Recycling alginate composites for thermal insulation

Matteo Cibinel; Giorgia Pugliese; Davide Porrelli; Lucia Marsich; Vanni Lughi

doi:10.1016/j.carbpol.2020.116995

Recycling alginate composites for thermal insulation

Carbohydr Polym. 2021 Jan 1:251:116995. doi: 10.1016/j.carbpol.2020.116995. Epub 2020 Sep 6.

Authors

Matteo Cibinel¹, Giorgia Pugliese², Davide Porrelli³, Lucia Marsich², Vanni Lughi²

Affiliations

¹ Department of Engineering and Architecture, University of Trieste, Via Valerio 6/1, 34127, Trieste, Italy. Electronic address: matteo.cibinel@phd.units.it.
² Department of Engineering and Architecture, University of Trieste, Via Valerio 6/1, 34127, Trieste, Italy.
³ Department of Medicine, Surgery and Health Sciences, University of Trieste, Piazza dell'Ospitale 1, 34125, Italy.

PMID: 33142565
DOI: 10.1016/j.carbpol.2020.116995

Abstract

We present a new method for the total functional recycling of alginate-based composite materials made via ionotropic gelation. The original material, an alginate/fiberglass foam with thermal insulation characteristics, was produced following a patented process in which fiberglass waste is embedded into the polyanionic gel matrix, and the resulting compound is then freeze-dried. The functional recycling is carried out by disassembling the ionic matrix - which is initially formed by the interaction between a cation (e.g. calcium) and the negatively charged alginate backbone - with the use of a chelator (Ethylenediaminetetraacetic acid disodium salt) with a high affinity for the cations, thus obtaining a homogeneous solution. An ionotropic gel can then be re-formed upon deactivation of the chelating activity under mild acid conditions. We managed to maintain or improve the thermal, mechanical and acoustic performances of the original material and we successfully tested the possibility of multiple recycling cycles.

Keywords: Alginate; Chelation; Composite; EDTA; Recycling; Thermal insulation.