Polymer Processing

Frontmatter

Introduction

Abstract

This book is intended for engineers and technicians involved in various sectors of the plastics industry (processing, manufacture, and formulation of polymers; more specifically, the design of plastic objects and equipment), as well as students and researchers in physics and chemistry of polymers, continuum mechanics, rheology, modeling, and numerical simulation.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

1. Continuum Mechanics: Review of Principles

Abstract

Phenomenological definitions of strain are first presented in the following examples.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

2. Rheological Behavior of Molten Polymers

Abstract

Newtonian behavior is the simplest approximation of the rheological behavior of polymer melts.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

3. Energy and Heat Transfer in Polymer Processes

Abstract

Consider a system at time t occupying the domain Ω with boundary Γ. The first law of thermodynamics postulates the existence of a thermodynamic state function of the system, called internal energy E

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

4. Approximations and Calculation Methods

Abstract

Polymer processing is generally carried out in complex equipment geometries, especially extrusion dies and injection molds. In most cases, the situation may be examined first as three-dimensional flows, as depicted in Figure 4.1. At any point in the flow, one needs to know the velocity field, u(u, v, w), the six components of the stress tensor, σ, and the temperature T.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

5. Single-Screw Extrusion and Die Flows

Abstract

Extrusion is by far the most important method for shaping polymers. Extrusion is a continuous p ocess based on a screw/barrel system and used to produce finished or semifinished products (films, plates, pipes, profiles, cable insulation) by forcing the polymer melt through a die, as Figure 5.1 illustrates for a line for pipe manufacturing. Extrusion is also used for pelletizing, polymerization, or compounding.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

6. Twin-Screw Extrusion and Applications

Abstract

As discussed in Chapter 5, the second-largest extrusion process is twin-screw extrusion, mainly used for the preparation and processing of complex polymeric materials, through compounding and reactive extrusion. In this chapter, after introducing the different twin-screw extrusion processes, we will focus on the corotating twin-screw extruder for which the main aspects will be detailed, and we will review a number of applications ranging from polymer blends or filled polymers to reactive extrusion.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

7. Injection Molding

Abstracts

Injection molding is used for the mass production of objects with complex shapes. The injection-molding machine consists of a plasticizing/injection unit and a clamping unit in which the mold is fixed, as illustrated in Figure 7.1.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

8. Calendering

Abstract

Calendering covers two distinct types of processes: Film calendering, for the production of thick sheets (from 300 μm to a few millimeters), typically for PVC or elastomeric compounds. Most calendering machines contain more than two rolls (up to five in some cases) with a controlled temperature close to the temperature of the polymer.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

9. Polymer Stretching Processes

Abstract

This chapter is devoted to the different polymer processes in which the flow is predominantly extensional: Fiber spinning, for which the stretching is uniaxial. Film manufacturing by cast-film extrusion or film blowing. Manufacture of hollow bodies by blow molding or stretch blow molding.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

10. Flow Instabilities

Abstract

Until now we have always considered stable flows that allow one to obtain products free of defects. However, it is well known that flows of molten polymers can lead to different types of instabilities, which generally limit the productivity of forming processes (Petrie and Denn, 1976; Larson, 1992; Koopmans, 2002; Hatzikiriakos and Migler, 2004; Vergnes, 2015). We will review these types of instability in this chapter.

Jean-François Agassant, Pierre Avenas, Michel Vincent, Bruno Vergnes, Pierre J. Carreau

Backmatter