ABSTRACT
For the description of reactive extrusion it is important to know the kinetics in all stadia of the reactions, from diluted solutions to concentrated melts. Unfortunately, most kinetic experiments reported in literature are performed only in strongly diluted systems, whereas in extrusion polymerization the polymer concentration changes in time between 0 and approximately 100%. Due to the reduced termination velocity the amount of active polymer radicals increases, resulting in an abrupt increase of the propagation velocity and of the momentary degree of polymerization. Most studies on the kinetics of polymerization reactions have been limited to low degrees of conversion and low reaction temperatures. In step-growth polymerizations the reacting mass consists, after an initiation period, of a polymeric melt that on reacting increases in molecular weight by combination. If reactive extrusion is used for step-growth polymerizations, only bifunctional monomers should be used.
