GRAFT-COPOLYMERIZATION OF ACRYLIC-ACID ONTO CAESARWEED FIBERS BY CERRIC ION TOLUENE REDOX PAIR

The graft copolymerization of acrylic acid onto caesarweed fibers in aqueous media by cerric ion-toluene redox pair has been investigated. The percentage graft. increased and then decreased with cerric ion concentration ranging from 8.3 to 100.0 X 10(-3)M with a peak value of 17%. The effects of toluene, substituted toluenes, acids, and acrylic acid were examined. The percentage graft increased and then decreased with toluene concentration with an optimum value of 53% at 18.0 X 10(-4)M toluene. Under identical reaction conditions, the percentage graft after 30 min for the graft polymerization initiated by substituted toluenes are in the order of p-toluene sulfonic acid > toluene > p-Xylene similar or equal to o-toluidine. Low concentrations of acetic acid were favorable to the graft polymerization. The percentage graft increased linearly with acrylic acid concentration reaching a value of 53% at 1.39M acrylic acid. The presence of neutral salts had nominal effects on the percentage graft. The effect of temperature was investigated between 20 and 60 degrees C. The percentage graft increased with temperature up to 40 degrees C but showed a negative temperature dependence beyond 40 degrees C. The calculated activation energy was 6.2 kcal mol(-1). Characterization of the physical properties of the grafted fibers was also conducted. (C) 1994 John Wiley and Sons, Inc.