Abstract: Synthetic elastomers are typically made commercially by employing emulsion polymerization or solution polymerization techniques. In such solution polymerization techniques, it is desirable to operate at the highest solids content which is practical. As a general rule, it is not practical to prepare such rubbers by solution polymerization at solids contents of higher than about 20 percent. However, the subject invention reveals a technique for preparing such rubbers by high solids solution polymerization at extremely high solids contents. This technique offers substantial advantages associated with eliminating large quantities of organic solvents.