Wood adhesive based on polyvinyl alcohol stabilized polyvinyl acetate, vinyl neodecanoate, vinyl trimethoxy silane, and N-methylol acrylamide copolymer emulsion: synthesis and characterization

To improve a polyvinyl acetate (PVAc) emulsion-based glue's water resistance, this study aims to offer it a controlled ability for cross-linking. Emulsion polymerization was used to synthesize PVAc-vinyl neodecanoate-vinyl trimethoxy silane-n-methyl acrylamide poly (VAc-VeoVa10-VTMO-NMA) copolymers with polyvinyl alcohol (PVA) stabilization. Using Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC), the copolymerization and glass transition temperatures (Tg) of film were analyzed. To assess the effectiveness of the cross-linked emulsions-based adhesive, the tensile shear strength of wood joints under dry and wet conditions was measured in compliance with the EN 204 and EN 205 standards. The experimental results showed that the copolymer-based poly (VAc-VeoVa10-VTMO-NMA) adhesive significantly increased Tg and film hardness when compared to poly (VAc-VeoVa10-VTMO). Tensile shear strength increased by ∼9% in a dry environment after 24 h of bonding (per EN 204) and by ∼18% in a wet environment with poly (VAc-VeoVa10-VTMO-NMA) adhesive, in comparison to a poly (VAc-VeoVa10-VTMO) adhesive. A contact angle test confirmed that cross-linked poly (VAc-VeoVa10-VTMO-NMA) copolymer adhesives performed somewhat better in wet and heat-resistant conditions than cross-linked poly (VAc-VeoVa10-VTMO) copolymer adhesives. The method proposed provides an easy-to-use route to emulsions with enhanced water resistance and bonding strength by including NMA as a reactive co-monomer.