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Understanding the pulping and bleaching performances of eucalyptus woods affected by physiological disturbance, TAPPI Journal November 2018
Understanding the pulping and bleaching performances of eucalyptus woods affected by physiological disturbance, TAPPI Journal November 2018
Journal articles
Magazine articles
Editorial: Looking back and looking forward: Paper physics and the paper industry, TAPPI Journal October 2018
Editorial: Looking back and looking forward: Paper physics and the paper industry, TAPPI Journal October 2018
Journal articles
Magazine articles
A review of green liquor scale formation, TAPPI Journal October 2018
A review of green liquor scale formation, TAPPI Journal October 2018
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Magazine articles
A Theory for the Tensile Strength of Paper, TAPPI Journal October 2018
A Theory for the Tensile Strength of Paper, TAPPI Journal October 2018
Journal articles
Magazine articles
Prehydrolysis kraft pulping of jute cutting and caddis mixture for rayon production
ABSTRACT: Jute cutting, jute caddis, and cutting-caddis mixtures were prehydrolyzed by varying time and temperature to get about 90% prehydrolyzed yield. At the conditions of 170°C for 60 min of prehydrolysis, the yield for 100% jute cutting was 76.3%, while the same for jute caddis was only 67.9%. But with prehydrolysis at 150°C for 60 min, the yield was 90% for jute cutting, where 49.94% of original pentosan was dissolved and prehydrolysis of jute caddis at 140°C in 60 min yielded 86.4% solid residue. Jute cutting-caddis mixed prehydrolysis was done at 140°C for 30 min and yielded 92% solid residue for 50:50 cutting-caddis mixtures, where pentosan dissolution was only 29%. Prehydrolyzed jute cutting, jute caddis, and cutting-caddis mixtures were subsequently kraft cooked. Pulp yield was only 40.9% for 100% jute cutting prehydrolyzed at 170°C for 60 min, which was 10.9% lower than the prehydrolysis at 140°C. For jute cutting-caddis mixed prehydrolysis at 140°C for 45 min followed by kraft cooking, pulp yield decreased by 3.3% from the 100% cutting to 50% caddis in the mixture, but 75% caddis in the mixture decreased pulp yield by 6.7%. The kappa number 50:50 cutting-caddis mixture was only 11.3. Pulp bleachability improved with increasing jute cutting proportion in the cutting-caddis mixture pulp.
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Sources, collection, and handling of noncondensible gases in modern kraft pulp mills
ABSTRACT: This work describes and discusses sources of noncondensible gases (NCG) in modern kraft pulp mills and modern NCG collection from process units where odor emissions can occur if these gases are released to the surroundings. A mill-wide overview of NCG sources and collection in modern pulp mills is provided. Using modern practices, malodorous gases can be collected to the extent that a pulp mill is essentially odor free. The key to limiting complaint-causing odors is prevention of these emissions during process disturbances, equipment malfunctions, operator errors, and other unforeseen occurrences.
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Research needs for nanocellulose commercialization and applications
INTRODUCTION: This short review deals with some applications and research needs for nanocellulosic (NC) materials; primarily cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial cellulose (BC). Whereas CNC and BC materials are fairly homogenous, CNF materials represent a wide sector of different materials, often with a high heterogeneity. This is due to different pretreatment methods (mechanical, chemical, enzymatic), woodbased or agricultural-based materials, delignification and bleaching procedures, etc. The purpose of this comprehensive review is not to discuss the various production methods, for which the reader may consult with a selected number of reviews [1-6]; thus, the focus is on practical applications. Practical applications and potential markets were also discussed some years ago by other investigators [7-8]. Upscaling and choice of pretreatment methods, as well as economic considerations and different business models, have also been discussed, along with: œ Toxicity and environmental issues [9-10] œ The complex characterization of cellulose nanomaterials [4] The reader should also be aware of new contenders to the three classic groups of cellulosic nanomaterials, which are already in a commercial phase. These include cellulose filaments [11-12] and materials from mechanical grinding processes [13], and these materials may be nanostructures or not, depending on our classification. Finally, as indicated by the editorial on p. 275, scientists are currently taking a deep dive into the fundamental features of nanocellulosic materials [14-15].
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Effects of preincubation on the gelatinization of cassava and corn starch suspensions containing sodium hydroxide as a main component of corrugating adhesives
ABSTRACT: Effects of the preincubation temperature and the caustic-ratio, the molar ratio of sodium hydroxide to starch glucose residue, on the gelatinization of cassava starch and corn starch suspensions were studied using differential scanning calorimetry in view of utilization for corrugating adhesives. The gelatinization temperature and enthalpy change of cassava starch suspensions after the preincubation at 30°C decreased as the caustic-ratio increased, similar to those of corn starch ones: The gelatinization starting temperature (Ts) decreased considerably more than the peak temperature and the conclusion temperature (Tc). Although Ts lowered and the width of gelatinization temperature expanded, compared with those of corn starch suspensions, the two starch suspensions with the same half gelatinization transition temperature showed similar gelatinization characteristics of almost the same Ts and Tc. During 1 h-preincubations at 30°C•50°C, the starch granules with Ts that were lowered considerably below each preincubation temperature by sodium hydroxide showed limited gelatinization. The gelatinization transition did not rapidly spread over the whole suspension, but progressed stepwise in response to the increase of the causticratio and the rise of the preincubation temperature. In a prolonged preincubation at a constant temperature, Ts gradually rose at higher caustic-ratios in which stepwise gelatinization commenced. Although the starch gelatinization was irreversible and not in a stable equilibrium state for a long time, we concluded that such stepwise gelatinization progress controlled the practical preparation and use of corrugating adhesives.
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Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer, TAPPI Journal November 2019
ABSTRACT: The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compo-sitions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.
Journal articles
Magazine articles
Editorial: Diverse content characterizes PaperCon 2019, TAPPI Journal November 2019
ABSTRACT: PaperCon 2019 was held from May 5-8 in Indianapolis, IN. Many of us visiting Indianapolis had little or no perception of the area beyond, of course, race cars and good sports teams. We also found a lovely, walkable downtown with a myriad of restaurants, parks, historic sites, and state government. As with the diverse offerings of PaperCon 2019’s host city of Indianapolis, the conference technical program was exceptionally broad this year. In this special issue of TAPPI Journal, we share both the breadth and quality of the content presented at PaperCon 2019 through peer-reviewed papers from the conference, as described below.