Chitosan was used to introduce formaldehyde adsorption abilities into an emulsion binder for interior finishing coatings. Chitosan-hybridized acrylic emulsions were prepared by two methods. To produce stable chitosan-hybridized acrylic emulsions, the pre-emulsion dropping method is superior to the monomer dropping method. The adsorption performances for formaldehyde in chitosan-hybridized acrylic resin films increased with increasing chitosan contents; the films also had adsorption abilities for hydrogen sulfide and ammonia. Tensile strengths and elongation at breaking points decreased with increasing chitosan contents. Interior finishing coatings made from chitosan-hybridized acrylic resin emulsions have the qualities necessary for an interior finishing coating and showed excellent adsorption abilities for formaldehyde.

ABSTRACT:To design an organic-inorganic composite material with colloidal silica as the inorganic component, an acrylic resin emulsion and an organic silane hybridized acrylic resin emulsion were prepared by emulsion polymerization. The organic-inorganic composite films were prepared by blending the emulsion and the colloidal silica. The contact angles for water, gloss at 60°, and the transparencies of those films were measured. The dispersion state of colloidal silica in films was observed with a scanning electron microscope (SEM) and a transmission electron microscope (TEM). From these results, the contact angle for water of the organic-inorganic composite film obtained from the silane hybridized acrylic resin emulsion was lower than that of the organic-inorganic composite film obtained from an acrylic resin emulsion. The contact angles for water in organicinorganic composite films with colloidal silicas were lower than those of the films without the colloidal silicas. The films prepared from silane hybridized acrylic resin emulsion composites with colloidal silicas of less than 100 nm were more hydrophilic. SEM and TEM observations demonstrated that some aggregations of the small colloidal particle silica were densely dispersed on the film surface.

Summary: Solutions containing chitosan of different molecular weights and several acidic monomers were prepared under various aging conditions. Hybrid chitosan/acrylic resin emulsions were prepared from these solutions by emulsion polymerization. The viscosities of the hybrid chitosan/acrylic resin emulsions were influenced significantly by the molecular weight of chitosan, the acidic monomer used, and the aging conditions. DSC and FT‐IR spectroscopy of the hybrid chitosan/acrylic resin films indicated that chitosan was well distributed in the films. The water absorption and formaldehyde adsorption abilities of the acrylic resin films prepared with chitosan were higher than the corresponding films prepared without chitosan, and they increased with increasing molecular weight of the chitosan. The morphology of these films, studied by TEM, revealed that the distribution of chitosan in the hybrid chitosan/acrylic resin emulsion was dependent on the molecular weight of chitosan, the acidic monomer used, and the aging conditions.

An acrylic resin emulsion containing a quaternary ammonium salt (hybrid q‐chitosan/acrylic resin emulsion) was prepared by emulsion polymerization using an acrylic monomer with and without DAAM. DAAM was used to incorporate a functional keto group into the acrylic resin emulsion. Furthermore, a hybrid chitosan/acrylic resin emulsion was prepared for comparison. The elution of q‐chitosan in water from the acrylic resin film with a keto group was less than that from the acrylic resin emulsion without a keto group. In addition, the mechanical properties of the hybrid q‐chitosan/acrylic resin film could be modified by q‐chitosan that was crosslinked between acrylic resin particles. Furthermore, hybrid q‐chitosan/acrylic resin films had adsorption ability for formaldehyde, and the antimicrobial properties of these films were superior to those of the hybrid chitosan/acrylic resin film.magnified image

With the goal of developing a waterborne coating material that prevents staining, organic-inorganic composites prepared from colloidal silica and two types of acrylic resin emulsions were investigated as exterior coatings. Conventional acrylic resin emulsion and organic silane hybridized acrylic resin emulsion prepared by emulsion polymerization were mixed with colloidal silica to form organic-inorganic composite films. The addition of colloidal silica to emulsions yielded films with higher hydrophilicities, as indicated by lower water contact angles for these films in comparison to films without colloidal silica. The water contact angles of organic silane hybridized acrylic resin emulsion/colloidal silica films were lower than those of acrylic resin emulsion/colloidal silica films. Composite films containing colloidal silica particles smaller than 100 nm in diameter showed high hydrophilicities. Observations of the dispersed state of colloidal silica particles in organic-inorganic composite films by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that colloidal silica particles were densely aggregated on the film surface. Outdoor exposure tests of the coating materials prepared from organic silane hybridized acrylic resin and colloidal silica particles with diameters of 7.5 nm showed excellent stain resistance.