... E.G, Extrusion of Plastics, Newnes-Butterworth, 1976. Schenkel, G, Plastics Extrusion Technology and Practice, Iliffe, 1966. Fisher, E.G, Blow Moulding of Plastics, Iliffe, 1971. ... ( dr' dr - dr )) 350 Analysis of polymer melt flow V= 211 dz Now at y = 0, V = VO so 1dP H 211 dz vo = (z) Substituting aP/az in the expression for V gives ... graphically as shown in Fig. 5 .11. 2.6 2.4 2.2 0 c E2 UJ C I 1.8 a, 3 v, 1.6 1.4 1.2 1 0 1 2 3 4 5 6 7 8 Recoverable shear strain Fig. 5 .11 Variation of Swelling...