Water-in-oil emulsion templated polyurethanes with uniform porosity

• Published in: Polymer (Guilford) Vol. 301; p. 127030
• Main Authors: Dikella, D.G.N. Vindya, Dalton, Emily, Horvath, Jonathan, Ayres, Neil
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 02.05.2024
• Subjects: PolyHIPE; Polyurethane; Porous polymer; Polyurethane; PolyHIPE; Porous polymer
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2024.127030

Porous PU foams have been receiving great attention because of their low density, lightweight, and high surface area. However, preparing PU foams with controlled porosity, pore size, and pore morphology is often difficult with commonly used methods like gas blowing. Here, highly controllable porous PU with small, uniform pore morphology and tunable material properties have been synthesized using water-in-oil polymerized high internal phase emulsion (PolyHIPE) templating and photoinitiated thiol-ene reactions between vinyl-functionalized polyurethane prepolymers and thiol-functionalized crosslinkers. The PolyHIPEs exhibited highly interconnected open-cell structures with pore sizes ranging from 5 to 10 μm. The storage moduli and elastic moduli of PU polyHIPEs derived from flexible HDI-PUs were low compared to stiff IPDI-PU based polyHIPEs. Furthermore, the storage moduli of relatively soft HDI-PU polyHIPEs were affected by the stoichiometric ratio of thiol crosslinker and vinyl-PU whereas no considerable effect on the stiffer IPDI-PU based polyHIPEs. In summary, this work presents an approach to synthesize porous polyurethane polyHIPEs with potential applications in aerospace, automotive, and biomedical industries. [Display omitted] •Polyurethane emulsion templated materials were prepared in a water-in-oil emulsion without mm-sized pores.•The absence of large pores was a result of using prepolymers cured using a thiol-ene reaction.•The materials properties of the polyHIPEs are controlled through the chemistry of the polyurethane.