Structural and Chemical Modification of Polydiene Latexes by Gel Derived Silica

Latex-silicate compositions and unsupported films (green and vulcanized) were prepared by mixing natural Qualitex and synthetic butadiene-styrene (SKSS) latexes with an aqueous solution of sodium silicate modified with a zinc tetrammine complex. The mechanism and efficiency of the inorganic modification of latex structures were investigated by UV-vis and IR spectrophotometry, rotational viscometry of liquid and gelled mixtures as well as by tensile testing of the prepared films. Measurements showed an increase of elastic modulus and tensile strength with silica concentration for all composite films except for the green SKSS-based ones. The improvement of mechanical properties can be related to the formation of interpenetrating organic and silicate networks linked by Zn atoms that can also participate in the vulcanization process.