Tomasz Graczyk

Grafting of methyl acrylate onto cellulose by ceric ion

Abstract Methyl acrylate was grafted onto dissolving pulp by ceric ion in aqueous sulfuric acid under oxygen-free argon. At a low Ce(IV) concentration (up to 1 mmol/L), the rate of polymerization (Rp ) is proportional to [Ce]0.5 [MA]1 [cellulose]1. At higher concentrations of cericion (1–20 mmol/L), Rp is proportional to [Ce]0 [M] 1.5 [cellulose]1. The mechanism of grafting is consistent with a kinetic scheme involving initiation by primary radicals and termination by growing polymer radicals. Above 20 mmol/L of ceric salt, the data are consistent with the linear termination mode.

Graft Copolymerization of Methyl Acrylate by Ceric Ion in the Presence of a Controlled Amount of Oxygen

Abstract Methyl acrylate (MA) was grafted onto dissolving pulp by eerie sulfate in the presence of a controlled amount of oxygen. the magnitude and location of the maximum on the conversion vs the agitation speed curve are dependent on reaction conditions. the concentration of eerie sulfate and the reaction time are the most important determinants. the type of stirrer has only limited influence. the Ce(IV) consumption rises with increasing stirring speed due to higher diffusion of oxygen to active centers and is higher than for the oxidation of cellulose. the difference in Ce(IV) consumption for grafting and oxidation is not directly related to the amount of homopolymer because the grafting efficiency is independent of agitator speed. the rate of grafting is proportional to the amount of monomer to the second power, as a result of reaction of primary radicals with oxygen. Adding the MA later than the eerie sulfate causes a considerable increase in the induction period but no increase in the conversion. Hy...

Polymerization of Vinyl Monomers in Organic Solutions of Cellulose

Abstract Methyl methacrylate and other monomers were polymerized in systems involving cellulose completely or partially dissolved in complex solvents. Both the system [dimethylsulfoxide-sulfur dioxide] and the system [dimethylformamide-copper nitrate-cumene hydroperoxide] were found to be effective in initiating polymerization. In the presence of air, cellulose seemed to counteract the inhibiting effect of oxygen. All the reactions resulted in the formation of homopolymer only, and no graft co-polymers of cellulose were detected in the products.

Grafting of Cellulose with Water-Soluble Monomers by the Xanthate Process

Abstract Cellulose was grafted with several water-soluble monomers including 2-dimethylaminoethyl methacrylate, 3-dimethylaminopropyl methacrylamide, and 2-acrylamido-2-methylpropyl sulfonic acid. Cellulose xanthate-Fe2-H2O3 redox system was used to initiate the polymerizations. The formation of graft copolymer was investigated as a function of substrate pretreatment, initial pH, and reaction temperature. Although stable graft copolymer was formed in all cases, the grafting efficiency was quite low, ranging from 10 to 30%. The best results were obtained with binary monomer mixtures composed of an acid and a base.