CHED 717 |
| An undergraduate research experiment was designed monitoring the nitroxide mediated polymerization of styrene. The reaction was carried out with 2,2' – Azobisisobutyronitrile (AIBN) as the initiator, anisole as the internal standard, and 2,2,6,6-Tetramethyl-piperidin-1-oxyl (TEMPO) as the mediator. Reagents were used as received with only minimum purification of styrene using alumina filtration to remove inhibitors. Reactions were carried out at 130 oC in nitrogen-flushed round bottom flasks equipped with rubber septa to allow for removal of aliquots during the reaction. These aliquots were taken at varying time intervals and immediately quenched by placing them in an ice bath. Monomer conversion was obtained using gas chromatography (GC) by comparing the relative peak areas of styrene to the internal standard, anisole. Molecular weights and polydispersity indices (PDI) were obtained on the same samples using gel permeation chromatography (GPC) calibrated with polystyrene standards. Number average molecular weight (Mn) values showed a linear dependence on percent monomer conversion, indicating that the reaction proceeded in a controlled manner consistent with nitroxide mediated polymerization. This experiment is designed to give students experience in modern synthetic polymer chemistry and characterization. |
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Undergraduate Research Poster Session: Polymer Chemistry
11:00 AM-1:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster
Division of Chemical Education |