Effect of Hot Water Extraction on Hardwood Kraft Pulp fibers (Acer saccharum, Sugar Maple)

Abstract

This study focuses on the properties of fibers obtained from the kraft pulping of pre-extracted sugar maple wood chips. Hot-water pre-extraction was carried out for different times characterized by P-factors in the range of 12 and 600 h. It was found that pre-extraction of the chips significantly accelerates delignification during Kraft pulping such that the H-factors necessary to obtain equivalent delignification (i.e., the same κ numbers) were substantially smaller than control cooks (i.e., with unextracted chips). Unbleached pulps of κ numbers of 35, 25, and 15 were prepared, and their papermaking properties were tested. The hemicellulose content of the pulps decreased with pretreatment, whereas the cellulose contents increased. Pretreatment also resulted in an increase in the pulp viscosity. The fiber lengths showed no change, but the fines content was reduced. The kink index of pre-extracted pulps showed large increases. The porosity of the cell wall also increased with extraction severity as did the mean pore size. The water retention values (WRV) also increased with extraction probably because of the increased fiber porosity. The ζ potential of the fines remained unaffected, whereas the total charge (cationic) demand of the pulps decreased with pre-extraction. There is also a significant loss of tensile and burst strengths of handsheets made with extracted pulps possibly as a consequence of the increased kink and curl index and decreased interfiber bonding ability.

Comparison of hot-water extraction and steam treatment for production of high purity-grade dissolving pulp from green bamboo

“…From a mathematical perspective, the algebraic expressions for P-factor and H-factor are obviously quite similar, while that for the severity factor (R 0 ) is somewhat different [Supplemental B (part 2)]. Based on this consideration, recently, Duarte et al (2011) introduced P-factor and H-factor into the traditional delignification kinetic model. Good agreement between the predicted and experimental kappa numbers of PHK pulps with different prehydrolysis severities was achieved.…”

Purification of cellulosic pulp by hot water extraction

“…Under intense extraction conditions, however, the extensive cleavage of glycosidic bonds in cellulose results in a reduction of its DP and the formation of new reducing end-groups. A reduction in cellulose DP appears to occur even when mild extraction conditions are applied (Duarte et al 2011). In a subsequent alkaline pulping process, particularly following an intense HWE, the yield of cellulose dramatically decreases due to peeling reactions that start at the reducing ends (Borrega et al 2013a;Testova et al 2013).…”

Preparation and characterization of cellulose and microcrystalline cellulose isolated from waste Leucaena leucocephala seeds

“…Removal of primary and secondary metabolites was done according to Duarte et al (2011) with some modifications. The LLS seed waste were grounded to powder and suspended in distilled water followed by extraction with boiling water under reflux.…”