EFFECT OF GRAFTING ON RUBBER-PHASE OXIDATIVE ETCH RESISTANCE IN HIGH-IMPACT POLYSTYRENE

A relatively simple, reproducible method for the determination of grafting in high‐impact polystyrene (HIPS) shows that high‐ and low‐graft HIPS exhibit differences in morphology following treatment with an oxidative etching solution. Because this method is quite sensitive to small differences, it yields a more definitive evaluation of grafting in the finished polymer than any other previously used analytical procedure. These differences have been quantified, and the data used to compare relative grafting in polystyrenes reinforced with the same or different rubber types. The method shows an increase in grafting when either the peroxide initiator feed level or 1,2‐vinyl content of the polybutadiene is increased. Copyright © 1979 John Wiley & Sons, Inc.