Zwitterion Silane-Modified Polymer Latexes

Silicone modification of alkyds, epoxies, acrylics and other coating resins are well-known for imparting improved gloss retention and weather resistance [1]. Copolymers of structure (Siloxane) = SiOCH2-(Resin) are prepared in organic solvents with relatively large proportions of silicone, since performance is approximately proportional to the silicone content. [Pg.119]

Although aqueous suspension copolymerization of vinyl monomers and reactive trialkoxysilanes generally leads to cross-linked polymers [2], it has been observed that silanol-modified emulsified copolymers are quite stable and do not cross-link until the polymer films dry. Silanol groups apparently are stabilized by orientation at the polymer-water interface and act as hydrophilic emulsion stabilizers comparable to carboxyl groups [3]. After the latex is deposited as a film, the silanol groups condense to form siloxanemodified water-resistant coatings. [Pg.119]

Silane-modified emulsion copolymers may be prepared by direct emulsion copolymerization of suitable silanes with other monomers, but it would be much more convenient to modify existing emulsion polymers by simple additions of silanes. [Pg.119]

Additions of alkoxysilanes to aqueous polymer emulsions give a complex physical-chemical system that may undergo marked changes in the latex and in deposited films with aging, but allows separate deposition of silane and polymer from a single solution. [Pg.119]

The nature of aqueous solutions of silane coupling agents has been studied rather extensively [4]. Neutral alkoxysilanes hydrolyze rapidly at pH 4 to alkylsilane triols, and then condense slowly to oligomeric organosiloxanols. [Pg.119]

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