Polymer processing

After a brief introduction to the various types of polymers in use and the size and impact of the polymer processing industry, this overview focuses on the most important processes for thermoplastic materials, namely extrusion and injection moulding. Single and twin screw extruders are used for melting and pumping of polymers and for die extrusion for the production of film, sheet, pipe, tubing, profiles and fibres. Injection moulding is the process used for the production of numerous parts, small and large, by injecting a molten polymer into mould cavities. Various problems associated with these processes are discussed. Other processes described include: calendering, compression moulding, rotational moulding, powder injection moulding and thixomoulding. The overview concludes with a brief discussion of current trends and future challenges faced by the polymer industry.