The influence of different levels of paper roughness in spreading of water drops
Patrícia Kaji Yasumura; Song Won Park
The surface and internal paper porosities have an important effect on the paper’s ability to absorb liquids in general. The traditional methods for porosity assessment are indirect methods, based on the measurement of air flux that flows through the paper thickness. These methods are well established and standardized, however, for the new demands for paper surface studies, they are not able to completely describe the internal paper structure. The aim of this work is to evaluate the limits of application of three different methods for paper porosity assessment: the traditional and direct air-flux method, the mercury porosimetry and the microtomography. For this purpose, we analyzed five commercially available paper samples with different levels of paper surface roughness and surface treatments. The results from the traditional air permeance methods and the mercury porosimetry were numerically compared and these were qualitatively compared with the microtomograph images. The results from traditional methods and mercury porosimetry can be external porosity, dictated by surface treatments such as calendaring and coating. The internal paper structures responsible for the differences in paper pososity can be visually accessed with microtomograph images. However, this technique is still costly and time-consuming.
YASUMURA, Patrícia Kaji; PARK, Song Won. The influence of different levels of paper roughness in spreading of water drops. In: ABTCP INTERNATIONAL PULP AND PAPER CONGRESS, 45.,e IBEROAMERICAN CONGRESS ON PULP E PAPER RESEARCH, 7., 2012, São Paulo. Proceedings... 11 p.