Preparation of novel straw-based shape-stabilized phase change materials and their effect on the properties of gypsum-based composites

A robust natural adhesive force is inherently present between the surface waxes and the plant straw. Utilizing this inherent property, the current investigation represents the pioneering development of straw-based shape-stabilized phase change materials (PCMs), achieved by incorporating capric acid (CA) PCMs to densify the matrix. The phase change gypsum composite was formulated by integrating the straw-based shape-stabilized PCMs within the gypsum matrix. The straw-based shape-stabilized PCMs not only enhanced the mechanical characteristics of the gypsum-based matrices through their biomass fiber attributes but also augmented the thermal storage capacity by functioning as PCMs. An exhaustive assessment was conducted on the physical, chemical, and thermal properties of the synthesized shape-stabilized PCMs and phase change gypsum composites. The phase change temperature and latent heat of the straw-based shape-stabilized PCMs were determined to be 26.25 °C and 133.36 J/g, respectively, with demonstrated thermal stability. Optimal mechanical properties were observed in the phase change gypsum composites when the straw-based shape-stabilized PCMs were 15 mm in length and 30 vol% in content, with flexural and compressive strengths reaching 4.52 and 12.07 MPa, respectively. The incorporation of straw-based shape-stabilized PCMs markedly diminished the thermal conductivity of the gypsum-based composites, with a thermal conductivity value of 0.4165 W/(m·K) recorded for a 40 vol% loading. The characteristics of the phase change gypsum composites fabricated in the present study render them ideally suited for deployment within the construction industry, facilitating both cleaner production methodologies and enhanced energy efficiency in buildings.