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Developing and Using Modeling to Understand and Improve Industrial Oxygen Delignification Processes, TAPPICon25

Dynamic out-of-plane compression of paperboard — Influence of impact velocity on the surface, TAPPI Journal February 2024

ABSTRACT: Processes that convert paperboard into finished products include, for example, printing, where the paperboard is subjected to rapid Z-directional (ZD) compression in the print nip. However, measuring and evaluating the relevant properties in the thickness direction of paperboard are not necessarily straightforward or easy. Measuring at relevant, millisecond deformation rates further complicates the problem. The aim of the present work is to elucidate some of the influences on the compressive stiffness. Both the initial material response and the overall compressibility of the paperboard is studied. In this project, the effect on the material response from the surface structure and the millisecond timescale recovery is explored.The method utilized is a machine called the Rapid ZD-tester. The device drops a probe in freefall on the substrate and records the probe position, thus acquiring the deformation of the substrate. The probe is also allowed to bounce several times on the surface for consecutive impacts before being lifted for the next drop. To investigate the time dependent stiffness behavior, the probe is dropped several times at the same XY position on the paperboard from different heights, thus achieving different impact velocities. The material response from drops and bounces combined allows study of the short-term recovery of the material. The material in the study is commercial paperboard. The paperboard samples are compared to material where the surface has been smoothed by grinding it. Our study shows that there is a non-permanent reduction in thickness and a stiffening per bounce of the probe, indicating a compaction that has not recovered in the millisecond timescale. Additionally, a higher impact velocity has an initial stiffening effect on the paperboard, and this is reduced by smoothing the surface.

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.

Colloidal Properties of Dissolved Kraft Lignin, 1992 Papermakers Conference Proceedings

Colloidal Properties of Dissolved Kraft Lignin, 1992 Papermakers Conference Proceedings

Beyond RCM, 2008 Engineering, Pulping and Environmental Conference

Beyond RCM, 2008 Engineering, Pulping and Environmental Conference

Liquid plasma polymerization process for improved deinkability of pigmented inkjet digital printed paper, 2012 TAPPI PEERS Conference

Liquid plasma polymerization process for improved deinkability of pigmented inkjet digital printed paper, 2012 TAPPI PEERS Conference

Optimisation of optical coverage of board surfaces with assessment of light scattering and absorption using mineral as a coating component, TAPPICon25

Pigment loading level effects on water barrier properties in barrier coating formulations, TAPPICon25

A Systems Thinking Approach: Institutional Memory Loss in Pulp and Paper Industry, TAPPICon25

Process Evaluation for Sustainability Using TAPPI TIP 0404-63, TAPPICon25