Impact of various Mg(OH)\(_{2}\) morphologies on hydrophobicity, mechanical, and physical properties of polyurethane nanocomposite

Polyurethane (PU) is one of the best polymer coatings due to its wide range of advantages such as easy fabrication, lightness, non-toxicity, durability, adhesion, flexibility, and strength. However, some of its drawbacks make it a suitable choice for the manufacturing of nanocomposites to enhance its properties. Hydrophobicity and flame retardancy are two of the most crucial characteristics of a polymer nanocoating. Magnesium hydroxide (MH), with its ability to be produced in a multitude of morphologies and exceptional properties, especially in flame retardancy, has always attracted the interest of researchers. One of the best methods for synthesizing high-purity, controlled-size, and controlled-shape nanoparticles is the hydrothermal technique. In this paper, magnesium chloride and sodium hydroxide were utilized as raw materials to synthesize four different morphologies of MH, such as plate, flake, spherical, and disk, functionalized using 3-Aminopropyl triethoxysilane (APTES). In the following, PU nanocomposites were fabricated by drop casting method including 3 % w.t. of different synthesized MH. The influence of each morphology on different properties of PU/Mg(OH)\(_{2}\) was then investigated using different analyses such as spectroscopy, mechanical, and hydrophobicity tests. The observations indicated that different surface topography would result from the presence of nanoparticles with various morphologies on the nanocomposite’s surface. Extremely high water contact angles were attained as a result of the surface roughness, revealing the super hydrophobic behavior of the produced nanocoatings. Also, the presence of MH in PU matrix improved the mechanical properties of the nanocomposite, depending on the aspect ratio and particle size.