ABSTRACT
This chapter introduces the principles of fluid flow and heat transfer, together with properties which are relevant to the melt processing of thermoplastic polymers. Conduction occurs in polymers in moulds, for example in the cooling of injected thermoplastics or in the heating of compressed or injected crosslinkable polymers. Convection is important within melt flows, in cooling of thermoplastics extrudates in air or in a water bath, and in heating of rubber extrudates as they pass through a vulcanization chamber. Radiation can account for a substantial amount of heat loss as thin films cool during the manufacture of tubular blown film. The chapter revises the analysis of particular one-directional isothermal Newtonian flows caused by pressure or drag, reviews the viscous shear behaviour of melts, and reworks the analyses for power-law fluids.
