Structure and characterization of carbonized cotton knitted fabric

Abstract

Carbonized cotton fabrics have been used in the preparation of wearable sensors. However, there are few studies on the carbonization structure and properties of carbonized cotton fabric. This work provided a practical and effective method for the preparation of carbonized cotton knitted fabrics. The effects of impregnating agents and pre-oxidation on the carbonization structure and performances of the cotton knitted fabric were investigated systematically for the first time. Thermal gravimetry analysis revealed that cotton knitted fabric impregnated with 10% (NH4)2HPO4 had a higher carbonized yield of cotton knitted fabric than that with 5%, which was followed by 10% NH4H2PO4, and the worst was 10% (NH4)2SO4. The results also showed that the carbonized yield of cotton knitted fabric was enhanced considerably at 900°C for 120 min after impregnation with 10% (NH4)2HPO4 and pre-oxidation at 240°C for 60 min. The integrity of the cotton knitted fabric was maintained after carbonization. Scanning electron microscopy showed that the natural turn of carbonized cotton fiber was deepened after being impregnated with 10% (NH4)2HPO4 and pre-oxidized at 240°C for 60 min. With the increase of carbonization temperature, C-O and C-H were destroyed, and C=C bonds were formed. The amorphous carbon interlayer was created after carbonization. The structural order of these carbonized cotton fibers was improved with the enhancement of temperature. Pre-impregnation agent treatment and pre-oxidation greatly heightened the carbonized yield of cotton knitted fabric, maintained the integrity of the carbonized cotton fiber, and then increased the electrical conductivity of the carbonized cotton knitted fabric.