Polymer Processing and Recycling


The main objective of this course is to provide students with knowledge about different methods of processing and recycling of polymers, their equipment and procedures. At the end of the course the student should be able to choose the most appropriate method for the manufacture of a given object, and choose the most appropriate procedure in each case. It should also be able to choose the most appropriate method for valuation of a given polymeric solid waste and implement it.


General characterization





Responsible teacher

Maria Teresa Varanda Cidade


Weekly - 5

Total - 75

Teaching language



It is recommended that the students have obtained positive classification in Chemistry of Polymers, Physics of Polymers and Rheology of Materials.


“Plastics Engineering”, R.J. Crawford, Pergamon Press, 1987.

Matiéres Plástiques II”, Jean Bost, Technique & Documentation, 1986.

“Tecnologia de Transformação de Plásticos – Texto de Apoio”, M. T. Cidade, FCT/UNL, 1995.


“Recycling and Recovery of Plastics” J. Brandrup (Ed.), Hanser Publishers, 1995.

“Polymer, The Environment and Sustainable Development”, A. Azapagia, A. Emsley, I. Hamerton, John Wiley & Sons, 2003.

Teaching method

Part I - Processing

With regard to the theoretical contents, exposure of matter will be taken resourting to data show. The slides will be made available to students on the course page. This page will contain all elements relating to the discipline: objectives, program content, scheduling of different types of classes, methods of assessment, problems, scripts of practical work, methods and assessment results, recommended bibliography and summaries.

Concerning problems, students will be asked to solve them previously, the classes serving for correction and clarification of doubts. At the end of the classes of problems, all students, whether they have done, or not, prior resolution of the proposed exercises, will be aware of the resolution, which will be made in the chalkboard, whenever possible by the students themselves.

For practical content, a  laboratory class will be given concerning where an extruded plastic tape will be prepared and there will be a field trip in which students will take contact with different technologies, such as injection molding, thermoforming and calendering

Part II-Recycling

The theoretical concepts will be taught in a manner analogous to Part I.

A study visit will also be performed, to a polymer recycling facility.  Some case studies will be undertaken.

Evaluation method

The final grade is obtained resorting to the formula

NF = 70% NT + 30% NP 


NT - classification of the tests or exam

NP - calssification obatined in the questionnaires concerning the laboratory classes and field trips

Np - classification given by the participation of the student in the problem resolution lessons, that will take into account not only the individual, previous, resolution of the problems, but also the number of assisted lessons and the participation during the lessons itself.

Note: TE students can''''''''t be penalized for not assisting the classes of exercices (as long as they present justification by the employer for each of the days missed). In such case they will receive 10 in Np unless they assist some classes in which case the results of such classes will be taken into account.

NT will be found resorting to 2 tests or the exam. The first and second tests will enter in the calculation with 60% and 40%, respectively. The same percentage will be applied in the exam, concerning the first and second module (processing and recycling).

The students who obtain, as a classification of continuous assessment, a minimum of 9.5 val will be exempt from examination. Those who having frequency do not obtain the minimum for exemption from examination (minimum of 8 val in tests and in questionnaires), have access to the exam. The frequency is obtained by the weighted average of the two questionnaires (60/40), with a minimum of 9.5.


The TE students are obliged to attend the lab classes and field trips

20% of NT can be obtained through the oral presentation of a chapter of the program carried out by the student 

The frequency will be assigned for a period of two years.

Subject matter

Introduction: batch and continuous processes, techniques and examples of final articles manufactured by these two types of processes.

Extrusion (plates, sheets and films, fibers and monofilaments, extrusion-blowing, extrusion-coating of electric wires and granulation-extrusion), injection molding, injection blow molding, calendering and thermoforming: process steps, equipment and procedures: materials and applications. Processing including composite laminates.

Particular case of thermoset processing: compression molding, transfer and injection molding: equipment, procedure. Brief reference to other technologies: reaction injection molding (RIM), rotational molding, cast thermoplastics, coatings, co-injection, pultrusion, SMC, manufacturing of foams..

Polymeric waste recovery. Life cycle of a polymeric material; recovery, material, organic and thermal of solid waste.

Mechanical recycling, reduction, classification / separation, decontamination washing, drying, automated methods of intensive decontamination, selection / separation, processing / additivation.


Programs where the course is taught: