Modification of polyester fabric via radiation grafting with methacrylic acid

Polyester fabric has been modified by radiation graft copolymerizaion with methacrylic acid (MAA) to improve its hydrophilic, dyeing and thermal properties. It is observed that the efficiency of grafting significantly depends on swelling agent, solvent, monomer concentration and irradiation time. The initial stage of grafting follows first order kinetics at irradiation time t < 41.5 min and the second stage follows 1.7 order kinetics at 41.5-170 min. Overall reaction rate constants of 1.9x10(-5) and 2.87x10(-4) s(-1) have been calculated for the samples grafted below and above 41.5 min respectively. The moisture content is found to increase linearly with the increase in graft yield up to 28% while the water uptake is linearly dependent on the logarithm of graft yield. Extremely high colour strength values are obtained when grafted PET samples are dyed in alkaline aqueous solutions at pH 11.5. A linear dependence is observed between the colour strength per graft yield and the logarithm of the pH of Rhodamine B Red and Astrazonrot Violet dye solutions. The dyeability of the fabric towards both the dyes increases suddenly as the graft yield increases to 2.5% followed by a transition up to 7% with a tendency to level off at degree of grafting higher than 10%. Thermal stability of irradiated, grafted and dyed samples has also been investigated by thermal gravimetric analysis to observe different degrees of fabric degradation as a result of irradiation, grafting and dyeing.