Thermal Black‐Infused Polyurethane Rigid Foams: Novel Formulations Toward Higher‐Performance and More Sustainable Insulation

ABSTRACT This study evaluates the effect of incorporating thermal black particles in rigid polyurethane foams. Thermal black, a low‐structure grade of carbon black, obtained by thermal decomposition of natural gas with energy recovery, was added up to 15 wt.% in foam formulations. Foam fabrication tests confirmed that thermal black particles do not inhibit foaming reactions or foam rise kinetics. It promotes slightly increased rise speed and height due to a viscosity‐reducing “fluidization” effect and its basic pH (~9.5–10.0), which favors catalyst activity. SEM analysis reveals uniform dispersion of TB particles within foam walls and a clear nucleation effect, generating finer cells and a bimodal morphology at higher loadings. Increasing thermal black content decreases the open‐cell fraction from 65% to 20% while maintaining a constant density (~40 kg/m 3 ), thereby improving dimensional stability and reducing postcuring shrinkage. Thermal conductivity remains stable between 0.0322 and 0.0327 W/m K, similar to standard construction‐grade polyurethane foams used in thermal insulation for the construction industry. Compression tests show stresses from 90 to 210 kPa at 10%–50% deformation, situating it within industrial specifications. Overall, thermal black proves to be a low‐cost, process‐friendly, and more sustainable additive for the manufacture of high‐performance rigid polyurethane insulation foams.