Dynamic Permittivity Measurement of Ground-Tire Rubber (GTR) during Microwave-Assisted Devulcanization

Autor: Rafael Pérez-Campos, José Fayos-Fernández, Juan Monzó-Cabrera, Fernando Martín Salamanca, Juan López Valentín, José Manuel Catalá-Civera, Pedro Plaza-González, Juan Rafael Sánchez-Marín
Přispěvatelé: European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Gobierno de Aragón, Consejo Superior de Investigaciones Científicas (España)
Rok vydání: 2022
Předmět:
Zdroj: Polymers; Volume 14; Issue 17; Pages: 3543
Polymers
Digital.CSIC. Repositorio Institucional del CSIC
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ISSN: 2073-4360
DOI: 10.3390/polym14173543
Popis: Many efforts are being made to find innovative ways of recycling rubber from end-of-life tires (ELTs), also called ground tire Rubber (GTR). Recycling through devulcanization allows the reintroduction of rubber back into the manufacturing industry. Such a process requires providing enough energy to break the sulfur links, while preventing damage to the polymeric chain. Microwave heating is controllable, efficient, and it does not rely on conventional heating mechanisms (conduction, convection) which may involve high heating losses, but rather on direct dielectric heating. However, to adequately control the microwave-assisted devulcanization performance, a thorough knowledge of the GTR permittivity versus temperature is required. In this work, GTR permittivity was monitored during its devulcanization. A resonant technique based on a dual-mode cylindrical cavity was used to simultaneously heat rubber and measure its permittivity at around 2 GHz. The results show sharp changes in the GTR permittivity at 160 and 190 °C. After the GTR cooled down, a shifted permittivity evidences a change in the GTR structure caused by the devulcanization process. Microwave-assisted devulcanization effectiveness is proven through time-domain nuclear magnetic resonance (NMR) measurements, by verifying the decrease in the cross-link density of processed GTR samples compared to the original sample.
This research project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement number 870,000. More information at https: //cordis.europa.eu/project/id/870000 (accessed on 27 August 2022) and https://valuerubber.eu/ (accessed on 27 August 2022). JLV and FMS also thanks the funding from Ministerio de Ciencia e Innovacion (PID2020-119047RB-I00 y PLEC2021-007793), Gobierno de Aragón (EC-22-2021) and CSIC (201860E045)
Databáze: OpenAIRE
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