Oxidative biodegradation of a solid-solid polyether-urethane phase change material by Penicillium and Aspergillus

Polyurethane-based polymers are widely used in modern materials and as Phase Change Materials (PCMs) to improve the energy efficiency of buildings. The fungal development in buildings is favoured by the degradation of polymeric materials that act as nutritional substrates. In the present study, the fungal biodegradation of a polyether-urethane PCM (PUX1520) was investigated. Two methods of biodegradation by fungal growth on agar and in liquid media were used. Fungal growth on agar plates was monitored by measuring the surface area of each mycelium over a period of 11 days. The degradation products of PUX1520 were analysed by FT-IR and MALDI-TOF. The PUX1520 polymer had no impact on the growth of Aspergillus niger, while the growth of Penicillium sp. was increased in the presence of PUX1520. MALDI-TOF analysis revealed the existence of different soluble forms of the polymer whose concentration decreased after exposure to the fungal strains. From FT-IR analysis on the residual polymer material, an oxidation process is proposed to describe the dissociation of the urethane functions.