The aim of this course is to explain the degradation phenomena affecting a polymer during the different phases of its life, from synthesis to processing and disposal, the relative reaction mechanisms in different scenarios, the influence of these phenomena on the physico-chemical properties of that polymer, the main methods of analysis of degradation phenomena and indispensable stabilization processes. Particular attention will be given to the environmental implications of the (bio) degradability of polymers. The aspects relating to combustion and the fire risk in the use of polymers in closed environments, such as means of transport, public and private buildings and workplaces will also be examined in depth.
Expected learning outcomes
Students will know the degradation phenomena affecting a polymer during the different phases of its life and will be able to identify factors that determine the degradation of a polymer and their influence on the resulting physico-chemical properties. They will master main advanced analytical techniques of degradation phenomena, such as high-speed thermogravimetric analysis, flash-pyrolysis and pyrolysis-flow combustion calorimetry and for the study of polymer combustion.
Lesson period: Second semester
(In case of multiple editions, please check the period, as it may vary)
1. THE LIFE-CYCLE OF POLYMERS: from synthesis to disposal. Introduction to polymer life-cycle: synthesis, processing, service life and end-life of polymers. The role of plastics in daily life. A history of polymers and plastics. Polymer properties and classification. Analysis of the European plastic production and demand. 2. THE SERVICE LIFE OF POLYMERS (I): THERMAL DEGRADATION. Introduction to polymer degradation mechanisms. Difference between thermal decomposition and degradation. Definition of chemical and physical agents that influence the degradation of polymers. Structure-property correlation: discussion of the loss of physical properties following the change in the chemical structure of a polymer. Degradation mechanisms. 3. THE SERVICE LIFE OF POLYMERS (II): OXIDATION and STABILIZATION. Definition of oxidation, reaction conditions, effects and radical chain mechanism. Antioxidants and chain inhibitors. Preventive action. 4. ASSESSMENT OF POLYMER THERMAL DEGRADATION AND OXIDATION: TRADITIONAL VS. ADVANCED ANALYTICAL METHODS. i) Traditional analytical methods for investigating the thermal degradation of polymers (TGA-FTIR, TGA-MS): case studies, versus ii) Advanced analytical methods for investigating the thermal degradation of polymers (FAST-TGA, flash pyrolysis): case studies. 5. THE SERVICE LIFE OF POLYMERS (III): FIRE SAFETY WITH TRADITION. General concepts on combustion and flame retardancy of polymers. Definitions of: polymer combustion cycle, hazard and risk associated with a fire, and flame retardant. Description of the different action mechanisms of flame retardants: TRADITIONAL FLAEM RETARDANTS: i) inorganic-, carbonate-, and boron-based flame retardants; ii) halogen-based flame retardants, iii) phosphorus-based flame retardants, and iv) intumescent flame retardants. 6. THE SERVICE LIFE OF POLYMERS (III): FIRE SAFETY WITH NANOTECHNOLOGY. Polymeric nanocomposites and nanocoatings. 7. THE SERVICE LIFE OF POLYMERS (III): FIRE SAFETY WITH BIO-BASED AND BIO-INSPIRED POLYMERS. Bio-derived and bio-inspired flame retardants. 8. ASSESSMENT OF POLYMER COMBUSTION. Advanced analytical methods for investigating polymer combustion (oxygen consumption cone calorimetry, flame spread and LOI tests): case studies on traditional, nanotechnological and bio-derived or bio-inspired flame retardants. 9. THE SERVICE LIFE OF POLYMERS (IV): PHOTODEGRADATION AND PHOTO-OXIDATION. General concepts on the mechanism of photoinduced degradation of polymers, natural and accelerated aging of polymers. Polymer stabilization methods concerning photodegradation. Case studies on aging by light exposure of plastics. 10. ASSESSMENT OF POLYMER PHOTODEGRADATION AND PHOTO-OXIDATION. Advanced analytical methods for investigating the photo-degradation of polymers (xenon tests): case studies. 11. THE SERVICE LIFE OF POLYMERS (V): DEGRADATION INDUCED BY HIGH-ENERGY RADIATIONS. Definition and mechanism of polymer degradation induced by exposure to high-energy radiations, stabilization and protective actions. 12. THE SERVICE LIFE OF POLYMERS (VI): MECHANICAL DEGRADATION. Definition and mechanism of polymer degradation induced by mechanical stress. Self-healing polymers. 13. THE ENDLIFE OF POLYMERS (I): RECYCLE, REUSE AND VALORIZATION. Definition of polymer recycling by chemical and mechanical approaches and energy production; circular economy 14. THE END-LIFE OF POLYMER (II): BIODEGRADATION AND COMPOSTABILITY. Definition, classification and physico-chemical properties of biodegradable polymers and biodegradable plastics. Description of the biodegradation and composting mechanisms. Case studies related to the durability of (bio)degradable polymers. 15. MICROPLASTICS IN THE ENVIRONMENT: an underestimated or overemphasized problem?
Prerequisites for admission
The course is intended for students who have attended fundamental courses in chemistry and industrial chemistry who plan to acquire advanced knowledge on the degradation phenomena affecting a polymer during the different phases of its life, from synthesis to processing and disposal. Prerequisites: basic knowledge of organic and physical chemistry, and polymer chemistry.
Frontal lessons with the aid of slides and audio-visual systems.
· Slides of the course accompanied by videos dedicated to some topics of the course · Scientific papers and reviews on specific topics · "Thermal degradation of polymeric materials" of Krzysztof Pielichowski and James Njuguna, edited by Rapra Technology (2005) · "Flame Retardancy of Polymeric Materials" of C. A. Wilkie and A. B. Morgan, edited by CRC Press (2010) · "Fire Retardancy of polymeric materials" of A.R. Horrocks and D. Price, edited by CRC Press (2013) · "Polymer Photodegradation: Mechanisms and Experimental Methods" of Jan F. Rabek, edited by Chapman & Hall (1985) · "Handbook of Biodegradable Polymers. Synthesis, Characterization and Applications" of A. Lendlein and A. Sisson, edited by Wiley (2011)
Assessement methods and criteria
Assessment method: final written test with open questions. No intermediate tests are planned. Students will be asked to answer general questions regarding all the topics covered in the course. Test duration: normally 2.5 hours. Score will vary in the range 18 to 30 out of 30 and will be proportional to the number of correct answers. The test results will be communicated by e-mail a few days after the exam and registration will be conditioned on acceptance by the student.