Individual Fiber Strength of Wood Pulp

Usuda, Makoto; Ikeda, Shigeo; Navarro, Jaime R.; Nakano, Junzo; Migita, Nobuhiko

doi:10.2524/jtappij.20.5_257

Cited by 6 publications

(2 citation statements)

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“…Hult et al [57] investigated the hierarchic organization of cellulose microfibrils in kraft and sulfite pulp fibers and showed that the kraft fibers exhibit higher ordered cellulose and more aggregated fibrils in contrast to the sulfite fibers. This may well contribute to the better mechanical properties of the kraft fibers, both in terms of stiffness and strength [58]. A process optimized for composite application should aim to improve or at least retain as much as possible of the high intrinsic cell-wall stiffness, and not, as is the case for paper application, increase the flexibility to achieve large contact areas between the fibers.…”

Section: Fiber Stiffness and Specific Comparison Of Fibersmentioning

confidence: 99%

Stiffness Contribution of Various Wood Fibers to Composite Materials

Neagu

Gamstedt

Berthold³

2006

Journal of Composite Materials

108

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Wood pulp fibers can serve as useful reinforcement of plastics for increased stiffness. To assess the potential of various wood fibers as reinforcement, a method has been developed to determine the contribution of the fibers to the elastic properties of the composite. A micromechanical composite model and classical laminate mechanics are used to relate the elastic properties of the fibers to the elastic properties of the composite. A large variety of composites made of various wood pulp fibers in an epoxy vinyl ester matrix was manufactured. From the tensile test results of the composites, the contributing Young’s moduli of the fibers in the longitudinal direction are back-calculated and summarized. One finding is that there is an optimum in fiber stiffness as a function of lignin content. It is also found that industrially pulped hardwood fibers have higher stiffness than the corresponding softwood fibers. One example is kraft-cooked Norway spruce fiber, for which a Young’s modulus of 40 GPa is found. The effects of hornification, prehydrolysis, and sulfite processing are also investigated. The results indicate that mild defibration process should be used, that does not damage the cell wall structure so that the inherent high stiffness of the native fibers can be retained. It can be concluded that the proposed method works well to rank the wood fiber candidates in terms of their contribution to the composite stiffness.

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Section: Fiber Stiffness and Specific Comparison Of Fibersmentioning

confidence: 99%

Stiffness Contribution of Various Wood Fibers to Composite Materials

Neagu

Gamstedt

Berthold³

2006

Journal of Composite Materials

108

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“…The zero-span tensile strength improved slightly for both the original pulp and TOPs after refining treatment ( Table 2) . The zero-span tensile strength is affected by the interfiber bonding areas in sheets [12][13][14] . Therefore, an increase in interfiber bonding areas by refining slightly improves the zero-span tensile strength.…”

Section: Fiber Strengthmentioning

confidence: 99%

Characterization of TEMPO―Oxidized and Refi ned Pulps （Part 2）

et al. 2019

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Hardwood bleached kraft pulp was oxidized using a TEMPO/NaBr/NaClO system to prepare two TEMPO oxidized pulps (TOPs) with similar amounts of aldehyde groups but different amounts of carboxy groups. The original pulp and TOPs were refi ned using a PFI mill at various revolution numbers, and the influence of refining conditions on the fundamental properties of TOP sheets was investigated. The tensile strength of TOP sheets was higher than that of the original pulp sheet prepared using the same PFI mill revolution numbers. Refi ning of TOPs signifi cantly improved wet tensile strength of the TOP sheets, whereas the original pulp did not exhibit such eff ect by refi ning. A clear relationship existed between the wet strength and the amount of aldehyde groups in the pulps. These results can be explained by the formation of hemiacetal linkages between the hydroxy and aldehyde groups at the interfi ber bonds in the sheets, which resulted in the increase in the wet strength of the TOP sheets. These results also indicated that refi ning is benefi cial for improving wet tensile strength when TOPs are used for papermaking.

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