MATL06017 2019 Plastics Materials Processing and Testing

The student is expected to be able to know the definition of polymers and to classify and describe polymers according to respective groups.

Determine and calculate the average molecular weight of the polymer and to describe the implications that arise from molecular weight differences with respect to properties and processing in general.

Describe and identify the various polymerisation system for conducting polymerisation reactions and to compare and contrast the advantages and the disadvantages of the various systems.

Determine the solubility parameter based on the molecular structure of the polymer and to identify and distinguish the factors affecting the polymer solubility

Describe the properties of the crystalline polymers and to explain the formation of crystals in polymers and the factors affecting it.

Identify the processing techniques used to plastics processing (e.g. injection moulding) including the various testing methods employed to test plastic materials.

Introduction to Polymers: This section will cover material in the area of the polymer industry, definition and structures of polymers, basic properties of polymers and classification of polymers.

Polymerization: This section will introduce the learner how to calculate molecular weight average and distribution, the significance of molecular weight control and techniques for molecular weight determination. The module wills also review step-wise, additional and co polymerisation and a review of polymerisation systems.

Polymer Solid and Solution: This section will review polymer solubility, phase separation, crystalline polymers, their structure and melting points. This section will also review amorphous polymers and the different property application relationships.

Polymer processing: Present an overview of the different kinds of processing techniques that are used in the processing of polymers as well as advantages and disadvantages of each type. Introduction to basic principles of mixing, choice and comparison of mixing and compounding systems for specific materials and applications

Extrusion: Basic screw types for single screw extruders, vented extruders. Overview of the main extrusion processes of; tube, wire coating, sheet and film. Design of mixing heads for single screw extrusion. Co-extrusion process. Comparison with twin screw extrusion. Introduction to screw and die characteristics. Fault diagnosis of common processing problems. Basic screw and die design considerations.

Injection Moulding: Construction of machines and types available, hydraulic, electric and hybrid systems. Multi shot systems and micro machines. Types of mould locking systems and tie bar less machines. Screw designs. Moulding cycle Overview of injection moulding non standard materials such as elastomers and thermosets. The effects of moulding conditions and process variables on products, e.g. shrinkage and orientation. Systematic approach to correction of moulding faults. The Economics of Injection Moulding: The moulding cycle and the derivation of typical costing for moulded components. Heating and cooling requirements Machine Safety: Requirements and types of safety mechanisms.

Blow Moulding: Principles of injection and extrusion blow moulding. Parison formation Blowing systems The effect of material properties on the product, also the effect of processing on the product.

Polymer Testing: Introduce the learner to the different methods of testing the defects and quality of polymers and become familiar with the common flaws that occur during polymer processing.

Indicative Practical:

Stress-strain behaviour in tension and flexure.

Fracture toughness properties-Charpy and Izod modes of deformation.

Determination of Tg and Tm and enthalpy of fusion using DSC.

Creep and stress relaxation studies of amorphous polymers.

Temperature and frequency dependence of dynamic mechanical properties.