Water Retention Value Of Fibers Research Articles

The correlation between the water retention values of fibers by the centrifugation method and maximum content of fiber bonding water by the headspace GC method

Abstract This work conducted an investigation on the water retention value (WRV) of pulp fibers measured by the conventional centrifugation method (with a screen filter) and the maximum content of fiber bonding water (MCFBW) measured by a headspace gas chromatography (HS-GC), a method with no fine loss, developed recently. The results showed there is an excellent correlation ( R 2 = 0.988 {R^{2}}=0.988 ) between these two methods. However, the WRVs measured by the centrifugation method are consistent lower than the MCFBWs from the HS-GC method and the absolute differences were significantly increases for the refined pulp fibers, i. e., about 50–70 compared to 30+ for the pulps without treatment. The information from this study provides the insight of the real WRVs of the pulps from different processes.

Effects of Alkali Swelling and Beating Treatments on Properties of Kraft Pulp Fibers

Three alkali swelling methods were used to treat two kinds of kraft pulp fibers. The morphological and chemical properties of the treated fibers were elucidated in terms of alkali concentration, with the aim of developing bulky paper and conserving wood resources. The effects of beating before and after alkali swelling were examined. The water retention value of fibers increased when higher concentrations of NaOH were used for swelling. Alkali swelling increased fiber width, while fiber length decreased. With increasing NaOH concentration, fibers became curled or kinked; the crystalline structure changed from cellulose I to cellulose II, and the crystalline index decreased. Beating before and after the alkali swelling affected the swelling behavior of kraft pulps, but there was no distinct influence on the crystalline structure. The beating treatment before alkali swelling improved the alkali swelling of fiber. However, beating after the alkali treatment diminished the alkali swelling effects. In addition, the beating after alkali swelling straightened the curled fibers.