Long-term stability and water vapor induced degradation of physico-chemical properties of XPS and PF

Insulation plays a pivotal role in enhancing the energy efficiency of buildings, offering an effective means to reduce heat transfer and optimize energy consumption. However, the long-term performance of foamed plastic insulation is threatened by moisture-induced degradation of thermal performance. This study aims to clarify the degradation mechanism of extruded polystyrene foam (XPS) and phenolic-based foam (PF) by characterizing their physico-chemical properties, including morphological, polymer network, and chemical changes. The results obtained as follows: i) XPS confirmed that the cell structure changed heterogeneously over-time degradation. No significant changes were observed in water vapor degradation. ii) PF polymerized from residues during over-time degradation, which affects its cell structure. We confirmed that hydrolysis occurs from water vapor degradation, which may affect thermal conductivity. The changes in properties due to insulation degradation provided by our research contribute to the basis of countermeasures against degradation.