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Journal articles
Improving barrier performance of coated paper and paperboard
ABSTRACT: Market demand for barrier coated packaging paper and paperboard has been on a steady rise and is forecasted to further increase. As a result, there is a continued interest in improving barrier coating functionalities, which is currently an active area of investigation. In this work, a multi-layer approach was adopted that involved applying a biowax emulsion, latex, or a combination of biowax and latex top coating layer onto the kaolin/latex (20/80, 50/50, 65/35, or 70/30) precoated solid bleached sulfate (SBS) paperboard. Our main objective was to demonstrate the effect of these top coating layers on various barrier properties, especially water vapor transmission rate (WVTR) at high relative humidity (RH) and high temperature (90% RH; 38°C), known as tropical/jungle test conditions. While the top coat with latex and/or biowax showed dramatic improvement in both water resistance (Cobb) and WVTR, the biowax coating increased contact angle significantly compared to the latex top coat. Contact angle increased from about 65° for the latex top coat to as high as 96° for the biowax top coat. Generally, it is much more difficult to improve WVTR at the jungle conditions below 100 g/m2/day, even with the high aspect ratio platy pigment. However, using the coating strategies adopted in this study, we were able to achieve WVTR values notably below 50 g/m2/day at the tropical test conditions, as well as significant improvements in regard to fold crack barrier integrity at high kaolin clay usage.
Journal articles
Prediction of residual calcium carbonate (CaCO3) in the lime
ABSTRACT: In a kraft pulp mill, the rotary lime kiln is responsible for converting calcium carbonate (CaCO3) into calcium oxide (CaO) to be reused in the causticizing plant. An important parameter of the calcination efficiency and the product quality is the amount of CaCO3 not converted to CaO, commonly defined as residual carbonate. This parameter is usually determined through laboratory analysis, which introduces delays in process control and limits the ability to make timely operational adjustments. This work presents a predictive model that functions as a soft sensor for the residual carbonate in a lime kiln of a Brazilian kraft pulp mill. This model was able to estimate residual CaCO3 every 30 min using routinely measured online process variables, which is a considerable reduction from the 6-h average laboratory measurement. The correlation coefficient (r) between the model predictions and the mill values was 0.83, with a mean absolute error (MAE) of 0.33%. Considering the effect of the residence time throughout the lime kiln proved to be decisive in obtaining a satisfactory prediction result. After model validation, a variable importance analysis showed that the carbon monoxide (CO) concentration in the stack flue gas (in ppm), secondary air temperature (in oC), and fan speed (in %) were the most influential variables in predicting the residual carbonate content. Combined with commonly used operation expertise, this subset of variables can serve as additional information to achieve smoother lime kiln operation.
Journal articles
Magazine articles
Multifunctional starch-based barrier materials, TAPPI Journal August 2021
ABSTRACT: Natural and renewable polymer-based barrier materials play an inevitable role in a sustainable economy. Most commercially available barrier materials are either based on multiple layers of synthetic polymers or petroleum-based chemicals. Tremendous amounts of research are being done in academia and industry to replace these synthetic barrier materials with natural and environmentally friendly materials. The current work summarizes the application of starch-based materials for various barrier applications, such as water vapor, oxygen, liquid water, oil, and grease. Also, exotic starch-based barrier materials for the application of sound, ultraviolet, and thermal barrier applications are reviewed. The potential of starch-based materials to offer antimicrobial and antiviral properties is discussed. Finally, commercially available starch-based barrier materials have been summarized.
Journal articles
Infrared Microspectroscopy: Analysis of Multilayer Films, Co
Infrared Microspectroscopy: Analysis of Multilayer Films, Contaminants and Inclusions, 1990 Polymers, Laminations & Coatings Conference Proceedings
Journal articles
Characterizing Hot-Tack Differences in Hot-Melt Adhesives Us
Characterizing Hot-Tack Differences in Hot-Melt Adhesives Using DMTA, 1991 Polymers, Laminations & Coatings Conference Proceedings
Journal articles
Historical and Recent Attempts to Solve the Uneven Microwave
Historical and Recent Attempts to Solve the Uneven Microwave Heating Problem with Packaging, 1991 Polymers, Laminations & Coatings Conference Proceedings
Journal articles
In-Line Shear Viscosity Measurements for the Gear Pump Assis
In-Line Shear Viscosity Measurements for the Gear Pump Assisted Extrusion Process, 1992 Polymers, Laminations & Coatings Conference Proceedings
Journal articles
Identification of the Source and Chemical Identity of Chromo
Identification of the Source and Chemical Identity of Chromophores Present in Polyethylene Lamination, 1993 Polymers, Laminations & Coatings Conference Proceedings
Journal articles
Wetting Tension Measurements on Corona-Treated Polymer Films
Wetting Tension Measurements on Corona-Treated Polymer Films, 1994 Polymers, Laminations & Coating Conference Proceedings
Journal articles
Technical Evaluation: Methods for Sealing Paper/Foil Aseptic
Technical Evaluation: Methods for Sealing Paper/Foil Aseptic Food Packages, 1996 Polymers, Laminations & Coatings Conference Proceedings