In response to the growing need to reduce reliance on petrochemical feedstock and eliminate toxic isocyanates in polyurethane production, this study presents the synthesis of composite non-isocyanate polyurethane (NIPU) foams starting from a novel blend of bio-based cyclic carbonates. The resulting flexible foams are fully reprocessable and have a bio-based content ranging from 92% to 99%. They were prepared through a twostep procedure where aminolysis was first carried out between 1,4-butane diamine (BDA) and blends of carbonated soybean oil (CSBO) and bio-based butanediol bis-cyclic carbonate (BCC). A blowing reaction was induced via S-alkylation using a dithiol while diatomite was incorporated as a renewable nanoporous filler providing nucleating and reinforcing properties. The influence of the CSBO/BCC ratio on foam properties was systematically investigated through chemical, physical, thermal, and morphological analyses. A structureproperty relationship was established using an adapted Gibson–Ashby model. The resulting foams exhibited open-cell morphology with uniform cell sizes (400–600 mm) and apparent densities between 200 and 250 kg m−3. Notably, the foamswere successfully re-shaped intoflexible films via temperature-controlled compression molding, confirming their potential for recyclability and reuse. The stress-relaxation behavior of the re-processed NIPU presented a decreasing trend by increasing the relaxation time and was described by the Kohlrausch–Williams–Watts function. The activation energy was calculated according to the Arrhenius equation and was found to be 91 ± 8kJmol−1 indicating a relatively strong temperature dependence of the relaxation mechanisms. This work unlocks a new design strategy for the sustainable synthesis of fully recyclable NIPU foams, opening up new directions in green polyurethane chemistry.
Design of fully reprocessable composite non-isocyanate polyurethane (NIPU) foams from sustainable blends of cyclic carbonates
Recupido F.;Polaczek K.;Lama G. C.;Morra M.;Verdolotti L.
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2026
Abstract
In response to the growing need to reduce reliance on petrochemical feedstock and eliminate toxic isocyanates in polyurethane production, this study presents the synthesis of composite non-isocyanate polyurethane (NIPU) foams starting from a novel blend of bio-based cyclic carbonates. The resulting flexible foams are fully reprocessable and have a bio-based content ranging from 92% to 99%. They were prepared through a twostep procedure where aminolysis was first carried out between 1,4-butane diamine (BDA) and blends of carbonated soybean oil (CSBO) and bio-based butanediol bis-cyclic carbonate (BCC). A blowing reaction was induced via S-alkylation using a dithiol while diatomite was incorporated as a renewable nanoporous filler providing nucleating and reinforcing properties. The influence of the CSBO/BCC ratio on foam properties was systematically investigated through chemical, physical, thermal, and morphological analyses. A structureproperty relationship was established using an adapted Gibson–Ashby model. The resulting foams exhibited open-cell morphology with uniform cell sizes (400–600 mm) and apparent densities between 200 and 250 kg m−3. Notably, the foamswere successfully re-shaped intoflexible films via temperature-controlled compression molding, confirming their potential for recyclability and reuse. The stress-relaxation behavior of the re-processed NIPU presented a decreasing trend by increasing the relaxation time and was described by the Kohlrausch–Williams–Watts function. The activation energy was calculated according to the Arrhenius equation and was found to be 91 ± 8kJmol−1 indicating a relatively strong temperature dependence of the relaxation mechanisms. This work unlocks a new design strategy for the sustainable synthesis of fully recyclable NIPU foams, opening up new directions in green polyurethane chemistry.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
