Polymerization of methyl methacrylate in solution

Abstract

The polymerization of methyl methacrylate in solvents of different nature and viscosity, has been studied at 60°C using azobisisobutyronitrile as initiator. K, and Ri have been determined by means of rate and molecular weight and assuming that Kt M l/qrnix. The propagation coefficient and the rate of initiation, both seems to be affected by the nature of the solvents. ZUSAMMENFASSUNG: Es wurde die Polymerisation von Methylmethacrylat in Losungsmitteln verschiedenerArt und Viskositat bei 60 "C unter Verwendung von Azoisobuttersauredinitril als Initiator untersucht. K, und Ri wurden durch Reaktionsgeschwindigkeit und Molekulargewicht unter der Voraussetzung, daR Kt M l /~~i~~h . ist, bestimmt. Der Wachstumskoeffizient und die Initiierungsgeschwindigkeit scheinen von der Art des Losungsmittels abhangig zu sein.

Bimolecular Free-Radical Termination at Low Conversion

“…40 and 61-85). Several years earlier, Benson and North (40) had reported similar results for MMA, and this dependence was later abundantly confirmed by others (66)(67)(68)(69)(70)(71)(72)(73)(74)86). The viscosity can either be varied using different solvents with inherently different viscosities, or alternatively, various amounts of polymer can be dissolved as a viscosity modifier.…”

“…This was actually already the case in some of the MMA studies in different solvents, as mentioned above (40,(66)(67)(68)(69)(70)(71)(72)(73)77), as not all these solvents dissolve pMMA (polymethylmethacrylate) equally well (95). This complexity arises from the fact that, if one solvent is replaced by another (or, alternatively, as soon as some polymer has been formed), the thermodynamic properties of the solution change simultaneously.…”

Effect of solvent on the termination rate constant in initial stages of free radical polymerization

“…Here K and a are the constants in the Mark-Houwink equation: [v] = KMa (9) M is the polymer (or radical) molecular weight and Mo is the formula weight of the monomer. Equation (8) simplifies to Qo = pF" (10) where p and V are defined by comparison with eq. (8).…”

Solvent effects on free‐radical polymerization, 3. Solvent effect on polymerization rate of methyl methacrylate and N‐vinyl‐2‐pyrrolidone

“…revealed that both rate constants can be affected by solvents. The termination rate constant depends inversely on viscosity of the reaction medium 18-22,28), but factors influencing the propagation rate constant are not fully clarified3, [19][20][21][22][23][24][25][26][27]. Authors propose several hypotheses like complexing of growing radicals by solvent^^^-^^), "hot radical" t h e~r y *~-*~) or specific (preferential) solvatation of the growing radicals by solvent, i. e., non-I : 1 complex formation 34-37).…”