Temperature can only increase until

Temperature can only increase until the catalyst active sites (dispersed into the polymer phase) can still be reached by the monomers diffusing onto their surfaces; a temperature increase above 100°C causes a fast deactivation of the catalyst system through the sintering, and ultimately the melting, of the polymer particles. Active sites will no longer be available to the monomers, and the reaction will cease by itself. Therefore, only temperature values well below the design value can be reached in the equipment.