| abstract |
It is sometimes advantageous to disperse crystalline polymers throughout rubbery elastomers. For instance, the cold flow characteristics and green strength of polydiene rubbers can be improved by dispersing syndiotactic-1,2-polybutadiene therein. This invention discloses a process for preparing a highly dispersed blend of a crystalline polymer in a rubbery elastomer which comprises (1) polymerizing at least one diene monomer in an organic solvent under solution polymerization conditions to form a polymer cement of the rubbery elastomer in the organic solvent, (2) polymerizing additional monomers in the polymer cement into the crystalline polymer to form a rubbery cement having the crystalline polymer dispersed therein, and (3) recovering the highly dispersed blend of the crystalline polymer in the rubbery elastomer from the organic solvent in the rubber cement. |