Modification of cotton by acrylic acid (AA) in the presence of NaH2PO4 andK2S2O8 as catalysts under thermal treatment

Cotton fabric was modified using acrylic acid (AA) as the finishing agent i n the presence of K2S2O8 and NaH2PO4 catalysts separately or in selected co mbinations, employing a pad-dry-cure technique. Treatment with 8% AA at 30 degrees C and at pH 7 produced optimum effects: a batching time of 30-45 mi n at 30 degrees C followed by drying of the batched fabric at 95 degrees C for 5 min and curing of the dried fabric at 140 degrees C for 5 min produce d most balanced improvements in the textile related properties. NaH2PO4 cat alyst allowed esterification of AA with the cellulosic constituent of cotto n, and K2S2O8 catalyst allowed radical polymerization of free-AA or cotton bound AA moieties, ultimately leading to some degree of crosslinking of the chain polymers of cotton. Examination of the surface morphology of untreat ed and treated cotton fabrics by scanning electron microscopy revealed a go od degree of masking of the convolutions of the cellulosic fibres and surfa ce crack by a cohesive film of poly(acrylic acid) or its salt, particularly when K2S2O8 was used either alone or in combination with NaH2PO4 as cataly st. (C) 2000 Elsevier Science Ltd. All rights reserved.