TG/DTA-FTIR as a method for analysis of tall oil based rigid polyurethane foam decomposition gaseous products in a low oxygen environment

Abstract

This study is an investigation of the suitability of the thermogravimetry and differential thermal analysis method coupled with Fourier Transform Infrared spectrometry (TG/DTA-FTIR) for a thermal degradation gaseous product analysis of a rigid polyurethane-polyisocyanurate (PU-PIR) foam synthesised from high functionality tall oil fatty acids (TOFA) based polyols. The FTIR spectra of the TG-generated gaseous thermal degradation products of three PU-PIR formulations with varied high functionality TO based polyol content (45, 75 and 95 pbw) and a different tier of isocyanate (NCO) indexes (110, 150, 200, 300 and 400) for each formulation were compared to the spectra of a formulation developed using conventional raw materials. The chemical bands of known chemical compounds and unknown compounds containing specific groups for the foams were evaluated; the focus was on the maximum release rate for specific chemical compounds (CO2; –NCO; H2O; CO) to determine the temperature zone values of the main thermal degradation phases. The experiments were carried out at a low oxygen environment, providing valuable data on the trends for the excretion of specific gaseous substances from the rigid PU-PUR foam that could be released in a real fire, where organic building materials that possess a porous matrix might be present and the nature of the combustion process is predominantly heterogeneous oxidation.