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Magazine articles
The r & t system: everyone is responsible for innovation, TAPPI JOURNAL, September 2000, Vol. 83(9)
The r & t system: everyone is responsible for innovation, TAPPI JOURNAL, September 2000, Vol. 83(9)
Journal articles
Effect of softwood kraft on a mechanical-chemical mixture sheet, TAPPI JOURNAL, October 2000, Vol. 83(10)
Effect of softwood kraft on a mechanical-chemical mixture sheet, TAPPI JOURNAL, October 2000, Vol. 83(10)
Magazine articles
The role of science in setting the environmental agenda, TAPPI JOURNAL, September 2000, Vol. 83(9)
The role of science in setting the environmental agenda, TAPPI JOURNAL, September 2000, Vol. 83(9)
Journal articles
Developments in activity generation on fourdriniers, TAPPI JOURNAL, October 2000, Vol. 83(10)
Developments in activity generation on fourdriniers, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
Barium sulfate scale in the fiberline, TAPPI JOURNAL, October 2000, Vol. 83(10)
Barium sulfate scale in the fiberline, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
The use of a flocculation sensor as a predictive tool for paper machine retention program performance, TAPPI JOURNAL, October 2000, Vol. 83(10)
The use of a flocculation sensor as a predictive tool for paper machine retention program performance, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
Transition metal complexes: a new class of laccase mediators for pulp bleaching, TAPPI JOURNAL, October 2000, Vol. 83(10)
Transition metal complexes: a new class of laccase mediators for pulp bleaching, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
The laboratory twin-former part 1: design and performance, TAPPI JOURNAL, October 2000, Vol. 83(10)
The laboratory twin-former part 1: design and performance, TAPPI JOURNAL, October 2000, Vol. 83(10)
Journal articles
A virtuous circle, TAPPI JOURNAL, December 2000, Vol. 83(12)
A virtuous circle, TAPPI JOURNAL, December 2000, Vol. 83(12)
Journal articles
Paper strength factors in systems with nanofibrillated cellulose, cationic starch, colloidal silica, cationic acrylamide copolymer, and hydrodynamic shear, TAPPI Journal May 2025
ABSTRACT: Laboratory paper sheets were formed by first pretreating nanofibrillated cellulose (NFC) with cationic starch at the 5% level by mass. The treated NFC was then added to stock prepared from 100% recycled copy paper. The combined furnish was next optionally treated with a cationic retention aid (cPAM, 0.1%) and then colloidal silica (0.1% or 0.2%). Vacuum dewatering, fine-particle retention, and several paper properties were studied as a function of the colloidal silica level (zero, 1%, and 2%) and at different levels of shear stress applied just before forming the sheets. Dewatering and strength results were generally more favorable when using a medium charge cationic starch (~ 0.03 degree of substitution, DS) to pretreat the NFC rather than a high charge density cationic starch (~ 0.2 DS). In each case, the dewatering was further enhanced by subsequent treatments by cPAM (0.1% on whole furnish solids) and then even more with the final addition of colloidal silica (0.1% and 0.2% levels compared). However, the colloidal silica additions progressively hurt the tensile strength of the paper, especially in the case of the high charge cationic starch and at the higher level of colloidal silica. Though the dewatering performance was favorable, in such cases, the paper strength was not improved compared to paper made without any NFC. The fact that the systems involving cPAM treatment, and especially those involving both cPAM and colloidal silica, tended to reduce the resulting paper’s tensile strength supports a mechanism in which the additives result in the clustering of the NFC, possibly in multiparticle bunches. Evidence suggests that such bunches of clustered NFC particles, which are difficult to redisperse even at levels of hydrodynamic shear present in high-speed paper machine systems, are resistant to full integration into the sheet structure as the paper is being formed.