Immediate Onset of the Trommsdorff Effect

In the bulk polymerization of methyl methacrylate (MMA), the Trommsdorff effect sets in after an unperturbed period of about 15-20 % conversion. This enables a separation to be made between unperturbed and autoaccelerated kinetics. Benson and North, O Driscoll, Ito and others have attempted to describe the kinetics of autoacceleration or gelation by introducing a chain-length-dependent value of the termination rate constant 

Tulig and Tirrell extended the gelation model by including diffusion by repta-tion 

The polymerization of acrylates is much more difficult to analyse since gelation sets in near zero conversion probably due to branching and crosslinking 

With the chain crosslinking polymerization of undiluted tetrafunctional monomers gelation starts almost immediately (Fig. 1) and at present such systems cannot be described kinetically. Since the cause of the autoacceleration is a physical one (sup- 

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