Investigation of the adiabatic free radical copolymerization of MMA/EGDMA

An objective of this investigation is to develop a polymerization model for the copolymerization of methyl methacrylate (MMA)/ethylglycol dimethacrylate (EGDMA), using a novel adiabatic reactor for the experimentation. The model should, in principle, predict adiabatic temperature and pressure rise with adequate accuracy for safety calculations. Experimental data show that the polymerization rate increases significantly with increase of EGDMA concentration, as 15.0 min for the pure MMA polymerization reaching its maximum reaction rate while only 2.0 min for 20 wt% EGDMA. The polymerization rate falls dramatically after the temperature reaches 175°C. Combined with the fact that the final products always have 20% unreacted monomer and oligomers, it may be suggested that (a) significant depropagation occurs at these high temperatures; (b) significant decrease in initiator efficiency; and/or (c) strongly diffused-controlled propagation. There exists some critical concentration of EGDMA for formation of crosslinked polymer.