Poly(vinyl alcohol)/fatty acid blends for thermal energy storage

This article is aimed to prepare the blends of poly( vinyl alcohol) ( PVA) with fatty acids (lauric, myristic, palmitic, and stearic acids) as shape-stabilized phase change material ( PCM), to prove the miscibility of fatty acids with the PVA by microscopic investigation and infrared ( IR) spectroscopy, and to measure their melting temperature and the latent heat of fusion by differential scanning calorimetry ( DSC) analysis methods. In the blends, the fatty acids, which are dispersed in the solid network of the polymer, act as latent heat thermal energy storage (LHTES) material during its solid-liquid phase change when the polymer ( PVA) has function of supporting material because of its structural strength. Therefore, the shape-stabilized fatty acids can keep the same shape in a solid shape without leakage of liquid fatty acids by aid of PVA in solid state. The maximum mixture ratio for all fatty acids in the shape-stabilized form was found as 50 wt%. By using DSC analysis method, the melting temperatures and latent heats of the shape-stabilized lauric, myristic, palmitic and stearic acids were determined as 39.8, 50.2, 56.2, and 67.4 degrees C and 96.4, 105.3, 121.6, and 132.6 J/g, respectively. The results indicate that the PVA/fatty acids blends as shape-stabilized PCM have great potential for passive solar LHTES applications in terms of their satisfactory thermal properties and utility advantage of without encapsulation.