Electrochemically controlled molecular weight of polystyrene production

Summary

It is well known that physical properties such as mechanical and thermal characteristics of a polymer are highly dependent on its molecular weight and molecular weight distribution (MWD). This feature encourages our interest for finding suitable conditions that allow us to control the molecular weight of the formed polymer, by controlling the experimental parameters. We are reporting some results about the electropolymerization of styrene in tetrahydrofuran with tetrabutylammonium tetrafluoroborate and sodium tetraphenylboron as supporting electrolytes. From the electrolyses using tetrabutylammonium tetrafluoroborate two molecular weight distribution curves, showing weight average molecular weight values ($\overline {{\text{MW}}}$) of 3.6×10⁵–1.7×10⁶ for the first and 5×10³ for the second one were observed. When using sodium tetraphenylboron a unique distribution curve was displayed suggesting that the weight average molecular weight of the polystyrene, increases by increasing the current density; the observed MWD being rather low.