An eco-friendly approach to low-temperature and near-neutral bleaching of cotton knitted fabrics using glycerol triacetate as an activator

摘要

Near-neutral bleaching of cotton fabrics at low temperature is of great importance for saving energy and ecological friendliness in textile industry. In this work, glycerol triacetate (GT) was investigated as an activator of hydrogen peroxide (H2O2) for low temperature bleaching of cotton knitted fabrics, and satisfactory whiteness was obtained. The bleaching properties of H2O2/GT system for cotton was assessed by the CIE whiteness index (WI), H2O2 decomposition rate, concentration of generated peracetic acid and bursting strength. Possible factors affecting the properties of cotton bleached by H2O2/GT bleaching system were discussed in detail. At 60 degrees C, adding only 10 mmol/L GT to the hydrogen peroxide solution (60 mmol/L) to bleach cotton knitted fabrics for 60 min, the WI was significantly increased from 52.09 to 68.92. By using benzenepentacarboxylic acid as a fluorescent probe for hydroxyl radical (HO center dot) detection, it was found that GT could clearly promote HO center dot generation and its concentration closely related to the WI of cotton fabric. Furthermore, the bleaching mechanism of H2O2/GT system was proposed by exploring the relationship between WI and HO center dot concentration. GT as a bleach activator has more economical benefits and better water solubility than tetraacetylethylenediamine. The H2O2/GT system may provide a cost-effective and environmentally friendly bleaching approach of cotton as alternative to conventional alkaline high-temperature bleaching.