Bio based PUR-PIR foams thermal degradation (TG) and isoconversional kinetics

In the present work, we perform a thorough thermogravimetric (TG) analysis of the bio-based polyurethane – polyisocyanurate (PUR-PIR) foams in both nitrogen and oxygen atmosphere. A sustainable element of the foam was a biopolyol obtained via acid-catalyzed liquefaction of Zostera Marina and Enteromorpha Algae biomass. Based on isoconversional analysis and apparent activation energies several conclusions were obtained. In contradiction to the common understanding, biopolyol based foams exhibit enhanced stability in both oxidative atmosphere and in nitrogen compared to purely petrochemical foams. Relationships between thermal stability and structures of the foams were established. Enhanced stability of bio-based foams in oxygen was attributed to two factors. First is an increased cross-linking density due to higher hydroxyl number of biopolyol compared to petrochemical one. Secondly the presence of aromatic compounds in the structure of polyols that come from lignin or aromatic ketones have the capacity to further enhance thermal stability