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´We Must Grow—In All Areas’, Paper360º May/June 2020
´We Must Grow—In All Areas’, Paper360º May/June 2020
Journal articles
Magazine articles
Pigmented aqueous barrier coatings, TAPPI Journal November 2020
ABSTRACT: The desire for more sustainable packaging has led to the development of new packaging materials that are fiber based. Aqueous coatings are a pathway to improve the recyclability of these materials. Pigments used in these coatings can improve the performance of the coating and reduce cost while further improving the recyclability. Mineral pigments are also considered to be compost neutral. In this paper, we provide the reader a better fundamental understanding of the mechanisms by which pigments work in barrier coatings. A pigment’s mineralogy and physical characteristics are important to how it will perform, and there have been recent pigment developments that improve coating performance. This paper shows that some pigments are better than others in particular barrier applications. Also, pigmented base or pre-coats can be used to prepare the surface for more highly functional coatings that go on top, improving the barrier function of packaging material and reducing overall cost. Finally, the converting operation is of major importance in driving formulation choices for barrier applications.
Journal articles
Magazine articles
Characterization of chia plant (Salvia hispanica) for pulping, TAPPI Journal October 2020
ABSTRACT: In this paper, chia plant was characterized in terms of chemical, morphological, and anatomical properties. Chia plant was characterized with low a-cellulose (30.5%); moderate lignin (23.2%) with syringyl to guaiacyl ratio of 1.41; and shorter fiber length (0.67 mm) with thinner cell wall (1.91 µm) and good flexibility coefficient (71.44). Anatomical features showed that chia plant consists of vessels, fibers, parenchyma cells, and collenchyma cells. Chia plant pulping was evaluated in soda-anthraquinone (soda-AQ) and formic acid/peroxyformic acid (FA/PFA) processes. Chia plant was difficult to delignify in the alkaline process. The FA/PFA process produced higher pulp yield at the same kappa number than the soda-AQ process. Unbleached soda-AQ chia pulp exhibited good properties in terms of tensile, bursting, and tearing strengths, even at the unrefined stage, due to high drainability of the pulps. Alkaline peroxide bleached FA/PFA pulp exhibited better papermaking properties and 2% higher brightness than the D0(EP)D1 bleached soda-AQ pulp.
Journal articles
Magazine articles
Incorporation of post-consumer pizza boxes in the recovered fiber stream: Impacts of grease on finished product quality, TAPPI Journal March 2021
ABSTRACT: Grease and cheese contamination of used pizza boxes has led to misunderstanding and controversy about the recyclability of pizza boxes. Some collection facilities accept pizza boxes while others do not. The purpose of this study is to determine whether typical grease or cheese contamination levels associated with pizza boxes impact finished product quality. Grease (from vegetable oil) and cheese are essentially hydrophobic and in sufficiently high concentration could interfere with interfiber bonding, resulting in paper strength loss.Findings from this study will be used to determine the viability of recycling pizza boxes at current and future con-centrations in old corrugated containers (OCC) recovered fiber streams. These findings will also be used to inform the acceptability of pizza boxes in the recycle stream and educate consumers about acceptable levels of grease or cheese residue found on these recycled boxes.
Journal articles
Magazine articles
Evaluation of rice straw for purification of lovastatin, TAPPI Journal November 2021
ABSTRACT: Cholesterol synthesis in the human body can be catalyzed by the coenzyme HMG-CoA reductase, and lovastatin, a key enzyme inhibitor, can reduce hypercholesterolemia. Lovastatin can be obtained as a secondary metabolite of Aspergillus terreus ATCC 20542. In this study, rice straw of lignocellulose was used in aeration and agitation bath fermentation in a 1-L flask, and a maximal crude extraction rate of 473 mg/L lovastatin was obtained. The crude extract was treated with silica gel (230•400 mesh) column chromatography. Ethyl acetate/ethanol (95%) was used as the mobile phase, and isolation was performed through elution with various ethyl acetate/ethanol ratios. The highest production rate of 153 mg/L was achieved with ethyl acetate/ethanol in a ratio of 8:2. The lovastatin gained from the crude extract was added to 12 fractions treated with 0.001 N alkali, and acetone was then added. After 24 h of recrystallization at 4°C, the extract underwent high-performance liquid chromatography. The purity had increased from 25% to 84.6%, and the recovery rate was 65.2%.
