Denitrogenation of acrylonitrile-butadiene-styrene copolymers using polyethylene glycol/hydroxides

Alkaline hydrolysis of acrylonitrile-butadiene-styrene (ABS) copolymers has been systematically investigated to demonstrate the use of reaction systems based on polyethylene glycol (PEG)/hydroxides for N-elimination from ABS. The structure of denitrogenated ABS has been characterized using elemental analysis, FTIR, 1H-NMR, and solid state 13C CP-MAS NMR, indicating sequential hydrolysis as a plausible mechanism of elimination of N from ABS. The effects of reaction conditions such as solvent selection, reaction temperature, alkaline species and concentration, as well as PEG molecular weight were evaluated. At optimal conditions (THF, PEG600, 4.3 wt % of NaOH), as much as 93.1% of the original nitrogen content of ABS was removed in 2 h at 160 °C, while it is only 35.6% without PEG. This clearly demonstrates the high-efficiency of a PEG/hydroxides catalytic system for denitrogenation of ABS, stressing the potential of this method for denitrogenation of other N-containing polymers.