Hydrophobic Modification of the α‐Hemihydrate Phosphogypsum (α‐HH) Surface by Myristic Acid

Abstract

AbstractPhosphogypsum is widely used as a filler. However, gypsum fillers exhibit poor water resistance, compromising the performance of subsequent products. To address this issue, we modified α‐hemihydrate phosphogypsum (α‐HH) with myristic acid (ΜΑ), a low surface energy material used to prepare super hydrophobic (SHP) surfaces. The MA concentration, temperature, and modification time were optimized using a Box‐Behnken experimental design method. The surface properties, microstructure, and thermal stability of the modified powders were characterized using contact angle measurements, X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR) spectroscopy, Raman spectrum, X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM‐EDS), and thermal gravimetry‐differential scanning calorimetry (TG‐DSC). Additionally, we discussed the hydrophobic modification mechanism of the modified α‐HH. The modified α‐HH/MA prepared with 11.0×10−4 mol L−1 MA at 60 °C for 60 min exhibited high hydrophobicity. During modification, MA bound to the calcium ions on the surface of α‐HH to form calcium myristate, thereby forming a hydrophobic film. The thermal stability of α‐HH was improved by MA modification. The modified powder maintained high hydrophobicity even at 250 °C.