Abstract
When 6-nylon fibers were treated with ceric salt in aqueous acetic acid, the successive first order reactions (A_??_B_??_C) occurred where A is CeIV in the solution, B is CeIV adsorbed on nylon and C is CeIII produced by reduction of adsorbed CeIV. The decrease in the concentration of CeIV in solution and the amount of CeIV adsorbed were determined by titration from which the amount of CeIV reduced was calculated. The rate constants of adsorption and reduction of CeIV (k1 and k2) were obtained from the initial rates of the decrease of CeIV in solution and the maximum value of CeIV adsorbed. When the treatment was done in the presence of methyl methacrylate (MMA), the rates of decrease of CeIV in solution, adsorption and reduction decreased and the maximum value of CeIV adsorbed increased. It was considered that graft copolymerization took place when monomers were present in the reaction medium, on the other hand, when monomers were absent the nylon radicals formed were further oxidized. Application of Langmuir's isotherm equation to the system investigated showed that the adsorption of CeIV per repeating unit of nylon was two.
Graft copolymerization of vinyl monomers (mainly MMA) onto nylon fibers pretreated with CeIV followed by centrifugal separation was carried out in aqueous acetic acid. Effects of various reaction variables on the graft-on, molecular weight of the graft polymer and the number of grafting were studied. Methyl acrylate graft-copolymerized the most among the monomers used.
