Abstract: Methods are disclosed for a novel and useful single pass extrusion process for the reactive extrusion and compounding of polymers. Traditional extruders utilized in reactive processes are of length to diameter ratios ranging from 30 to 1 to as high as 56 to 1. The process disclosed uses a series of sequential, very closely-coupled, independently driven screw extruders having a total effective length to diameter ratio much greater than 70 to 1 and as high as 132 to 1 or greater, and providing greatly extended reaction times, separate and multiple introductions of reactive and non-reactive agents and mechanical connections allowing for convenient screw changes and differential thermal expansion. The assembly is employed to economically produce grafted polyolefins, produce ionomers without employing the use of strong caustic agents, remove large volumes of unwanted polymer processing solvents and produce other reacted polymer species in one continuous pass.