RHEOKINETIC STUDIES FOR THE REACTION INJECTION-MOLDING OF POLYDICYCLOPENTADIENE

Dicyclopentadiene (DCPD) based liquid engineered resins are emerging a mong the newest commercial reaction injection molding (RIM) systems. S ince the filling stage is coupled with chemical reaction, an understan ding of the chemorheological changes is critical for establishing mold ability criteria. An adiabatic reactive viscometry technique which inv olves the simultaneous measurement of viscosity and temperature change s was used to investigate the chemorheological changes during the adia batic copolymerization of a DCPD based RIM system. The influence of im pingement mixing conditions and initial material temperature on the re action kinetics, rheology, as well as the resulting final physical pro perties of the system were investigated. The ''apparent gel time'' und er adiabatic conditions is estimated from the intersection of the tang ents to the initial and final portions of the viscosity curve. An auto catalytic kinetic model with an Arrhenius rate constant was used to mo del the reaction kinetics.