No description available.

No description available.

No description available.

A series of laboratory oxygen delignification were performed in this study at constant oxygen pressure and consistency to study the response of the pulp to the different process parameters, i.e. reaction temperature, reaction time, soda addition, and mechanical pretreatment, to the zero span tensile strength loss. The basic chemistry of the oxygen delignified pulps was under study including fiber charge, celluloses/hemicelluloses, and hexenuronic acid. The fiber structure such as curl, kink, fines, and fiber length were also discussed. NaOH charge can be reduced as much as 50 % by applying mechanical pretreatment to obtain the same level of selectivity at the oxygen delignification conditions described in this study.Mechanical pretreatment prior to oxygen delignification promoted a better selectivity for both Acacia mangium and MHW pulps. MHW kraft pulp did not show a significant extractive removal in all pretreatment methods during oxygen delignification. The ultrasonic pretreatment followed by filtering induced the best extractive removal among the other three methods.

The wicking properties of multi-ply paper samples with dissimilar plies were investigated. These materials exhibit wicking performance in excess of either of their individual plies. Samples were produced from a ply of softwood pulp and a ply of hardwood pulp of equal caliper and basis weight. The softwood sample possessed a larger average pore size, a fact verified via porometry. Samples of a single ply were also produced for comparison. The samples were tested using both upward and downward gravimetric wicking tests. There was no saturation gradient observed, however there was a variation in the degree of bulk expansion during wicking. Capillary pressure and permeability for the various sample types were determined from the results of these tests and compared. It is shown that the wicking performance of the two ply sample is comparable to that of a theoretical material with the capillary pressure of the hardwood ply but the permeability of the softwood ply. Wicking in two-ply samples was also observed in an NMR apparatus. This was used to determine that the hardwood ply leads during wicking, and observe the rate of saturation as well as bulk expansion. A third type of experiment tracked the transport of dyed water from one ply to the other, establishing the direction of fluid transport during wicking to be from the softwood ply to the hardwood ply. The theory is proposed, based on these results, that wicking in this type of material consists of a smaller pored leading ply that draws water from a more permeable larger pored material that acts as a moving reservoir.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1940. / Includes bibliographical references (p. 75-77).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1951. / Includes bibliographical references (p. 221-223).

Thesis (Ph. D.)--Institute of Paper Science and Technology, 1989. / Includes bibliographical references (p. 169-177).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1966. / Includes bibliographical references (p. 102-106).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1942. / Includes bibliographical references (p. 97-99).