Die Makromolekulare Chemie · 1989 · 15 citations · 10 references
Natural SciencesChemistryMaterials SciencePolymer ChemistryPolymer EngineeringPolymer MaterialsAcrylic Resin MaterialsPhotochemistryPolymer Physical ChemistryPolymerization ChemistryPolymerization KineticsPolymerization ProcessesConcentrationLight IntensityPhotoinitiator ChemistryPhotopolymerizationPhotopolymerization KineticsPolymerization Rate ConstantsPolymerization Rate ControlPolymerization Reactions
Abstract The photoredox process occurring between HCrO 4 − and acrylamide (AAm) leads to the formation of chromium(III) and polyacrylamide. The influence of pH, monomer concentration, absorbed light intensity I a and chromium(VI) concentration on the polymerization rate R p are reported. Two different domains are detected as a function of chromium(VI) concentration: At low concentration, where R p increases with chromium concentration, a process of termination by mutual annihilation of the macroradicals accounts for the experimental dependence R p ∝ [AAm] 3/2 · I a . At higher concentration, R p decreases when the chromium concentration increases; a process of oxidative termination of the radicals by chromium(VI) is involved corresponding to a dependence R p ∝ [AAm] 2 . I a . The evolution of the polymer molecular weight as a function of the different parameters controlling the polymerization is described.
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