NOPR Collection:

Physico-chemical nature of ramie at different stages of growth

1995-09-01T00:00:00Z

Title: Physico-chemical nature of ramie at different stages of growth Authors: Kundu, P K; Sarmah, R; Sarkar, C R Abstract: The physico-chemical nature of ramie at different stages of crop growth has been studied by infrared spectroscopy and also by biochemical estimation of gums and pectins. From IR study, the pectin has been found to be maximum for 40 days old ramie whereas the gums (mainly hemicellulose) have been found to be maximum for 70 days old ramie. The biochemical estimation of gum and pectin contents supports the results of IR study. The ramie plant can be harvested for efficient degumming after 70 days due to high formation of cellulose and less formation of pectin. Page(s): 165-167

Kinetics of dyeing of rotor- and ring-spun cotton yarns

1995-09-01T00:00:00Z

Title: Kinetics of dyeing of rotor- and ring-spun cotton yarns Authors: Iyer, V; Iyer, J K; Shenai, V A Abstract: Ring-spun and rotor-spun cotton yarns were dyed with one commercial reactive dye (Amective Golden Yellow IRX) and two direct dyes (Chrysophenine G and Incomine Sky Blue 6B) at three different temperatures till the equilibrium was attained in each case. The dye bath exhaustion and equilibrium exhaustion values were used to calculate the apparent diffusion coefficients using a simple equation. Tile apparent diffusion coefficients determined at different temperatures were further used to derive the apparent activation energy of the dyeing process. The activation energies for both ring-spun and rotor-spun yarns have been found to be comparable. The apparent activation energies of direct dyes are much higher than those of reactive dyes. Page(s): 161-164

Brightening of grey jute-Mechanism and application

1995-09-01T00:00:00Z

Title: Brightening of grey jute-Mechanism and application Authors: Chakrabarti, S K; Ghosh, B S; Adhikari, D; Kundu, A B Abstract: Ferric iron in combination with phenolic groups of tannin and phenolic acid lignin imparts grey colour in jute. Treatment with EDTA removed almost all the Fe(III), improving the brightness significantly but caused over-yellowing of fibres. Evidences presented suggest that the removal of metal ions bound with phenolic groups generated free phenolic-OH which on aerial oxidation caused the over-yellowing. Reducing action of dithionite minimized such oxidation and prevented over-yellowing. Besides, dithionite reduced Fe(lII) to soluble Fe(II), there by enhanced the brightening process. Thus, the combined action of EDTA and dithionite induced a high brightness and restored the natural yellow colour of jute. Brightening of jute under submerged condition proved uneconomical due to the expenses of post-treatment drying. Treatment at a low level of moisture eliminated the above. This Was done by spraying brightening chemicals on fibres before piling. The prolonged piling time and inherent acidity of fibres favoured the brightening reactions. The resultant fibres were brightened appreciably and the yarn spun thereof was found to be superior in quality compared to control. Page(s): 156-160

Dyeing of silk with Procion HE dyes

1995-09-01T00:00:00Z

Title: Dyeing of silk with Procion HE dyes Authors: Gulrajani, M L; Jain, Ashish; Agarwal, Deepali Abstract: The effect of various dyeing parameters on exhaustion and fixation of bifunctional monochlorotriazine dyes (Procion HE dyes) on silk has been studied. Factorial design has been used to obtain the optimum conditions of dyeing. Maximum exhaustion has been obtained with 110 g/L sodium chloride and 3 g/L sodium carbonate. Temperature in the range 60-80°C has no influence on exhaustion. Improvement in mechanical properties of dyed silk suggests the formation of crosslinks in the fibre by these dyes. Page(s): 150-155