Size reversion in alkaline papermaking

Author: gcpp

August undefined, 2024

WebbIt is a reactive size as it forms covalent bonds with cellulose at neutral or alkaline pH during the papermaking system (Lee and Luner, 2005; Song et al., 2012). WebbThe specific mechanism of AKD reversion is unclear. However, several processes have been suggested to explain the observed reversion. The most likely mechanisms from the literature are' Hydrolysis of AKD to form the less efficient sizing ketone, 2 Interaction of AKD with additives in the papermaking fixmish, 3,4,s,6,7

Size reversion in alkaline papermaking. Article Information J …

WebbSize reversion in alkaline papermaking, TAPPI JOURNAL, August 1993, Vol. 76 (8) TAPPI conference proceedings and presentations, technical papers, and publication articles … Webbsystems is unsuitable in the alkaline environment. Instead, synthetic siz- ing agents such as alkyl ketene dimer (AKD) and alkenyl succinic anhy- dride (ASA) are the choice. AKD … iaee women\\u0027s leadership summit 2023

Effects of AKD Sizing on the Morphology and Pore Distribution

WebbSize reversion is the loss of size response with time after the paper has been made. The work reported here suggests that size reversion increases at higher pH. Both authors are at Nalco Chemical Co. "Pilot Plant Dynamics and AKD Sizing," by H.W. Kropholler and A. Mendes de Sousa. WebbHydrophobes in Surface Treatment Formulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111 Retention ... WebbArticle “Size reversion in alkaline papermaking.” Detailed information of the J-GLOBAL is a service based on the concept of Linking, Expanding, and Sparking, linking science and … iaee women\u0027s leadership foundation

Autoxidation: Predominant mechanism of size reversion

Instituteof PaperScien e and Technology Atlanta, Georgia

WebbIncreasing paper drying temperature in the 180 to 2700F range reduced initial sizing for papers filled with precipitated calcium carbonate pigment. The negative effect of … WebbLater in the century they made a size from flour starch which was added to the paper pulp in the tub or to the finished sheet after forming. In the mid 8th century papermaking was introduced to the Arab world ... After the emulsion settled, the excess alkaline liquors were skimmed off the top and discarded. Some papermakers let the size sit ... iaee young professionalsWebbSize reversion over days and weeks was also a problem depending on the PCC used, with larger PCC particles causing fewer problems but giving lower opacity. ... In alkaline papermaking, one will get improved sizing by using higher levels of high DS cationic starch. molting experiment

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Size reversion in alkaline papermaking

Webb5 juni 2013 · over the years the most important sizes used are the Alkyl. Ketene Dimers (AKD) and the Alkenyl ... restricted to neutral/alkaline papermaking, although. ASA may be used at slightly acidic pH ... R. and Rende, D. (1993): Size reversion in alkaline papermaking, Tappi J. 76(8), 117-120. Petander, L., Ahlskog, T. and Juppo, A. J. (1998 ... Webb1 okt. 2008 · ASAs are generally synthesized by reacting maleic anhydride with alkenes having chain length in the range of about 14e20 carbons via Alder-ene reaction [27,28], …

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WebbChanges in wet end of alkaline papermaking affect the size development as well as sizing loss. These changes include pH, alkalinity and type of filler used. Precipitated and … Webb27 mars 2014 · Even though sizing with so called reactive sizing agents like alkenyl succinic anhydride (ASA) and alkyl ketene dimere (AKD) was implemented in the paper industry during the change to neutral and...

Webb1 juli 2012 · Paper industries are shifting from neutral to alkaline sizing process. Alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA) are two main sizing agents … Webb31 mars 2024 · Paper sizing was found to be achieved by bound AKD. This means that an even lower additional level of AKD would be sufficient to ensure good paper sizing provided that it forms a chemical bond with furnish. This result is believed to be important in solving some problems associated with AKD sizing.

WebbDarroch, all of Westvaco. Size reversion is the loss of water repellency, weeks or months after the paper is manufactured. It is aggravated by high drying temperature and small filler particles (below about 1.9 microns). "Analysis of Alkyl Ketene Dimer (AKD) by Potentiometric Titration," by S. Nyarku and B.B. Sitholé. This method was WebbChanges in wet end of alkaline papermaking affect the size development as well as sizing loss. These changes include pH, alkalinity and type of filler used. Precipitated and ground varieties of carbonate fillers and the alkalinity associated with · them are believed to be the causes for the gradual sizing loss in alkaline papers due the accelerated hydrolysis …

Webb1 sep. 2000 · In order to make the mechanism of size reversion for alkenyl succinic anhydride (ASA)-sized papers clear, an ASA-sized and CaCO3-filled commercial paper …

WebbSize reversion in e Pap Robert W. Novak and Dominic S. Rende ABSTRACT ciency is the relationship between the Size response is hebped in uhdinepupmking by response and … molting feetWebb27 mars 2014 · In order to make the mechanism of size reversion for alkenyl succinic anhydride (ASA)-sized papers clear, an ASA-sized and CaCO3-filled commercial paper … molting elephant sealWebb7 juni 2008 · papermaking systems has been transformed to neutral-alkaline papermaking conditions, and in parallel, the use of acidic alum-rosin sizing has decreased.2 Under neutral-alkaline papermaking conditions, alum tends to be converted to neutral aluminum ﬂoc, Al(OH) 3, which is not an effective species for retaining rosin particle on ﬁber … iae f040 2015 09Webbalkaline systems are generally re- served for neutral rosin. The Dumas description carefully outlines the step- by-step sequence of events in the alkaline sizing process and describes its greater fragility or sensitivity to other papermaking environmental factors. The rosin-alum system is different because the size precipitate iae foot trimming kitWebb1 nov. 2016 · Alkyl ketene dimer (AKD) is the reactive synthetic sizing agent that is used in alkaline or neutral papermaking conditions to provide certain level of hydrophobicity to the paper and board. The sizing mechanism of AKD involves its reaction with the hydroxyl groups on cellulose. molting foxWebb13 apr. 2024 · The fabrication of pH-sensitive lignin-based materials has received considerable attention in various fields, such as biomass refining, pharmaceuticals, and detecting techniques. However, the pH-sensitive mechanism of these materials is usually depending on the hydroxyl or carboxyl content in the lignin structure, which hinders the … molting feathersWebbsizing using rosin size due to its better hydrophobicity and lesser size reversion, as well as better durability of paper produced (Lee and Luner, 2005, Song et al., 2012). Conversion … iae fortex