Journal articles
Magazine articles
Application of spruce wood flour as a cellulosic-based wood additive for recycled paper applications— A pilot paper machine study, TAPPI Journal October 2021
ABSTRACT: This study gives a first insight into the use of wood flour as a plant-based and cellulosic-based alternative additive for newsprint and paperboard production using 100% recycled fibers as a raw material. The study compares four varieties of a spruce wood flour product serving as cellulosic-based additives at addition rates of 2%, 4%, and 6% during operation of a 12-in. laboratory pilot paper machine. Strength properties of the produced news-print and linerboard products were analyzed. Results suggested that spruce wood flour as a cellulosic-based additive represents a promising approach for improving physical properties of paper and linerboard products made from 100% recycled fiber content. This study shows that wood flour pretreated with a plant-based polysaccharide and untreated spruce wood flour product with a particle size range of 20 µm to 40 µm and 40 µm to 70 µm can increase the bulk and tensile properties in newsprint and linerboard applications.
Journal articles
Magazine articles
Displacement washing of softwood pulp cooked to various levels of residual lignin content, TAPPI Journal September 2021
ABSTRACT: This study investigates the influence of the degree of delignification of kraft spruce pulp cooked at seven different kappa numbers, ranging from 18.1 to 50.1, on the efficiency of displacement washing under laboratory conditions. Although the pulp bed is a polydispersive and heterogeneous system, the correlation dependence of the wash yield and bed efficiency on the Péclet number and the kappa number of the pulp showed that washing efficiency increased not only with an increasing Péclet number, but also with an increasing kappa number. The linear dependence between the mean residence time of the solute lignin in the bed and the space time, which reflects the residence time of the wash liquid in the pulp bed, was found for all levels of the kappa number. Washing also reduced the kappa number and the residual lignin content in the pulp fibers.
Journal articles
Magazine articles
Effects of phosphogypsum whiskers modification with calcium stearate and their impacts on properties of bleached softwood paper sheets, TAPPI Journal September 2021
ABSTRACT: By combining the structural properties and characteristics of phosphogypsum whiskers, a preliminary study on the modification of phosphogypsum whiskers and their application in papermaking was carried out. The effects of reaction temperature, reaction time, and reaction concentration on the solubility and retention of modified phosphogypsum whiskers and the effects of phosphogypsum whiskers on the physical properties of paper under different modified conditions were explored. The research results show that, after the phosphogypsum whiskers are modified with calcium stearate, a coating layer will be formed on the surface of the whiskers, which effectively reduces the solubility of the phosphogypsum whiskers. The best modification conditions are: the amount of calcium stearate relative to the absolute dry mass of the phosphogypsum whisker is 2.00%; the modification time is 30 min, and the modification temperature is 60°C. The use of modified phosphogypsum whiskers for paper filling will slightly reduce the whiteness, folding resistance, burst resistance, and tensile strength of the paper, but the tearing degree and retention of the filler will be increased to some extent.
Journal articles
Magazine articles
Extension of a steady-state chlorine dioxide brightening model for Z-ECF bleaching of softwood kraft pulps, TAPPI Journal March 2021
ABSTRACT: Earlier studies developed a steady-state model to predict the brightness and/or bleach consumption during the chlorine dioxide brightening (D1) of softwood pulps produced by conventional elemental-chlorine-free (ECF) sequences. This model relates the chlorine dioxide consumed to the brightness gains predicated upon an asymptotic D1 brightness limit, an incoming D1 pulp brightness, and an equation parameter (ß11). The current investigation examines the application of this model to ECF sequences that use ozone delignification (Z-ECF). Literature D1 data from various Z-ECF bleaching studies, which investigated OZ, OD0/Z, and OZ/D0 delignification, were fitted to the model. The ß11 parameter was found to be linearly correlated to the entering kappa number. Interestingly, this linear relationship was found to be identical to the relationships observed when modeling the D1 stage for conventional ECF and chlorine-based bleach sequences. Subtle differences in D1 brightening response in the model among the various bleach sequences are reflected by incoming pulp brightness (at the same kappa number). The current model is used to illustrate how alterations to Z-ECF delignification affect D1 brightening and chlorine dioxide consumption.
Journal articles
Magazine articles
Development of converging-diverging multi-jet nozzles for molten smelt shattering in kraft recovery boilers, TAPPI Journal March 2021
ABSTRACT: The effective shattering of molten smelt is highly desired in recovery boiler systems. Ideally, shatter jet nozzle designs should: i) generate high shattering energy; ii) create a wide coverage; and iii) minimize steam consumption. This study proposes a novel converging-diverging multi-jet nozzle design to achieve these goals. A laboratory setup was established, and the nozzle performance was evaluated by generating jet pressure profiles from the measurement of a pitot tube array. The results show that the shatter jet strength is greater with a large throat diameter, high inlet pressure, and a short distance between the nozzle exit and impingement position. Increasing the number of orifices generates a wider jet coverage, and the distance between the orifices should be limited to avoid the formation of a low-pressure region between the orifices. The study also demonstrates that an optimized converging-diverging multi-jet nozzle significantly outperformed a conventional shatter jet nozzle by achieving higher energy and wider coverage while consuming less steam.