EVALUATING THE SURFACE ENERGY OF （评估的表面能）.pdfVIP

EVALUATING THE SURFACE ENERGY OF SURFACE SIZED PRINTING AND WRITING PAPERS I. Moutinho*, , P. Oliveir , M. Figueiredo , P. J. Ferreir a aChemical Engineering Department, Coimbra University, Portugal Tel. +351.239.798.700; E-mail. isamim@, paso81@, mmf@eq.uc.pt, paulo@eq.uc.pt ABSTRACT Printing quality is strongly influenced by the structural and chemical properties of paper surface, which depend not only on the properties of the base paper but also on the final treatment of paper surface. At present, surface treatment is an important step of papermaking for improving the final product quality and may comprise mechanical and/or chemical operations. For instance in uncoated printing and writing papers surface sizing is becoming a common practice for controlling paper roughness and mainly the spreading and absorption of liquids. Typically, only starch is used as sizing agent, but there is an increasing tendency for combining starch with synthetic polymers that enable a better control of the surface hydrophilic character. This study aims at analyzing the influence of different surface sizing formulations on some chemical properties of paper surface, such as energy and acid-base character. For that, seven paper samples were analyzed using two distinct techniques – Inverse Gas Chromatography (IGC) and Contact Angle Measurements. The paper surface free energy and its polar and dispersive components were assessed by measurements of the contact angle with differe