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Journal articles
Magazine articles
Effects of carboxymethyl starch as a papermaking additive, TAPPI Journal February 2024
ABSTRACT: Carboxymethyl starch (CMS) is a bio-based, anionic polymer that has potential as part of a dry-strength additive program for papermaking. Due to its negative charge, its effects can be expected to depend on its interactions with various cationic agents. In this work, the effects of CMS were observed following its sequential addition after one of three selected cationic strength agents at different dosage levels. In selected tests, the furnish was pretreated at the 1% level by a dispersant, sodium polyacrylate, which might represent a high level of anionic contaminants in a paper mill system. Laboratory tests were conducted to show the effects on dewatering, fine-particle retention, and flocculation. These tests were supplemented with measurements of charge demand, zeta potential, and handsheet properties. Sequential addition of cationic glyoxylated acrylamide copolymers (gPAM) and CMS were found to strongly promote dewatering. Two gPAM products and a poly(vinylamine) product in sequential addition with CMS were very effective for promoting fine-particle retention. These same sequential treatments of the stock contributed to moderate fiber flocculation, though severe flocculation was caused by further treatment of the furnish with colloidal silica. Handsheet strength results were mixed. In the default recycled copy paper furnish, the average breaking length for the sheets made with cationic additives followed by CMS was not greatly different from the blank condition. Superior strength resulted when the default furnish was treated with a dispersant alone. When the dispersant-contaminated furnish was treated with the same combinations of cationic additives and CMS, the strength returned to the baseline achieved in the absence of the dispersant. The results were discussed in terms of the charged character of the different additives and their interactions not only with the fiber surfaces but also with each other.
Journal articles
Magazine articles
Continuous digester rapid thinning, TAPPI Journal June 2024
ABSTRACT: Carbon steel continuous digesters built after the early 1980s are fully stress relieved, so stress corrosion cracking has been less of a concern. However, these newer digesters were designed to run modified cooking processes that have turned out to be much more corrosive than those running with conventional cooking. This corrosion is mainly associated with softwood digesters and appears to be flow related. Average corrosion rates of 40 mil/year are possible on the exposed shell between the wash and extraction screens. The corrosion patterns are visually distinct from surfaces in the upper digester and below the wash screens. This paper goes into practical detail on where it occurs, the causes, visual identification, inspection planning and results evaluation, and finally, how to mitigate this damage, which consists of applying a corrosion resistant barrier. Some discussion on dealing with general corrosion throughout the digester is included.
Journal articles
Enhancing douglas-fir pulp properties with a combination of enzyme treatments and fiber fractionation, TAPPI JOURNAL, May 1999, Vol. 82(5)
Enhancing douglas-fir pulp properties with a combination of enzyme treatments and fiber fractionation, TAPPI JOURNAL, May 1999, Vol. 82(5)
Journal articles
On-line measurement of ozone consumption rate during high-consistency bleaching, TAPPI JOURNAL, October 1999, Vol. 82(10)
On-line measurement of ozone consumption rate during high-consistency bleaching, TAPPI JOURNAL, October 1999, Vol. 82(10)
Magazine articles
Inside ctapi, TAPPI JOURNAL, May 1996, Vol. 79(5)
Inside ctapi, TAPPI JOURNAL, May 1996, Vol. 79(5)
Magazine articles
Building a team: the cedar river project, TAPPI JOURNAL, November 1996, Vol. 79(11)
Building a team: the cedar river project, TAPPI JOURNAL, November 1996, Vol. 79(11)
Journal articles
Polymer enhanced brownstock washing: mill trial, TAPPI JOURNAL, November 1996, Vol. 79(11)
Polymer enhanced brownstock washing: mill trial, TAPPI JOURNAL, November 1996, Vol. 79(11)
Journal articles
Silicate chemistry key to solving mill scale problems, TAPPI JOURNAL, November 1996, Vol. 79(11)
Silicate chemistry key to solving mill scale problems, TAPPI JOURNAL, November 1996, Vol. 79(11)
Journal articles
Twenty-five years of global progress in nonwood plant fiber pulping, TAPPI JOURNAL, October 1996, Vol. 79(10)
Twenty-five years of global progress in nonwood plant fiber pulping, TAPPI JOURNAL, October 1996, Vol. 79(10)
Journal articles
Bale wrapper gluing as a safe alternative to wire tying, TAPPI JOURNAL, September 1996, Vol. 79(9)
Bale wrapper gluing as a safe alternative to wire tying, TAPPI JOURNAL, September 1996, Vol. 79(9)