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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%.
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Rheological behavior of magnetic pulp fiber suspensions, TAPPI Journal June 2021
ABSTRACT: This paper is focused on the rheology of magnetic pulp suspensions in absence and presence of an external magnetic field. Magnetic fibers were prepared by the lumen loading method using bleached eucalyptus fibers and cobalt ferrite (CoFe2O4) nanoparticles. The effect of mass consistency, temperature, concentration of magnetic fibers, and magnetic field strength on yield stress and apparent viscosity of the suspensions were investigated. In the absence of an applied field, a dependence of yield stress with consistency, as well as with the percentage of magnetic fibers present in the suspension, was found. In flow tests, all the suspensions exhibited shear-thinning behavior, showing that the viscosity is only affected by the consistency of the suspension. On the other hand, magnetorheological measurements show a negative effect of the applied magnetic field on the viscosity of the suspension.
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Effects of different ammonium lignosulfonate contents on the crystallization, rheological behaviors, and thermal and mechanical properties of ethylene propylene diene monomer/polypropylene/ammonium lignosulfonate composites, TAPPI Journal January 2020
ABSTRACT: Thermoplastic elastomer (TPE), made from ethylene propylene diene monomer (EPDM) and polypropylene (PP) based on reactive blending, has an excellent processing performance and characteristics and a wide range of applications. However, there are currently no reports in the literature regarding the usage of TPE in making composite boards. In this paper, EPDM, PP, and ammonium lignosulfonate (AL) were used as the raw materials, polyethylene wax was used as the plasticizer, and a dicumyl peroxide vulcanization system with dynamic vulcanization was used to make a new kind of composite material. This research studied the influences of the AL contents on the crystallization behaviors, rheological properties, thermal properties, and mechanical properties of the composites. The results showed that the AL content had a noticeable impact on the performance of the composite board. Accordingly, this kind of composite material can be used as an elastomer material for the core layer of laminated flooring.
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Root cause analysis of cationic polymer additive efficiency decline in virgin and recycle containerboard mills, TAPPI Journal January 2020
ABSTRACT: It is well known that retention, drainage and strength polymers struggle to perform (if at all) in virgin containerboard mills. In-depth studies have been undertaken in this area for more than seven years, investigating the issue from all directions. A key finding of this work is that soluble lignin is detrimental to chemical efficiency. A strong correlation exists between decreased chemical efficiency and high soluble lignin. Both recycled systems and virgin systems have been studied, and this correlation holds true regardless of furnish. The primary area of concern is virgin container-board, because these mills tend to have the highest lignin levels. Some highly closed recycled mills can also build elevated lignin levels that can negatively affect chemical efficiency.
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Understanding conductivity and soda loss
Understanding conductivity and soda loss
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Editorial: Celebrating an industry giant: Dr. Peter W. Hart, TAPPI Journal April 2024
ABSTRACT: On February 19, 1915, at the annual meeting of the American Paper and Pulp Association held at the Waldorf-Astoria Hotel in New York, a group of 35 people formed a new division called the “Technical Section of the American Paper and Pulp Association” with the objectives to: (1) stimulate interest in the science of pulp and papermaking; (2) provide means for the inter-change of ideas among its members; and (3) encourage original investigation. At that meeting, Professor Ralph H. McKee of the University of Maine (1909-1916) spoke. Professor McKee had initiated the first college course in Pulp and Paper in the United States. In his remarks he stated:
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Characterizing rheological behavior and fluidization of highly refined furnishes, TAPPI Journal April 2024
ABSTRACT: In this work, highly refined softwood bleached kraft pulp (SWBKP) furnishes, referred to here as XFC, were studied from the perspective of fiber suspension handling in processing. The rheology of the furnishes was studied with a rotational rheometer using a non-standard flow geometry to understand the viscosity development at different consistencies and the impact of temperature. For fluidization analysis during pipe flow, two optical methods were implemented; namely, optical coherence tomography (OCT) and high-speed video (HSV) imaging. The OCT was used to determine the small-scale floc structures near the pipe wall where the shear stress is highest, and the HSV imaging was applied for observing flow instabilities and XFC suspension uniformity at the pipe scale. All these issues can be significant in deciding the minimum flow rate required for a process pipe to get sufficient fluidization of XFC suspensions.
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Editorial: TAPPI Journal Best Research Paper for 2023 focuses on black liquor concentration using graphene oxide membranes, TAPPI Journal February 2024
ABSTRACT: TAPPI and the TAPPI Journal (TJ) Editorial Board would like congratulate the authors of the 2023 TAPPI Journal Best Research Paper Award and Honghi Tran Prize: Sam Rae, Ella V. Richards, Max Kleiman-Lynch, Brent D. Keller, and Brandon I. Macdonald. Their paper, “Pilot scale black liquor concentration using pressure driven membrane separation,” appeared on p. 223 of the April 2023 issue. This kraft recovery cycle research was recognized by the TAPPI Journal Editorial Board for its innovation, creativity, scientific merit, and clear expression of ideas.
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Quantification of hardwood black liquor contamination in pine black liquor, TAPPI Journal February 2024
ABSTRACT: The presence of hardwood black liquor contamination in pine black liquor can negatively impact brownstock washer and evaporator operation, as well as reduce soap separation and yield. It is also believed to negatively impact commercial kraft lignin production. It was desired to develop a method of quantitatively determining the amount of low-level hardwood liquor contamination in pine black liquor. A method employing pyrolysis-gas chromatography mass spectrometry (py-GCMS) was developed to perform the desired measurement. Laboratory cooks with carefully controlled blends of pine and hardwood chips were prepared, and the resulting liquor was measured using this technique. Additionally, samples of pine and hardwood black liquors were blended in known quantities and analyzed. All these samples were submitted as blind samples. The resulting analysis suggests the py-GCMS method was able to accurately determine the level of hardwood contamination between 1% to 10% hardwood liquor using a low-level calibration curve prepared with coniferyl alcohol and sinapyl alcohol as standards.
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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.