Facile fabrication and modification of polyacrylate/silica nanocomposite latexes prepared by silica sol and silane coupling agent

Polyacrylate/silica nanocomposite latexes were prepared by silica sol and facilely modified with a silane coupling agent γ-methacryloxypropyltrimethoxysilane (KH-570) aimed at reinforcing the interaction between silica nanoparticles and latex particles in a convenient way. The effects of silica sol and KH-570 amounts on the performance of latexes and films are discussed. Particle size and morphology tests demonstrated that the silica nanoparticles could form hydrogen bond interactions between latex particles, and thus influence the rheological properties of latexes. Tensile measurements and SEM photographs showed the reinforcing and toughening roles of silica nanoparticles. SEM images also indicated that the addition of silica sol increased the roughness of films, which resulted in the increase of hydrophilic silanol groups on the film surface and the decrease of water resistance of latex films. The latex films retained good adhesion force, flexibility, and impact resistance even when the silica sol content was as much as 25%. TGA data revealed that the incorporation of silica sol enhanced the thermal stability of the films. After introducing KH-570, the particle size increased with the increase of the amount of KH-570. Moreover, the addition of KH-570 improved the water resistance and maintained other properties of the latex films appropriately.