Presence of GO in PU muffles discharge of heat, smoke and CO and CO2 into atmosphere. The maximum improvement in mechanical properties achieved by including 2.0 wt- of GO in PU framework, indicating an increase in tensile stress and elongation at break of 155.1 and 27.7 compared to PU. Primary temperature of thermal degradation of PU/GO nanocomposite increased by 36.5°C with 3.0 wt- of GO. Charred yield of PU/GO composites augmented due to GOs� physical hindrance which limits diffusion of flammable gas. Muffling effect of GO in danger of flame and smoke exposure of polymer composites decreased by introduction of 3.0 wt- of GO. Uniform distribution of GOs within PU matrix formed a strong, twisted route and sticky char in PU/GO composites and delayed thermal deterioration process. Thereby, this work introduces an important method for improving thermal stability and fire protection of PU providing an effective application for coating industry. © 2020 Institute of Materials, Minerals and Mining Published by Taylor & Francis on behalf of the Institute.