Soy Oil‐Based Rigid Polyurethane Biofoams Obtained by a Facile One‐Pot Process and Reinforced with Hydroxyl‐Functionalized Multiwalled Carbon Nanotube

Highly conductive, thermally insulating, and three-dimensional (3D) macromolecular network-structured nanocomposite biofoams with very low density were designed from soy oil-based polyurethane (PU) and hydroxyl-functionalized multiwalled carbon nanotubes (MWCNT-OH) using a facile one-pot process with water as the sole blowing agent. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Fourier Transform Infrared spectroscopy (FTIR) analyses revealed homogeneous dispersion as well as interaction or reaction of MWCNT-OH with the PU biofoam matrix or a polymeric methylene diphenyl diisocyanate (MDI) to form a 3D macromolecular network structure. Mechanical properties and electrical conductivity were remarkably enhanced with the increase of MWCNT-OH. Dynamic mechanical analysis and thermogravimetric analysis results showed that all the nanocomposite PU biofoam products had good thermal stability properties. Hence, the prepared nanocomposites hold promise as rigid biopolyurethane (BioPU) foams, serving the needs of the conductive composite material fields.