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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.
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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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Editorial: Collaboration: A necessary recipe for technological growth, TAPPI Journal September 2021
ABSTRACT: Ongoing crisis situations, such as COVID-19 and the oil spill on the Orange County beaches in California, clearly highlight the need for various forms of collaboration, be it technical or trade. Technological growth in any sector these days depends on knowhow from multiple fields.
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Guest Editorial: Terry Bliss: Editorial board member "extrem
Guest Editorial: Terry Bliss: Editorial board member "extreme", TAPPI JOURNAL May 2012
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Editorial: A PaperCon preview of what’s coming in April, TAPPI Journal February 2020
Coming soon is PaperCon—TAPPI’s annual technical conference for paper and pack-aging industry professionals. Held this April 26-29 in Atlanta, GA, the conference features sessions on management, coating and graphic arts, process control, recycled paperboard, and a wide range of papermaking topics. Universities and research organizations from around the world are represented in the conference content, and below is a preliminary sampling of just a few of the many presentations that might interest TAPPI Journal readers.
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The winding mechanics of laminate webs, TAPPI Journal February 2020
ABSTRACT: Models that describe the residual stresses due to winding single-layer webs at the end of roll-to-roll manufacturing machines are mature. These models have been used to reduce or avoid defects that are due to winding. Many laminated products exist where two or more webs have been joined to form a thicker composite web. The properties of the web layers provide a unique functionality to the product being manufactured. No laminate winding models exist in the literature. This paper will focus on the development of a laminate winding model and laboratory test verification of the model.
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A new approach for the preparation of cellulose nanocrystals from bamboo pulp through extremely low acid hydrolysis, TAPPI Journal January 2020
ABSTRACT: As a renewable and biodegradable nanomaterial, cellulose nanocrystal (CNC) has a wide range of potential applications, but production of CNC faces significant challenges in capital investment and manufacturing cost. In this work, the one-step preparation of CNC from bleached kraft bamboo pulp by extremely low acid (concen-tration of acid = 0.1 wt%) hydrolysis was demonstrated. The experimental data indicated that the yield of CNC was strongly affected by the operating pressure and concentration of hydrochloric acid (HCl), as well as temperature. Rod-like CNC with a mean particle size of 524 nm was obtained through an extremely low acid (ELA) hydrolysis pro-cess. The yield of CNC can reach to 37.1% by an ELA hydrolysis process at 180°C for 60 min with 0.08 wt% HCl and 20 MPa operating pressure. The Fourier transform-infrared spectroscopy (FTIR) measurements show that the as-pre-pared CNC maintained cellulose structure. Compared with a conventional CNC prepared by strong sulfuric acid (H2SO4) hydrolysis, the CNC prepared by ELA hydrolysis process exhibited much higher thermal stability.
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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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Equilibrium moisture content in wet pressing of paper, TAPPI Journal July 2020
ABSTRACT: Equilibrium moisture is a limiting factor in achieving high solids in the later stages of pressing or pressing low basis weight grades. We have developed a model that relates equilibrium moisture directly to the pore size distribution of fibers as measured by the solute exclusion technique. The model shows that chemical pulping and refining increase equilibrium moisture by increasing pore volume at given pore sizes in fibers, which leads to lower pressed solids and greater energy expenditure in the dryer section. Means to increase equilibrium moisture without compromising pulp strength are briefly discussed.
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Combatting lime kiln ringing problems at the Arauco Constitución mill, TAPPI Journal July 2020
ABSTRACT: The lime kiln at the Arauco Constitución mill experienced severe ringing problems requiring it to be shut down for ring removal every 3 to 6 months. The mill controlled the problems by blasting ring deposits off during operation with its existing industrial shotgun and a newly installed Cardox liquid carbon dioxide (CO2) cartridge system. Various ring blasting procedures were tested to determine the optimum ring location and thickness to blast; the optimum depth to insert the CO2 cartridge into the kiln; and the most effective blasting frequency and sequence to employ. The best strategy was found to be the weekly blasting operation that alternated between the liquid CO2 cartridge and the industrial shotgun, with the CO2 cartridge inserted into the ring mass, 20 cm (8 in.) away from the refractory brick surface, and the shotgun aimed at rings at about 28 m (92 ft) from the kiln discharge end. With each blasting event removing considerably more rings than before, it takes a longer time for rings to rebuild, allowing the kiln to run continuously between annual maintenance shutdowns with only a few short (< 4 h) downtimes for ring removal. This substantially reduces the costs associated with ring removal and lime replacement during unscheduled shutdowns.