1999 Spotlight on Graduate and Undergraduate Research at ESF
Paper Science Engineering Abstracts

THE EVALUATION OF FILM THICKNESS BY USING LASER PROFILOMETER. Yong-Joo Sung, Eric Breternitz and Dr. D. Steven Keller.

THE INFLUENCE OF ALKALINE PULPING CONDITIONS ON OXYGEN DELIGNIFICATION. Rallming Yang and Yuan-Zong Lai.

THE EVALUATION OF FILM THICKNESS BY USING LASER PROFILOMETER. Yong-Joo Sung, Eric Breternitz, and Dr. D. Steven Keller, Department of Paper Science and Engineering, SUNY-ESF, Syracuse, NY 13210.

     The Thickness of polymeric films on paperboard is an important property for milk carton and food grade products. An Laser profilometer was used to determining the local thickness of transparent film coatings to a resolution of 10 micrometers. This instrument was composed of a positioning stage and a non-contact laser triangulation sensor, which determined the position of top and bottom surfaces by beam reflection. Polyethylene coated papers and boards, such as milk cartons with film thickness from 20 to 100 µm were tested. The coating film profiles scanned by laser profilometer were compared with the profiles obtained from image analysis of cleaved cross sections of the same sample. The image of cross section was taken by using SEM. The results showed the applicability of laser profilometer to measuring the local thickness of transparent film.

THE INFLUENCE OF ALKALINE PULPING CONDITIONS ON OXYGEN DELIGNIFICATION. Rallming Yang and Yuan-Zong Lai, Faculty of Paper Science and Engineering, Empire State Paper Research Institute, 425 Walters Hall, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210.

     One of the technical challenges in kraft process is how to effectively remove the last 10% of lignin while maintaining the fiber quality. Although oxygen bleaching has became a preferable process to follow kraft pulping, it can only readily delignify approximately 50% of the residual lignin without causing an excessive fiber degradation. We have been interested in understanding controlling factors affecting the efficiency of oxygen delignification.
     Our recent studies indicate that the alkaline pulping conditions have a significant influence on the reactivity of residual lignin toward oxygen bleaching. These cooking variables include the type of pulping process, the extent of alkaline delignification, and the additions of additives. It appears that the overall oxygen bleaching efficiency may be improved by a proper combination of the kraft and delignification conditions.