Fig. 4. Mechanism of catalytic decomposition for CO₂ release.

a–c The three-dimensional spectra of pyrolysis products of K-formate and K-malate filled FPUF collected from TGA coupled with FTIR under air atmosphere. d Gaseous phase products cumulative intensity under air atmosphere at 260–320 °C, and the cumulative intensity was obtained by integrating the normalized absorbance curve of K-salt filled FPUF during 260–320 °C. e DSC curves of K-formate and K-malate filled FPUF under air atmosphere. f Thermal decomposition average apparent activation energy (Eα) calculated from Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. g Mechanism of CO₂ generation from early decomposition of polyurethane catalyzed by K-salt.