Wood flour/-poly(methyl methacrylate)/capric acid polymer composites as form-stable phase change materials for thermal energy management

Abstract

This study focuses on the preparation and characterization of wood flour (WF)/polymethyl methacrylate (PMMA)/capric acid (CA) composite form-stable phase change materials (PCM) prepared by PMMA modification method, with WF selected as the support material. The surface morphology (scanning electron microscopy SEM), chemical structure (Fourier transform infrared spectrometer, FTIR), crystalline structure (X-ray diffraction, XRD), phase change properties (differential scanning calorimeter, DSC), thermal stability (thermogravimetric analysis, TGA) of the prepared WF/PMMA/CA composite form-stable PCMs were investigated. SEM analysis demonstrates that the wood surfaces were coated with CA and PMMA. As the PMMA ratio on the surfaces increased, the amount of leaching decreased. FTIR and XRD results suggested that the structure of the PMMA polymer is also seen in the prepared composite materials. There was no chemical reaction but only physical interactions between WF and CA. The generated WF/PMMA/CA composite PCMs exhibited high latent heats and an appropriate phase change temperature range; in particular, the WF/PMMA/CA (1/1/2)'s highest latent heats throughout the melting and freezing processes were 95.08 J/g and 91.29 J/g, respectively. Using higher proportions of CA provides more energy storage capacity; however, the contribution of PMMA further enhances this effect, strengthening the energy storage performance. Thermal conductivity increased by 63.9 % in WF/PMMA/CA (1/1/2).