Fig. 3: Pyrolysis behavior under air atmosphere.

a–c TGA and DTG curves of K-salts filled FPUF. d The bar graphs of initial pyrolysis temperature (T5%) of K-salts filled FPUF. e The bar graphs of the mass loss of K-salts filled FPUF during 260–320 °C. f Three-dimensional distribution of T5%, mass loss during 260–320 °C, and LOI values of K-salts filled FPUF (x, y, z = T5%, mass loss during 260–320 °C, LOI, respectively).