Rabinowitsch correction factor, 372 Ram extruder, 371 Reaction injection moulding, 302 Reactive extrusion, 278 Real modulus, 112 Reciprocating screw injection, 281 Recoverable shear strain, 345 Recovery, 24, 43, 87, 89, 94 Reduced time, 104 Refractive index, 34 Reinforcement, 3 Relaxation, 42, 87, 89, 93 Relaxation modulus, 49 Relaxation time, 87, 367 Relaxed modulus, 51 Residence time, 367 Residual strain, 109 Resin injection, 335 Resistance, 32 Retardation time, 88 Rheological models, 351 Rib design, 74 RIM, 302 [Pg.504]

Polymer melts are frequendy non-Newtonian. In this case the earlier expression given for the shear rate at the capillary wall does not hold. A correction factor (3n + 1)/4n, called the Rabinowitsch correction, must be appHed in such a way that equation 21 appHes, where 7 is the tme shear rate at the wall and nis 2l power law factor (eq. 22) determined from the slope of a log—log plot of the tme shear stress at the wad, T, vs 7. For a Newtonian hquid, n = 1. A tme apparent viscosity, Tj, can be calculated from equation 23. [Pg.183]

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