Kinetics and modeling of 2-(diethylamino)ethyl methacrylate depropagation in bulk and solution free radical polymerization

The effect of depropagation was investigated in batch bulk and solution polymerizations of 2-(Diethyl Amino)Ethyl Methacrylate (DEAEMA) at 70, 95 and 120 °C, which is valuable system on the development of pH and thermo-sensitivity materials. A kinetic analysis shows that the apparent rate coefficient ( k app = k p / k t 0.5 ) slightly decreases with temperature and the concentration. The standard-state enthalpy ( ∆ H p ° ) and entropy ( ∆ S p ° ) of polymerization are estimated in values of (−45.84 ± 0.50) kJ mol −1 and (−123.32 ± 1.33) J mol −1 K −1 , respectively, for bulk DEAEMA polymerization. This leads to a low ceiling temperature for DEAEMA of T c = 98.5 °C calculated at M ° = 1 mol L −1 , which is lower than other methacrylates. A kinetic model, based on the direct integration of the population balance equations, provides a good fit with experimental data of monomer conversion, average molar masses and molar mass distribution, for bulk and solution polymerizations at moderate and high temperatures. Polymerizations in either bulk or solution produce low molar mass chains attributable to a combined effect of depropagation and chain transfer to monomer. According to the proposed rate coefficients and the DEAEMA polymerization mechanism, the full kinetic picture is accurately illustrated.