Production of Highly Monodisperse Polystyrene by Evaporative Purification
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In this thesis, I will demonstrate a simple evaporative purification method to separate a polydisperse polystyrene with small molecular weight into highly monodisperse components (N-mers) ranging from 3-mers to 13-mers. This method has been applied to polystyrene samples of Mw= 600 g/mol and Mw= 890 g/mol with narrow molecular weight distribution, as well as a polystyrene sample of Mw=1200 g/mol with broader molecular weight distribution. In each case, the samples were successfully separated into milligram (mg) quantities of N-mers with N ranging from 3 to 13. The vapor pressure of each N-mer is calculated by using a simple lattice model and calculations suggest the isolated components have Mw/Mn values less than 1.001 and, through a second iteration of the process, Mw/Mn could become as low as 1.000003. The glass transition temperature (Tg) of each separated component is characterized by the differential scanning calorimeter and the Tg values of these components are independent of the sample they originate from. Based on the Tg values of these pure components, the Fox equation for the Tg of mixtures is developed into a simple relation which is able to accurately quantify the Tg values from oligomer to polymer.
Cite this work
Shipei Zhu (2017). Production of Highly Monodisperse Polystyrene by Evaporative Purification. UWSpace. http://hdl.handle.net/10012/12723