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Alkyl ketene dimer (AKD) sized paper reversion due to oxidative photodegradation, TAPPI Journal January 2024

ABSTRACT: Alkyl ketene dimer (AKD) is a sizing agent used in papermaking to increase the resistance of paper-board towards water penetration. The acquired hydrophobic property of the paper can be reversed due to the instability of the sizing agent. It is broadly known that AKD size reversion is due to migration, poor orientation, masking, or hydrolysis of the sizing agent. Unfortunately, the environmental parameters that cause this chemical instability are not well understood. Thus, the conditions that initiate or catalyze AKD size reversion and the mechanisms of AKD size reversion under different environmental conditions need to be investigated. In this study, six different experimental setups were used to investigate how temperature, daylight, fluorescent light, oxygen, and ultraviolet (UV) light affect AKD size reversion. Cobb values and pyrolysis gas chromatography-mass spectrometry (py-GCMS) results show that AKD size reversion is due to the degradation of the chemical in the presence of light and oxygen; temperature variations were found to accelerate reversion in the presence of light and oxygen. The oxidative photodegradation mechanism of the sizing agent is explored, and a possible mechanism is proposed.

Amphoteric dry strength chemistry approach to deal with low-quality fiber and difficult wet-end chemistry conditions in the Asian and North American markets, TAPPI Journal January 2024

ABSTRACT: With Japan’s high recycling rates and low access to fresh fiber sources, reaching strength targets in manufacturing packaging materials is a challenge. Declining quality of recycled fiber and minimal freshwater con-sumption results in difficult wet-end chemistry conditions in terms of high conductivity and elevated levels of dissolved and colloidal substances (DCS). These trends are somewhat typical of other Asian regions. Due to global trade, Asian packaging materials have become a part of the North American (NA) raw material pool. The gradual closing of mill water circuits for fresh water and energy savings results in more difficult wet-end chemistry conditions experienced in North America. China’s ban on the import of mixed paper and the consequent ban on all waste-paper imports triggered a significant price drop in recycled raw material, resulting in plans for increased manufacturing capacity in North America. Between increased demand, decreasing fiber quality, and movement towards more closed white water systems associated with packaging grade paperboard (even a virgin fiber mill uses a fair amount of recycled fiber), new methods to overcome strength reduction in raw materials must be proactively considered for North America. Reviewing the strategies currently used in the Asian industry regarding strength development is an excellent starting place for NA producers. A clear difference between Asian and NA wet-end chemistry is the dominant position of amphoteric dry strength agents. This paper reviews the fundamentals of dry strength development that explain the trend towards the increased application of amphoteric dry strength technology for poor-quality fiber and highly contaminated water circuits in Asian markets. This paper discusses the development and application perfor-mance of the novel 4th generation amphoteric polyacrylamide (AmPAM) dry strength technology, based on selected laboratory and mill case studies.

Steel Cylinders are Key to Hitting Sustainability Targets, Paper360º January/February 2024

Why Use the Technical Database in Planning and Scheduling?, Paper360º January/February 2024

Editoral: Investing in the future: Writing and peer-reviewing for TAPPI Journal, TAPPI Journal July 2024

ABSTRACT: Those who actively participate in TAPPI realize how much there is to gain from the networking, educational resources, career development, and other opportunities that come with this involvement. One important opportunity is the ability to share your work and expertise with others in your field, and an excellent way to do this is by taking part in the TAPPI Journal peer-review process, either as an author or a reviewer or both.

Mitigating Malodors at Pulp and Paper Production Plants, Paper360º July/August 2024

Growth and Opportunity for Mainline Conveyor Systems, Paper360º July/August 2024

NA’s First Smelt Spout Robot Elevates Safety, Productivity, Paper360º March/April 2024

Unlocking Profit Potential: How US Pulp Mills Can Capitalize on Carbon Capture, Paper360º May/June 2024

Orifice geometry as a tool for evaluating extensional flow resistance of barrier coating colors, TAPPI Journal November 2024

ABSTRACT: Knowledge of extensional flow behavior of coating colors can be beneficial for improving runnability and eliminating defects in various coating processes. The current work evaluates the use of an orifice geometry attached to a commercial capillary viscometer as a tool to obtain extensional flow properties of barrier coating dispersions. By measuring the pressure drop across the orifice as a function of flow velocity, the method presents the flow resistance as Euler number at industrially relevant high deformation rates. The results agree with the earlier results obtained with a capillary entrance pressure loss technique. The type of polymer additive is shown to control the extensional flow resistance, with high molecular weight linear flexible polymers such as polyethylene oxide (PEO) and polyvinyl alcohol (PVOH) having highest impact. The orifice method offers advantages over other approaches, including the need for only a small sample amount, ease of measurement, and access to high deformation rates.