Molecular Weight Calibration of SEC Using Broad MWD Standards-Application for Poly (P-Methyl Styrene)

Abstract

Broad molecular weight distribution samples of poly (p-methyl styrene) were synthesized using free radical polymerization with thermal initiation over a range of temperatures, 120°–160°C. The weight-average molecular weights (Mw) of these polymers were measured by low angle laser light scattering photometry (LALLSP) to provide broad MWD standards. Two broad MWD standards were then used to determine the molecular weight calibration curve for poly (p-methyl styrene) using the universal molecular weight calibration curve found using narrow MWD polystyrene standards. SEC was then used to measure the Mw values for the remaining poly (p-methyl styrene) samples. The M_v values by LALLSP and SEC were in excellent agreement confirming the validity of the broad MWD standards calibration method.