Search
Use the search bar or filters below to find any TAPPI product or publication.
Filters
Content Type
Publications
Level of Knowledge
Collections
Journal articles
Magazine articles
Progress in foam forming technology, TAPPI JOURNAL August 2019
ABSTRACT: This paper summarizes recent developments in foam forming that were mainly carried out in pilot scale. In addition to improving the efficiency of existing processes and allowing better uniformity in material, a wide variety of raw materials can be utilized in foam forming. The focus of this paper is thin webs—papers, boards and foam-laid nonwovens, along with the pilot scale results obtained at VTT in Finland. For paper and board grades, the most direct advantage of foam forming is the potential to produce very uniform webs from longer and coarser fibers and obtain material savings through that. Another main point is increased solids content after a wet press, which may lead to significant energy savings in thermal drying. Finally, the potential to introduce “difficult” raw materials like long synthetic or manmade fibers into a papermaking process enables the manufacturing of novel products in an existing production line. This paper also briefly discusses other interesting foam-based applications, including insulation and absorbing materials, foam-laid nonwovens, and materials for replacing plastics.
Journal articles
Magazine articles
Editorial: Let's talk tissue!, TAPPI Journal July 2019
ABSTRACT: In this issue of TAPPI Journal (TJ), researchers Olejnik and Pelczynski of Lodz University of Technology in Poland and researcher Bloch of the University of Gre-noble Alpes in France use an experimental device to measure the liquid absorption properties of tissue (p. 417). The device, called the eXtended liquid penetration analyzer (XLPA), was initially built at the Institute of Papermaking and Printing at the University of Lodz. Results from the study published here showed that the XLPA measurements were in good agreement with the ISO 12625:-8:2010 standard measurements. The researchers believe this method could ultimately help mills characterize the liquid absorption of their tissue in a better and faster manner.
Journal articles
Magazine articles
Kraft pulp bleaching with a P-stage catalyzed by both bicarbonate and TAED, TAPPI Journal July 2019
ABSTRACT: Peroxide bleaching of softwood and hardwood (eucalypt) kraft pulps was performed in solutions of sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3), and sodium hydroxide (NaOH). The conventional P stage (hydrogen peroxide + sodium hydroxide; H2O2 + NaOH) was the most effective brightening system without an additional activator. However, peroxide activation by bicarbonate anion (HCO3•) was obvious in all cases where NaHCO3 or Na2CO3 was used. When N,N,N’,N’-tetraacetylethylenediamine (TAED) was added to the bleaching sys-tem, Na2CO3 as the alkali source afforded equal or slightly higher bleached brightness compared to NaOH usage for both the softwood and hardwood pulps. This outcome is attributed to simultaneous peroxide activation by HCO3• and TAED. When applied to the eucalypt pulp, the H2O2/Na2CO3/TAED bleaching system also decreased the bright-ness loss due to thermal reversion.
Journal articles
Magazine articles
Enhancement of processability, surface, and mechanical properties of paper based on rice straw pulp using biopolymers for packaging applications, TAPPI Journal July 2019
ABSTRACT: wo biopolymers, chitosan and oxidized starch, were used as wet-end additives to improve the strength properties of the paper because of their biodegradable and non-hazardous qualities. The present study reports the improvement in surface and strength properties of packaging-grade paper made with rice straw pulp using biopolymers, chitosan, oxidized starch, and surface sizing added at the wet end of the paper machine.Use of chitosan at all doses from 0.5 to 10 kg/ton enhanced important surface and strength properties of paper. The breaking length, tear index, burst index, ring crush strength, stretch, tensile energy absorption index, and Taber stiff-ness of the paper with 10 kg/ton of chitosan as a wet-end additive showed 22%, 14%, 20%, 59%, 16%, 44%, and 48% improvement, respectively, in comparison to control, (i.e, without its addition). The Cobb60 was also reduced by 45%, showing better resistance to water in comparison to rice straw paper alone. The effects of chitosan added at the wet end on the paper surface were investigated using Fourier transform infrared spectroscopy (FTIR). The use of 10 kg/ton of chitosan at the wet end reduced the color and total suspended solids in the back water of the papermak-ing system by 55% and 51%, respectively. Further enhancement in the surface and strength properties of paper was observed following surface sizing with oxidized starch.
