Fossil-fuel-based polyurethanes (PUs) have been studied and used extensively for several decades. Recently, environmental and economic concerns have driven major efforts to eliminate the use of isocyanate and substitute fossil-fuel-based precursors with renewable, biobased ones. Aminolysis of cyclic carbonates and thio(cyclic carbonate)s generate non-isocyanate polyhydroxyurethanes (PHU) and polythiourethanes (PTU), respectively. Cyclic carbonates (CCs) or thio(cyclic carbonate)s (TCCs) are synthesized through the fixation of CO₂ or CS₂ onto epoxides; the usage of epoxide building blocks opens up a library of biobased precursors. However, commonly reported biobased epoxides are food-based, which leads to potential competition between polymer production and the food industry. Considering the lack of study in non-food biobased materials, herein, we explored and selected non-food biobased epoxides; using the epoxides’ reactivity towards both CO₂ and CS₂, we prepared both CCs and TCCs that were subsequently transformed into non-food biobased PHUs and PTUs. Specifically, by selecting CCs with different molecular structures, we designed and synthesized non-food biobased linear segmented PHUs with various properties, e.g., thermoplastic elastomers, vibrational and acoustic noise damping materials, etc. Using the same epoxides, we also synthesized network PHUs and network unconventional PTUs. We demonstrated their robustness, reprocessability, promising mechanical performance, and excellent high-temperature creep resistance. In addition, we also demonstrated the existence of self-activated dynamic disulfide linkages that can enhance the mechanical property and creep resistance. Finally, we synthesized non-food biobased self-blowing PHU foams with tunable properties.

Nathan Purwanto

Appearances