Grafting acrylonitrile on kenaf fibers using ceric ion–p-xylene redox pair

✍ Scribed by I. C. Eromosele; A. Agbo

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 140 KB
• Volume: 73
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19990829)73:9<1751::aid-app16>3.0.co;2-9

✦ Synopsis

Polyacrylonitrile was grafted onto kenaf fibers in aqueous media by ceric ion-p-xylene redox system. The graft yield dependence on p-xylene concentration in the range 1.8 -45.0 ϫ 10 Ϫ4 M showed a minimum accompanied by an enhanced yield. This suggested the existence of two kinetically distinct grafting reactions associated with two precursor-initiating species, a p-xylyl radical and a diradical. The frequency of graft F g and the average molecular weight of grafted polymer M v were inversely related at varying concentrations of p-xylene with values for M v of up to 5.18 ϫ 10 4 . The effect of ceric ion concentration on M v showed that the ion is nonterminating at low concentrations in the range 8.3-33.3 ϫ 10 Ϫ3 M. The graft yield showed positive temperature dependence in the region of 30 -40°C and a negative one at higher temperatures, resulting in a decrease in the initial rate of graft at 70°C by a factor of 8 compared to its value at 40°C.