Development of polymeric insulating foams for low-temperature thermal energy storage applications

Refrigeration plays an important role in several sectors in 21st-century life, such as food, air conditioning, healthcare, industry, and energy. In food industry it plays a vital role for reducing the post-harvest losses and in the preservation of food products. In this paper different amounts of a microencapsulated paraffin having a melting temperature of -10 degrees C were used as phase change material (PCM) for the preparation of multifunctional rigid polyurethane foams (PUF) for refrigeration applications. The processability issues, the microstructural and thermo-mechanical properties of the resulting panels were comprehensively investigated. Morphological analysis evidenced a tendency of the incorporated PCM to damage the original closed cell structure of the PUF, and a fully open-cell microstructure was obtained for PCM contents higher than 20 wt%. Differential scanning calorimetry (DSC) evidenced a proportional correlation between the PCM concentration while the thermal energy storage efficiency of the prepared panels was also confirmed by monitoring the trend of the inner temperature in cubic specimens subjected to programmed heating and cooling ramps. Concerning the mechanical response, flexural tests evidenced that the stiffness of the foams was not substantially influenced by the PCM content, while a heavy drop of the failure properties was detected.