulations assume different column resolutions and amounts of admixture B. The presence of a minor admixture can dramatically alter the average molar masses of a main polymer as determined by SEC/DR. For the sake of simplicity, the simulated examples have not considered the effect of column selectivity that is reflected in the slope of calibration dependence. Also not considered was the use of UV-vis detectors for determining the instantaneous concentration of one of the homopolymers.