Synthesis of Polystyrene and Molecular Weight Determination by 1H NMR End-Group Analysis

A procedure for the solution polymerization of styrene using di-tert-butyl peroxide (DTBP) as the initiator is Monomer described. The use of DTBP allows for end-group analysis by H-1 NMR spectroscopy and calculation of the number-average molecular weight of the polymer. This experiment was designed as a laboratory introduction to polymer chemistry for second-year undergraduate students. The highest-order focus was to get students to derive an equation to calculate the number-average molecular weight by H-1 NMR spectral analysis.