High-Toughness and High-Transparency Recyclable Poly(vinyl alcohol)-Based Organic-Inorganic Composite Membranes

In this paper, a recyclable and sustainable organic-inorganic composite membrane (hereafter referred to as PPS) was synthesized by solvent casting method using poly(vinyl alcohol) (PVA), phosphoric acid (H₃PO₄), and sodium silicate (Na₂SiO₃) as raw materials, aiming to reduce or even replace the use of conventional plastics. The effects of the concentrations of H₃PO₄ and Na₂SiO₃ on the membrane properties were investigated, and the results showed that the PPS material has a dense structure, good thermal stability, tensile strength up to 48.36 MPa, and elongation at break up to 520.44%. Compared with PVA, the tensile strength and elongation at break were increased by 1.64 and 5.79 times, respectively, and its hydrophilicity was reduced by 27%. The strength and stability of the material were improved through hydrogen bonding and esterification between the compounds, and the toughness and hydrophobicity of the material were enhanced. In addition, the disconnected composite membrane can be bonded by wet pressing and can be recycled to recast into a membrane after dissolving in water at 80 °C. The manufacture of PPS by solvent casting is simple, does not produce large amounts of toxic gases in production, is recyclable and sustainable, and meets the requirements of industrial environmental protection.