Abstract: A method for forming a polymer-filler composite having advantageous bound filler content, the method comprising (a) providing a guayule cement; (b) introducing particulate filler to the guayule cement to form a solution masterbatch; and (c) desolventizing the solution masterbatch to form a polymer-filler composite.

Abstract: Methods for producing an uncured masterbatch material from a solution masterbatch that includes an uncured polymer, for example a polydiene such as present in a guayule cement, a diluting liquid and a particulate filler. The solution masterbatch is subjected to resonant acoustic mixing which provides excellent dispersion of the solution components and leads to a masterbatch material having desirable properties. After resonant acoustic mixing, the solution masterbatch can be dried and further processed with other components and a curative to prepare a vulcanized composition.