The thermal decomposition rate constant of AIBN (𝓀d) in N,N‐dimethylformamide (DMF)/methyl methacrylate (MM) mixtures of various compositions at 60°C is studied. The 𝓀d value is 6.45 × 10−4min−1 for pure DMF and 7.20 × 10−1 min−1 for pure methyl methacrylate. The 𝓀d values of DMF/MM mixtures were found to be dependent on the mixture composition. This dependence is not a linear function of the monomer mole fraction, but has a minimum at ca. 20 30 mol% of MM. The relationship between the AIBN decomposition rate constant and the monomer mole fraction was interpreted on the basis of solvation of the initiator molecules. © 1995 John Wiley & Sons, Inc.

The thermal decomposition rate constant of AIBN (kd) in N, N‐dimethylformamide (DMF)/acrylonitrile (AN) mixtures of various compositions at 60°C is studied. The kd value is (6.45 ± 0.3) × 10−4 min−1 for pure DMF and (7.20 ± 0.3) × 10−4 min−1 for pure acrylonitrile. The kd values of DMF/AN mixtures were found to be dependent on the mixture composition. This dependence is not a linear function of the monomer mole fraction (xM), but has a minimum at ca. 70 mol % of AN. The relationship kd = f(xM) has been interpreted on the basis of the hypothesis of initiator solvation by monomer AN and solvent DMF. © 1996 John Wiley & Sons, Inc.

The solvation effect in the thermal decomposition of a radical initiator (AIBN) in monomer–solvent mixtures is discussed. Equations were derived which comprise the initiator decomposition constant as a function of the monomer mole fraction for chosen types of solvation. In addition, equations were deduced presenting the concentrations and partial relative decomposition rates for the solvated initiator species as a function of the monomer mole fraction. The equations obtained were compared to the experimental literature data and possible dependences of decomposition constants on monomer concentration were simulated for various solvated species. The simulated relationships were found to be straight lines, curves of saturated type (possessing a plateau), S‐shaped curves, and maximum or minimum curves. © 1995 John Wiley & Sons, Inc.