The hybrid polyhydroxyurethane materials synthesized by a prepolymerization method from CO2-sourced monomer and epoxy

Thermal and UV Curable Formulations of Poly(propylene glycol)-Poly(hydroxyurethane) Elastomers toward Nozzle-Based 3D Photoprinting

In this work, isocyanate-free formulations for poly(propylene glycol) polyurethane elastomers are studied. These formulations are based on poly(propylene glycol) end-capped by CO2-sourced cyclic carbonate (bisCC PPG) macromonomers able to react with amines leading to poly(hydroxyurethane)s. In order to obtain covalent networks, two curing approaches are studied. First, the direct thermally activated cross-linking of bisCC PPG with a mixture of various aliphatic or aromatic diamines and a triamine is investigated, and in particular the nature of the diamine on the mechanical properties. In the second approach, UV-activated formulations are developed by reacting bisCC PPG with allylamine followed by the addition of a trithiol by photoactivated thiol-ene reaction. The swelling tests show that both systems provide highly cross-linked polymer networks and complementary characterizations highlighted excellent mechanical properties. Thanks to the fast curing and adapted viscosity of the developed photoactive formulation, the latter was found suitable for use as a photoresin for 3D printing as demonstrated by printing a vaginal ring by a nozzle-based photoprinter.

Insight into the Varying Reactivity of Different Catalysts for CO2 Cycloaddition into Styrene Oxide: An Experimental and DFT Study

The cycloaddition of CO₂ into epoxides to form cyclic carbonates is a highly sought-after reaction for its potential to both reduce and use CO₂, which is a greenhouse gas. In this paper, we present experimental and theoretical studies and a mechanistic approach for three catalytic systems. First, as Lewis base catalysts, imidazole and its derivatives, then as a Lewis acid catalyst, ZnI₂ alone, and after that, the combined system of ZnI₂ and imidazole. In the former, we aimed to discover the reasons for the varied reactivities of five Lewis base catalysts. Furthermore, we succeeded in reproducing the experimental results and trends using DFT. To add, we emphasized the importance of non-covalent interactions and their role in reactivity. In our case, the presence of a hydrogen bond was a key factor in decreasing the reactivity of some catalysts, thus leading to lower conversion rates. Finally, mechanistically understanding this 100% atom economy reaction can aid experimental chemists in designing better and more efficient catalytic systems.

Biodegradable Natural Rubber Based on Novel Double Dynamic Covalent Cross-Linking

In this paper, biodegradable epoxidized natural rubber containing cyclic carbonate groups (CNR) was prepared by the reaction between epoxidized natural rubber (ENR) and carbon dioxide. Dynamic disulfide bonds and a boronic ester structure were successfully constructed and then the cross-linking network was formed by the thermally initiated “click” reaction between thiol groups of the cross-linker and the residual epoxy groups of ENR. As a result of the exquisite double dynamic covalent structure, the material exhibits high self-healing efficiency. Moreover, by virtue of the cyclic carbonate structure of the CNR, the natural rubber was confirmed to be biodegradable according to the biodegradable measurement. To the best of our knowledge, natural rubber with biodegradable and self-healing characteristics was obtained for the first time.

Synthesis and structural characterization of bio-based bis(cyclic carbonate)s for the preparation of non-isocyanate polyurethanes

Full chemical structure characterization of cyclic carbonates from diepoxides synthesized using sustainable bio-based polyols with different molecular weights and carbon dioxide.

Studies on the effects of different multiwalled carbon nanotube functionalization techniques on the properties of bio-based hybrid non-isocyanate polyurethane

Different types of surface modification on MWCNTs can affect the thermal stability and water absorption of composites.

Non-isocyanate polyurethane/epoxy hybrid materials with different and controlled architectures prepared from a CO2-sourced monomer and epoxy via an environmentally-friendly route

A series of polyurethane/epoxy hybrid materials with different and controlled architectures were prepared by a non-isocyanate route. The properties and architectures of materials were regulated by adjusting the ratio and type of amine.