Objective differentiation of washed and unwashed cottons by thermal analyses

Washed and unwashed cottons grown in Mississippi, Texas, or California were tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The effects of temperature and ratio of water to cotton in cleaning were investigated, as was the use of a scouring process. DSC detected washing readily, as exotherms for all raw cottons were replaced by endotherms for all washed samples. TGA could also detect washing primarily by measuring the amount of residue: unwashed cotton had about 50% more residue than washed cotton. Other, more subtle differences were also detected by both DSC and TGA.