CLOSED-LOOP VISCOSITY CONTROL OF REACTIVE EXTRUSION WITH AN IN-LINE RHEOMETER

A novel in-line melt rheometer (ILR) measured viscosity to control ion omer neutralization during reactive extrusion. The ILR has the advanta ges of an in-line location to minimize measurement delay and a ''parti al Couette'' flow geometry, which affords independent control of the s hear rate. The reactive extrusion process for ethylene methacrylic aci d (EMAA) ionomer neutralization was modeled as a first order plus dead time process. A comparison of the process responses to experimentally determined residence time distributions for the extruder showed that there was an appreciable inherent delay despite the advantage of the r heometer's in-line location. Proportional-integral and minimum varianc e control algorithms were implemented. The quality of control was gene rally good, but demonstrated the nonlinearity of the neutralization pr ocess, suggesting that adaptive control techniques could improve contr ol performance.