The study on mechanism of neutral sizing (ASA/AKD) using FTIR technology

The key issue on the sizing mechanism of sizing with ASA/AKD is to confirm whether there is any reaction between ASA/AKD and hydroxyl group of cellulose to form an ester bond which orients on paper surface and makes paper have the capability of water resistance. So some compounds having hydroxyl groups, such as ethanol, glycerine and glucose, etc., were chosen to confirm if they react with ASA/AKD. FTIR was used to detect if an ester was formed in different reacting conditions. The factors considered included reaction time and temperature, their dosages, and the kinds of solvents. The results indicated that when the reaction time was four hours and the reaction temperature was approached to that on paper machines, esterifcation happened between ASA and ethanol, but ester bond was not found between ASA and glycerine, which was also the same for ASA with glucose and cellulose. For the AKD, no bonds were detected from the products of AKD and ethanol, and the same results were obtained on AKD with glycerine, glucose and cellulose.