Effect of structural changes of cotton by acid hydrolysis and crosslinking on soiling and soil release



The effect of acid hydrolysis (0.5N HC1 at 60°C for 5–90 min) on the soiling and soil release properties of cotton fabric before and after crosslinking was investigated. The effect of acid hydrolysis of crosslinked cotton under similar condition on the same properties was also undertaken. Crosslinking with and without nonionic softener was carried out using dimethylol dihydroxyethlene urea and magnesium chloide hexahydrate as a catalyst. Aqueous and nonaqueous oily dispersions of carbon black were used for soiling. Results of these studies disclosed that acid hydrolysis prior to crosslinking imparted aqueous and oily soil resistance to the cotton, particularly during the very initial stages of hydrolysis treatment. Crosslinking of cotton and acid-treated cottons in the absence of softener accentuated soil resistance. The opposite holds true for crosslinking in the presence of softener. Short acid treatment of cotton before and after corsslinking decreased the ability of cotton to release the aqueous and oily soils. On the other hand, acid hydrolysis of crosslinked cotton improved aqueous and nonaqueous soil-resistance provided that the duration did not exceed 30 min. Hydrolysis accentuated also the ease of oily soil removal, but aqueous soil release was adversely affected. The results were interpreted in terms of changes in the physical and chemical structures of cotton and crosslinked cottons brought about by acid hydrolysis.