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Jute fiber was grafted by acrylonitrile and methylmethacrylate monomers in raw and bleached condition. It was also noted that optimum grafting takes place after about 4 h of grafting. It was also noted that in bleached jute fiber, the grafting percentage is higher at all stages of grafting but the tenacity value at the highest add-on is practically the same as that of raw fiber with much less add-on. The crystalline orientation of the grafted jute fiber was correlated with the fiber tenacity. The moisture regain (%) of the fiber after grafting showed a decreasing trend with an increase in grafting percentage. No structural change of the fiber occurred due to grafting. © 1995 John Wiley & Sons, Inc.

Raw and partially delignified jute fibers were grafted with acrylonitrile and methyl meth-acrylate monomers, using the redox system of initiation with ceric ammonium sulfate. Grafting was also carried out in a mixed monomer system with acrylonitrile and methyl methacrylate monomers in different proportions. The optimum grafting condition depends on the duration of grafting treatment and proportion of grafting monomers. The monomers entered the fiber matrix with high add-on and, at still higher graft add-ons, the ultimate fibers suffered disintegration. The surfaces were increasingly covered with grafted materials and longitudinal cracks developed on the fiber surface with higher add-on. © 1993 John Wiley & Sons, Inc.

Jute stick was treated with white-rot fungus for incubation periods of 6 days (MBA) and 12 days (MBB). The infrared spectra of fungus treated samples (MBA and MBB) and control jute stick (MBC) were analyzed and compared. The bands attributed mainly to hemicellulose show an increase in absorbance intensity ratios (A v /A 2900 ) with increaae of incubation time. Similarly the bands attributed to lignin show an increase in the absorbance intensity ratios with increase of incubation time. Increase in the intensity of 1635 cm -1 band with increases of incubation time was observed.

Jute stick was bleached with sodium chlorite and alkaline hydrogen peroxide solutions. The infrared (IR) spectra of bleached samples and jute stick were analyzed and compared. The bleached samples were characterized by higher absorbance intensity ratios (Av/A2900) of the bands attributed to hemicellulose. Among the bleached samples the chlorite-bleached sample showed higher intensity for the bands mentioned. The bands attributed to lignin are either absent or very weak in the chlorite-bleached jute stick as compared to that of peroxide-bleached jute stick, although some residual lignin was present in the substrate. The 1635 cm−1 band attribute to the vibration of adsorbed water molecules in the noncrystalline regions in cellulose appears as a sharp peak in chlorite-bleached jute stick and as a shoulder in peroxide-bleached jute stick. This can be attributed to the difference in the nature of the two bleaching processes.

Defatted jute stick was treated with sodium hydroxide solution (2% w/v) at ambient temperature (∼ 32∼C) and boiling water bath temperature (95–97°C). Infrared (IR) spectra of defatted jute stick and alkali-treated jute stick were studied. The IR spectra of the alkalitreated jute stick were conspicuous by the absence of the 1730 cm−1 band, as compared to that of jute stick. Another characteristic feature of the alkali treated jute sticks is the absence of the band at 1240 cm−1, which is replaced by the 1265 and 1225 cm−1 bands; other bands in the above samples also recorded significant changes.

The infrared spectra of alkaline jute stick have been discussed and compared to that of untreated and control sample. A higher shift in the OH and lower shift in the CH stretching frequencies were observed in alkaline sample. The presence of a strong band at 1440–1430 cm−1 may be due to the coupling of COO− frequency with CH2 deformation frequency. The CO stretching mode at 1240 cm−1 disappears on alkaline treatment with the formation of new peaks at 1265 and 1225 cm−1. The β−glucosidic band at 895 cm−1 is shifted to 880 cm−1 with doubled intensity in alkaline jute stick.

Les resultats du greffage de fibres brutes et blanchies montrent que l'acrylonitrile est greffe sur la lignine et la cellulose