EFFECT OF DIE ANGLE ON FLOW BEHAVIOR FOR HIGH-IMPACT POLYSTYRENE MELT

The influence of die angle on the flow behaviour for high impact polys tyrene (HIPS) melt is investigated by using a set of capillaries with a series of entry angles (2 alpha) in this work. It appears that the m elt flow basically obeys the index law; the depen dence of apparent sh ear viscosity (eta(a)) on temperature roughly accords with the Arrheni us equation and the values of eta(a) changes with 2 alpha to some exte nt. The end effect of the melt is significant under experimental condi tions, and the end pressure losses (Delta P-ends) decrease with increa sing 2 alpha; there is a focal minimal value of Delta P-ends at 2 alph a around 75 degrees. (C) 1997 Elsevier Science Ltd.