Resumo

RINTOUL, I.  e  WANDREY, C.. Limit of applicability of the monomer-enhanced mechanism for radical generation in persulfate initiated mechanism for radical generationin persulfate initiated polymerization of acrylamide. Lat. Am. appl. res. [online]. 2010, vol.40, n.4, pp.365-372. ISSN 0327-0793.

The limit of applicability of the monomer-enhanced mechanism as dominant mechanism ruling the initiation process of the polymerization of acrylamide (AM) initiated with potassium persulfate (K₂S₂O₈) has been determined. The kinetics and mechanisms for radical generation were studied in solution at very low monomer and initiator concentrations. The transition of the initiation mechanism from dominant monomer-enhanced dissociation to dominant thermal decomposition of persulfate was observed. Both mechanisms contribute equally to radical generation at [AM] / [K₂S₂O₈] ≈ 4.5. Thermal decomposition dominates at lower [AM] or higher [K₂S₂O₈] and opposite variations promote the monomer-enhanced dissociation. This work also includes quantification of the rate coefficients, efficiencies and activation energies of the mentioned mechanisms, and the kinetics of AM polymerization when photochemically initiated with phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide.

Palavras-chave : Kinetics; Mechanism; Initiation; Acrylamide; Persulfate.

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