A novel photo-grafting of acrylamide onto carboxymethyl starch. 1. Utilization of CMS-g-PAAm in easy care finishing of cotton fabrics

• UV irradiation/4-(trimethyl ammoniummethyl) benzophenone chloride photoinitiator as a novel photografting system.
• Synthesis of carboxymethyl starch −g- polyacrylamide with grafting yield up to 98.9%.
• Utilization of the methylolated product of carboxymethyl starch −g- polyacrylamide in easy care finishing of cotton fabrics.
• Significant increase in CRA after finishing of cotton fabrics with methylolated product.
• Insignificant decrease of the CRA and significant decrease in RF of finished fabric after five washing cycles.

The photosensitized grafting of vinyl monomers onto a range of polymeric substrates has been the subject of particular interest in the recent past. Carboxymethyl starch (CMS)-poly acrylamide (PAAm) graft copolymer (CMS-g-PAAm) with high graft yield was successfully prepared by grafting of acrylamide onto CMS using UV irradiation in the presence of the water soluble 4-(trimethyl ammoniummethyl) benzophenone chloride photoinitiator. CMS-g-PAAm with nitrogen content of 8.3% and grafting efficiency up to 98.9% was obtained using 100% AAm, a material: liquor ratio of 1:14 and 1% photinitiator at 30 °C for 1 h of UV irradiation. The synthesis of CMS-g-PAAm was confirmed by FTIR and Nitrogen content (%). Surface morphology of CMS and surface morphological changes of CMS after grafting with AAm were studied using SEM. Thermal properties of both CMS and CMS-g-PAAm were studied using TGA and DSC. To impart easy care finishing to cotton fabrics, aqueous formulations of: CMS-g-PAAm, dimethylol dihydroxy ethylene urea (DMDHEU), CMS-g-PAAm-DMDHEU mixture or methylolated CMS-g-PAAm were used. Cotton fabrics were padded in these formulations, squeezed to a wet pick up 100%, dried at 100 °C for 5 min, cured at 150 °C for 5 min, washed at 50 °C for 10 min and air-dried. CRA (crease recovery angle) of untreated fabrics and fabrics finished with a mixture of 2% CMS-g-PAAm and 10% DMDHEU or methylolated CMS-g-PAAm (10% formaldehyde) were: 136°, 190°, 288° respectively. Increasing the number of washing cycles up to five cycles results in an insignificant decrease in the CRA and a significant decrease in RF (releasable formaldehyde) of finished fabric samples. The morphologies of the finished and unfinished cotton fabrics were performed by SEM.