The adhesion of wet fibers is usually explained by the presence of capillary forces, which keep the swollen fibers together. These bonds are due to the free water present outside the wall of the swollen fibers. However, what happens when the free water is being removed and the tensile strength of the wet web continues to increase is not well understood. Tensile strength's measurements of refined fibers in presence of polyelectrolytes and mineral particles suggest that no enhancement of bonding occurs between the fibers when the free water is gone. The addition of microfibrils tends to enhance the wet web strength. This indicates strongly that fiber entanglement due to mechanical interactions may be the major interaction responsible for keeping the swollen fibers together in the transient region where neither capillary forces nor hydrogen bonding dominate. / The interactions between fibers, precipitated calcium carbonated (PCC) and retention aids, revealed that the wet web strength of PCC-filled handsheets is detrimental in the presence of flocculated PCC particles, while no detrimental effect is observed in the presence of stable PCC particles. Friction generated by the deposition of small and/or single particles on the fiber surface can explain their enhancement of strength, whereas bigger particles may prevent the entanglement of fibers. Finally, the addition of polyelectrolytes to swollen fibers reduces the wet web strength. The presence of an additional polymer layer results in an increased electrosteric repulsion between fibers, which decreases the friction between fibers. This reduction of friction makes the fibers slide more easily over each other, resulting in poor wet web strength.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.101155 |
| Date | January 2007 |
| Creators | Oliveira, Marcius Henrique de. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Chemical Engineering.) |
| Rights | © Marcius Henrique de Oliveira, 2007 |
| Relation | alephsysno: 002612643, proquestno: AAIMR32764, Theses scanned by UMI/ProQuest. |
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