ABSTRACT

Extrusion is known as a complex and dynamic plasticating process in converting thermoplastic raw materials into more useful products. It is capable of generating high temperature and high pressure without sacricing pumping capacity. Foaming virtually became an interesting application of

CONTENTS

12.1 Introduction ................................................................................................ 377 12.2 Thermoplastic Foam Extrusion Processes ............................................. 379

12.2.1 High-Density Foam Process ......................................................... 379 12.2.2 Low-Density Foam Process ..........................................................380

12.3 Mixing-Theories and Experiments ....................................................... 381 12.3.1 Distributive Mixing ....................................................................... 382 12.3.2 Dispersive Mixing ......................................................................... 391

12.4 Mixing Practices in Single-and Twin-Screw Extruders ...................... 396 12.4.1 Mixing Sections in Single-Screw Extruders .............................. 397 12.4.2 Mixing Sections in Co-Rotating Intermeshing Twin-Screw