This article describes the synthesis of new cyclic compounds able to react with amines to get nonisocyanate polyurethanes (NIPUs). The contribution of the most studied five‐membered cyclic carbonate was compared to five‐membered cyclic dithiocarbonate analogous and to a six‐membered cyclic carbonate. Difunctional reactive species were obtained by a simple substitution reaction or an efficient thiol–ene coupling reaction. The products, obtained with high yields, were characterized by 1H NMR, 13C NMR, and Fourier tansform infrared spectroscopy analysis. The dicyclocarbonates were then used to synthesize NIPUs by step growth polymerization with several diamines. These materials exhibited glass transition temperatures from 19 to −29 °C, molar mass from 1800 to 20,400 g mol−1, and a 20% mass loss temperature (Td = 20%) between 249 and 296 °C. Such materials are interesting candidates for coating applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3284–3296

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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.

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