Methods and systems for solution polymerization. The method can include forming a first mixture stream consisting essentially of at least one catalyst and a process solvent, and forming a second mixture stream consisting essentially of at least one activator and the process solvent. The first mixture stream and the second mixture stream can be fed separately to at least one reaction zone comprising one or more monomers dissolved in the process solvent where the at least one monomers can be polymerized within the at least one reaction zone in the presence of the catalyst, activator and process solvent to produce a polymer product.