A Study on Effects of Wetting-Drying on Bleached Kraft Paper Properties

Abstract

The aim of the study is to investigate effects of wetting-drying processes on bleached kraft paper properties. According to results; it has been realized that continuously wetting-drying of paper samples supplied from three different brand (A, B, and C types) effect on both physical and strength properties. However, initial stages (up to 5th cycling stages) have dramatic effects resulting in a high degree of modification, considering the fact that each following stage is moderate trend on physical properties. Contrary to breaking length and burst index that have a reducing trend as wetting-drying in progress, the tear index changed in both directions (increases or decreases). However, breaking length of samples were found to be reduced range of 11.4% to 67.8%. Nevertheless, the lowest breaking length was observed B type of papers with 1.79 km at 8th cycling stage. The lowest tear index of 2.64 mN.m2/gr was found at 5th cycling stage for C type papers while the highest tear index of 5.62 mN.m2/gr was found at 6th cycling stage for B type papers. It is clearly realized that the paper network structure are damaged and bonding potentials reduced during the wetting-drying process.