Abstract: A method for producing a functionalized polymer, the method comprising the steps of: (i) preparing a bulk polymerization system including a reactive polymer by introducing a lanthanide-based catalyst and a conjugated diene monomer; (ii) adding a heterocyclic nitrile compound the polymerization system including the reactive polymer to prepare polymerization system including a functionalized polymer; and (iii) adding a protic compound to the polymerization system including a functionalized polymer where the ratio of water or protic hydrogen atoms in the protic compound to the lanthanide atoms in the lanthanide-based catalyst is at least 1500 to 1.

Abstract: A method for producing polyisoprene, the method comprising the steps of preparing a preformed lanthanide-based catalyst in the presence of 1,3-butadiene and forming a polymerization mixture by introducing the preformed catalyst to isoprene, where the polymerization mixture includes less than 20% by weight of organic solvent based upon the total weight of the polymerization mixture.