| Abstract: | Graft copolymerization of N-methylolacrylamide onto flax/polyester blend fabric using ferrous cellulose thiocarbonate/H2O2 redox system was investigated under different conditions including hydrogen peroxide concentration (1?60 mmol/l), ferrous ammonium sulphate concentration (1?50 mmol/l), N-methylolacrylamide concentration (5?200%, based on weight of sample), polymerization time (10?90 min), temperature (20?50°C), and pH of the medium (1.1?11). The nitrogen content and/or the methylol content were used for calculation of graft yields. Results obtained indicated that graft yields, derived from nitrogen analysis, are higher the greater the H2O2 concentration increases till 40 mmol/l, then level off. On the other hand, graft yields derived from methylol content exhibit maximum value at 10 mmol/l H2O2. The results indicate also that grafting was highly favoured when it was carried out using 1 mmol/l ferrous ammonium sulphate and pH 4.4 at 30°C for 60 min. The apparent activation energy of the copolymerization reaction amounts to 9.74 kJ/mol. Furthermore, the graft yield increases by increasing N-methylolacrylamide concentration within the range studied. The work was further extended to include a comparison between the polymerization efficiencies of the ferrous cellulose thiocarbonate/H2O2 redox system and the ferrous/H2O2 redox system in inducing grafting of N-methylolacrylamide onto flax/polyester blend fabric. For this reason, the two systems were studied with respect to graft yield, homopolymer proportion, total conversion, graft efficiency, and homopolymer efficiency. |
