This paper proposes more sustainable alternatives for the synthesis of high thermal performances phenolic networks. Terephthalaldehyde (TPA), a non-toxic aromatic dialdehyde, was selected to replace formaldehyde. Phenol was in turns replaced with bio-based and non-toxic phenolic building blocks: resorcinol as model for tannins, guaiacol which is easily accessible from lignin and tyrosol from olive oil mill wastewaters. The prepolymerization was performed under mild conditions (ethanol, T ≤ 100 °C). The liquid prepolymers were characterized by NMR, IR, MALDI-ToF and rheology. The curing behavior of these formulations was assessed by DSC and IR spectroscopy. An advanced isoconversional analysis of the DSC data allowed the determination of crosslinking activation energies. Furthermore, a multiple-step mechanism of TPA crosslinking was proposed with strong evidences. The thermo-mechanical properties of cured networks were characterized using DMA, showing high crosslink densities and fairly elevated glass transition temperatures. Finally, it has been proven that these new thermosets display very high thermal performances under pyrolysis conditions (TGA). TOCNew sustainable high-performance phenolic thermosets are synthesized from non-toxic and potentially biobased chemicals. We report understanding of curing mechanism and outstanding performances of networks.

Rare-earth elements (REEs) are involved in most high technology devices and have become critical for many countries. The progress of processes for the extraction and recovery of REEs is therefore essential. Liquid–solid extraction methods are an attractive alternative to the conventional solvent extraction process used for the separation and/or purification of REEs. For this purpose, a solid-phase extraction system was investigated for the extraction and valorization of REEs. Ion-exchange resins were synthesized involving the condensation of terephthalaldehyde with resorcinol under alkaline conditions. The terephthalaldehyde, which is a non-hazardous aromatic dialdehyde, was used as an alternative to formaldehyde that is toxic and traditionally involved to prepare phenolic ion-exchange resins. The resulting formaldehyde-free resole-type phenolic resins were characterized and their ion-exchange capacity was investigated in regard to the extraction of rare-earth elements. We herein present a promising formaldehyde and phenol-free as a potential candidate for solid–liquid extraction REE with a capacity higher than 50 mg/g and the possibility to back-extract the REEs by a striping step using a 2 M HNO3 solution.