Recent Trends of Recycling and Upcycling of Polymers and Composites: A Comprehensive Review
Christina Podara,
Stefania Termine,
Maria Modestou,
Dionisis Semitekolos,
Christos Tsirogiannis,
Melpo Karamitrou,
Aikaterini-Flora Trompeta,
Tatjana Kosanovic Milickovic,
Costas Charitidis
Affiliations
Christina Podara
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Stefania Termine
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Maria Modestou
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Dionisis Semitekolos
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Christos Tsirogiannis
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Melpo Karamitrou
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Aikaterini-Flora Trompeta
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Tatjana Kosanovic Milickovic
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
Costas Charitidis
Research Lab of Advanced, Composite, Nano Materials & Nanotechnology (R-NanoLab), School of Chemical Engineering, National Technical University of Athens, 9 Heroon, Polytechniou St., Zografos, 157 80 Athens, Greece
This review article gathers the most recent recycling technologies for thermoset and thermoplastic polymers. Results about existing experimental procedures and their effectiveness are presented. For thermoset polymers, the review focuses mainly on fibre-reinforced polymer composites, with an emphasis on epoxy-based systems and carbon/glass fibres as reinforcement, due to the environmental concerns of their end-of-life management. Thermal processes (fluidised bed, pyrolysis) and chemical processes (different types of solvolysis) are discussed. The most recent combined processes (microwave, steam, and ultrasonic assisted techniques) and extraordinary recycling attempts (electrochemical, biological, and with ionic liquids) are analysed. Mechanical recycling that leads to the downgrading of materials is excluded. Insights are also given for the upcycling methodologies that have been implemented until now for the reuse of fibres. As for thermoplastic polymers, the most state-of-the-art recycling approach for the most common polymer matrices is presented, together with the appropriate additivation for matrix upcycling. Mechanical, chemical, and enzymatic recycling processes are described, among others. The use of fibre-reinforced thermoplastic composites is quite new, and thus, the most recent achievements are presented. With all of the above information, this extensive review can serve as a guide for educational purposes, targeting students and technicians in polymers recycling.
