Preparation and Performance of Fluorescein Isothiocyanate⁃Labeled Fluorescent Starch and Polyvinyl Alcohol for Warp Sizing

In order to solve the problems of low accuracy and poor variety adaptability of the current measurement method of the permeability and coating property of sizing paste in textile industry, taking starch and polyvinyl alcohol(PVA) as the representatives of the most commonly used textile sizes, various concentrations of fluorescent molecules fluorescein isothiocyanate(FITC) were used to label starch and PVA to prepare fluorescein(F)-starch and F-PVA fluorescent sizes with different degrees of labeling(DLs) for the first time, respectively. Then the starch and PVA derivatives were employed to size pure cotton warp yarns. After preparing the sections of the sized yarns, the permeability and coating percentage of starch and PVA paste to the yarns were calculated by using a fluorescence microscope and the Photoshop software, respectively. The results demonstrate that F-starch and F-PVA with appropriate DL of 0.791% and 0.161%, respectively, exhibit good fluorescence property and similar sizing performance to the sizing performance of unlabeled starch and PVA. It is considered that fluorescence labeling of sizing agents with fluorescein units can provide an innovative way for the accurate determination of the permeability and coating property of sizing paste to warp yarns.