CO₂-Blown Nonisocyanate Polyurethane Foams

Abstract

Polyurethane (PU) foams are produced from toxic, petrochemical- and phosgene-derived isocyanates. Although nonisocyanate polyurethane (NIPU) has shown promise as a replacement for traditional PU, the synthesis of NIPU foams has not been widely studied due to the difficulties in replicating the foaming process of PU, in situ CO2 production through the hydrolysis of isocyanates. Hereby, we report the synthesis of amine-CO2 adducts and their CO2 adsorption–desorption characteristics under different conditions. The results show that the amine-CO2 adducts can exhibit up to 87% CO2 desorption at 60 °C after aminolysis with cyclic carbonate. The amine-CO2 adduct is used as both a foaming agent and a comonomer to obtain low-density foams (0.203–0.239 g·cm–3) after heating at 50–60 °C for 24–48 h. This marks the successful synthesis of in situ CO2-blown NIPU foams using an amine-CO2 adduct.

Microwave-Induced Construction of Flame-Retardant TPU Foams with Adjustable Sensitivity for Piezoresistive Sensing

“…On the other hand, a higher proportion of crystals melted under higher temperature, which was conducive to bubble growth, finally yielding a larger number of cells with an average cell size of 58.1 μm (Figure f). When the microwave irradiation power further increased to 100%, the increased surface temperature not only led to the decrease in the crystallization of TPU but also resulted in a significant decrease in melt strength, thus causing the pore structure to be prone to collapse with a relatively small number of bubbles with an average diameter of 56.2 μm (Figure g). − The XRD test results of BP and TBC are shown in Figure h, and the characteristic peaks of BP in TBC composites indicated the successful compounding of the materials. , For an in-depth analysis of the surface chemical properties of TBC, X-ray photoelectron spectroscopy (XPS) testing was conducted (Figure i). The XPS overview spectrum displayed typical C, N, O, and P elements derived from BP, CNTs, and TPU.…”

Nanocomposite Foams of Polyurethane with Carbon Nanoparticles—Design and Competence towards Shape Memory, Electromagnetic Interference (EMI) Shielding, and Biomedical Fields

“…Remarkable properties of polyurethane sponges led to applications in aerospace, automotive, packaging materials, biomedical, etc. [40][41][42]. Lately, numerous nanoparticles have been filled in polyurethane matrices to design nanocomposite foams [43,44].…”

“…packaging materials, biomedical, etc. [40][41][42]. Lately, numerous nanoparticles have been filled in polyurethane matrices to design nanocomposite foams [43,44].…”

Foam-to-Elastomer Recycling of Polyurethane Materials through Incorporation of Dynamic Covalent TAD–Indole Linkages

“…Already around 70 years ago, Offenbach and Tobolsky reported a stress-relaxation character under specific temperature and pressure. , Besides incorporation of intrinsically reactive dynamic groups, ,,, numerous attempts to increase the internal dynamicity of PU-elastomers are reported. ,,– Another chemorheological study , toward PU materials containing free hydroxyl groups (polyhydroxyurethanes) contributed to the idea of recyclable PU materials. For example, Dichtel and Fortman studied a reprocessable PU-like material without the aid of an external chemical entry. , Since the materials were obtained starting from cyclic carbonates, the pioneering work contributed to nonisocyanate polyurethane (NIPU) foam literature. ,,,– …”