Module information on this degree can be found below, separated by year of study.

The module information below applies for the current academic year. The academic year runs from August to July; the 'current year' switches over at the end of July.

Students select optional courses subject to rules specified in the Mechanical Engineering Student Handbook,  for example at most three Design and Business courses. Please note that numbers are limited on some optional courses and selection criteria will apply.

Structure, Properties and Applications of Polymers

Module aims

  • To develop an understanding of the mechanical properties, processing characteristics and failure modes of the principal classes of polymers, in terms of their structure
  • To define and familiarise some of the basic vocabulary and concepts needed to understand the technical literature of polymers and to communicate with specialists in the field
  • To develop familiarity with the processing technologies available for plastics, and the ways in which they influence the design and properties of plastic components
  • To develop a critical appreciation of the methods used to measure mechanical property data for plastics, to present such data to designers, and to use such data for material selection.

ECTS units:  6   
Contributing to Course Elements: 6 to ME3-LCTVS or ME4-LCTVS

Learning outcomes

On successfully completing this module, students will be able to:

  • Discuss, using appropriate technical vocabulary, the inter-relationship between structure, processing and mechanical and physical properties of polymeric engineering materials
  • Recall the principal standard test methods used to measure polymer property data
  • Recall typical mechanical and physical properties of representative polymers in each main class
  • Explain the principle phenomena of temperature-dependent viscoelastic behaviour on on physical grounds, in terms of simple spring-dashpot models.
  • Select a generic polymer for given service conditions, accounting for limitations of processability and recyclability
  • Propose a suitable method for processing a specified polymer to a given shape
  • Solve instructive problems involving viscoelastic behaviour using the pseudoelastic method, spring dashpot models or the Boltzmann superposition principle, as appropriate.

Module syllabus

  • Structure-property relationships: monomers, oligomers and polymers. Molecular weight. Thermoplastics. Blends and copolymers. Conformation and configuration of C-C backbone chains; tacticity. Chain flexibility and mobility. Amorphous polymers in melt, rubbery and glassy states. Entanglements. Chain mobility under stress. The glass transition: factors affecting its value. Crystallinity. Factors affecting crystallinity and Tm. Orientation. Liquid crystal polymers. Elastomers and thermosets. Thermoplastic elastomers. Alloys and blends. Additives. Introduction to polymer composites and foams.
  • Designing with plastics: Selection of plastics on the basis of previous applications. Selection from a property database: CES Edupak. Campus. Recognising polymers.
  • Aspects of design for injection moulded rigid components: fixing, joining and consolidation features (snap-fits, moulded-in hinges etc.). Post-moulding processes. Design for and methods of recovery, recycling and disposal.
  • Processing of polymers: Principal methods of processing plastics, rubbers and short-fibre composites (extrusion, blow moulding, calendaring, rotational casting, thermoforming, compression moulding, injection moulding and their derivatives). Polymer melt properties. Melt flow index. Melt viscosity: strain rate and temperature effects. Melt elasticity, slip and fracture. Shrinkage. Mouldability: the spiral flow test. Curing of thermosets and rubbers. Processing effects on properties of extruded and injection moulded components. Flow line orientation. Incomplete and shear-promoted crystallisation. Residual stresses. Moulding faults and warping.
  • Stress analysis of polymers: Stress, strain, rate and time. Viscoelasticity in creep and relaxation behaviour: linear elastic, Newtonian viscous and viscoelastic response. Spring-dashpot models: Maxwell, Voigt and standard linear solid. Equations of state. Temperature dependence.
  • Use of creep and relaxation data: Isochronous curves, non-linearity; tangent, secant, flexural and tensile modulus. The pseudoelastic design method. Boltzmann superposition principle applied to stepwise changes in stress or strain. Temperature effects. Stiffness of elastomers.
  • Failure of polymers: The causes of, phenomena of, tests for and design against bulk failure modes (yield, creep rupture, thermal fatigue, solvent attack and swelling, electrical breakdown, combustion); surface failure modes (wear, chemical attack, weathering, stress whitening, crazing, tracking) and 'brittle fracture' modes (slow and environmental stress cracking, fatigue crack growth and impact fracture). Strengthening and toughening of plastics.

Teaching methods

  • Duration: Autumn and Spring terms (21 weeks)
  • Lectures: 1 x 1hr per week

Summary of student timetabled hours

Autumn

Spring

Summer

Lectures

10

11

-

Tutorials

Approx 2-3 hrs per term.

Total

25 (if 4 tutorials attended)

Expected private study time

3-4 hrs per week

Assessments

Written examinations:

Date (approx.)

Max. mark

Pass mark

Structure, Properties and Applications of Polymers (3hrs)

This is a CLOSED BOOK Examination.

April/May

200

n/a

Reading list

Supplementary

Module leaders

Dr Ambrose Taylor