Journal articles
Magazine articles
Fundamental molecular characterization and comparison of the O, D0, and E stage effluents from hardwood pulp bleaching, TAPPI Journal 2019
ABSTRACT: The present study characterized effluents from the O, D0, and E stages using nuclear magnetic reso-nance (NMR) and gel permeation chromatography (GPC) techniques to better understand the chemical nature of the dissolved organics formed from the bleaching of a high-yield hardwood kraft pulp. Understanding the structures and molecular weight distribution of these organics is the first step in developing methods to mitigate these contam-inates in the discharged effluents. The results indicated that the molecular weight distribution (MWD) of the dis-solved organics from oxygen delignification effluent is broader than those from D0 and E stage effluents. In addition, the O stage filtrate contained considerable amounts of lignin and xylan fragments, which showed its efficiency in removing such materials. The effluent from the D0 stage contained a lower amount of high molecular weight frag-ments and a higher amount of low molecular weight fragments versus the O-stage filtrate. Aromatic structures were nearly absent in the D0 stage filtrate, but the degraded organic material, presumably from oxidized lignin, contained olefinic (C=C) and carbonyl (C=O) functional groups. Furthermore, higher molecular weight fragments were detected in the E-stage effluent, presumably due to the extensive solubilization and removal of the oxidized lignin generated from the D0 pulp.
Journal articles
Magazine articles
The sticky behavior of pulp and paper mill biosludge during drying, TAPPI Journal June 2019
ABSTRACT: Pulp and paper mill biosludge becomes sticky after being dried to a certain solids content. As bio-sludge becomes sticky, it agglomerates and adheres to the heat transfer surfaces of the dryer. This undesirable property can lower the dryer efficiency and cause the drying equipment to fail.A systematic study was conducted to examine the sticky behavior of biosludge. The stickiness was evaluated by measuring the adhesive force between a sludge cake and a stainless steel substrate, and the cohesive force between a sludge cake and a sludge substrate. The results show that: i) both adhesive and cohesive forces increase markedly as the solids content increases, reaching a maximum value at about 13% solids, and then decrease steadily at a high-er solids content; ii) cohesive force is stronger than adhesive force, implying that biosludge tends to agglomerate rather than adhere to smooth equipment surfaces; and iii) mixing wood fines or fly ash from a biomass boiler reduc-es the stickiness of the mixture. These findings may help mills improve the thermal efficiency of biosludge dryers and to turn biosludge into a more attractive fuel for burning in biomass boilers.
Journal articles
Magazine articles
Fabrication of cross-linked starch-based nanofibrous mat with optimized diameter, TAPPI JOURNAL June 2019
ABSTRACT: The design and synthesis of natural and synthetic polymer blends have received recent and wide attention. These new biomaterials exhibit progress in properties required in the field of medicine and healthcare. Herein, the aim of present study is to fabricate starch (ST)/polyacrylic acid (PAA) electrospun nanofibrous mat with a smooth and uniform morphology, lowest fiber diameter (below 100 nm) and the highest possible starch content. Starch itself is poor in process-ability, and its electrospinning could be quite a challenging process. To address this, we carried out the response surface methodology (RSM) technique for modelling the electrospinning process. In order to have ST/PAA nanofibers with the finest possible diameter, optimized processing parameters (applied volt-age, nozzle-collector distance and feed rate) obtained from RSM technique were applied. ST/PAA electrospun nano-fibers with an average diameter of 74±13 nm were successfully achieved via the electrospinning method for the first time. The structure, preparation and properties of the nanofibrous structure were discussed. Results indicated that drug loaded ST/PAA blend nanofibrous structure has a great potential to be used in controlled drug release systems.
Journal articles
Magazine articles
Large data set analysis to determine refiner plate total cost of ownership, TAPPI Journal June 2019
ABSTRACT: Efficient process data storage and its subsequent analysis are vital to the profitable operation of a paper mill. An evaluation of refiner plate performance was conducted for an integrated paper mill. Trials with two new plate patterns were compared with the incumbent pattern; the goal was to increase refiner plate life. Plate life increased with both new design patterns, and the mill selected one of the two new choices. However, addi-tional impacts to paper machine performance and mill maintenance costs were not considered in the selection deci-sion. A large data set analysis tool was used to identify unrealized savings of 1.5% with reduced fiber usage (basis weight) on the paper machine’s most prevalent grade. The large data analysis indicated that this unrealized benefit with the alternate plate design was not attainable with the chosen plate design.
Journal articles
Magazine articles
A novel approach for determining the reactivity of dissolving pulp based on the COD method
ABSTRACT: A novel approach for determining the reactivity of dissolving pulp according to the chemical oxygen demand (COD) of water has been discussed. First, a sample of dissolving pulp was subjected to mercerization and xanthation in order to obtain dissolved cellulose fractions. Next, the fractions were digested with a testing solution as applied in COD procedures. Finally, the resulting liquid was rapidly tested by ultraviolet-visible spectrophotometry (UV-Vis). By quantifying the absorbance of Cr3+ at a wavelength of 600 nm, the reactivity of dissolving pulp was indirectly calculated. The results measured by this novel COD method correlated well with the most accepted Fock test results with less than 10% relative difference. Meanwhile, this newly developed COD method required less time-consuming procedures as compared to the Fock test.