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Characterization of the redispersibility of cellulose nanocrystals by particle size analysis using dynamic light scattering, TAPPI Journal April 2019
ABSTRACT: Cellulose nanocrystals (CNCs), which are derived from the most abundant and inexhaustible natural polymer, cellulose, have received significant interest owing to their mechanical, optical, chemical, and rheological properties. In order to transport CNC products conveniently and efficiently, they are ideally dried and stored as pow-ders using freeze-drying or spray-drying technologies. The redispersibility of CNC powders is quite important for their end use; hence, a convenient method is required to characterize the redispersibility of CNC powders. In this paper, the possibility of characterizing the redispersibility of CNC powders by particle size analysis using dynamic light scattering (DLS) was investigated by comparing the results from transmission electron microscopy (TEM) and DLS. The particle size obtained with DLS approximately matched that obtained with TEM. Compared with TEM, DLS is a quick and convenient method to measure the particle size distribution of CNCs in water. Two kinds of dispersing methods, sonication and high-speed shearing, and two kinds of CNCs prepared by different methods, sulfuric acid hydrolysis and the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) oxidization method, were used to study the redis-persibility of CNCs. Sonication was more efficient than the high-speed shearing method for nanoscale dispersion of CNC powders in water. CNCs prepared by sulfuric acid hydrolysis could be more easily redispersed in water than those prepared by TEMPO oxidation.
Journal articles
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Priorities for development of standard test methods to support the commercialization of cellulose nanomaterials, TAPPI Journal April 2019
ABSTRACT: With the growing number of producers and users of cellulose nanomaterials (CNMs), there is an increasing need to develop standard test methods to control production and quality of CNMs. In 2014, a Task Group was formed within the ISO Technical Committee 6 Paper, board and pulps to begin addressing the need for standards. This Task Group, TG 1, was tasked with reviewing existing standards and identifying the need for additional standards to characterize CNMs.In March 2018, TG 1 launched a survey to ask CNM producers around the world about the importance of having standard procedures to measure and quantify a variety of CNM properties, both physical and chemical. Producers were asked to identify the type(s) of CNM they produced and their scale of production, and to rank the properties for which they felt standard test methods were most important. In this paper, we summarize the survey responses and identify those properties of highest interest for producers of both cellulose nanocrystals (CNCs) and cellulose nano- and microfibril-based materials (CNFs/CMFs). Properties of importance can be divided into three broad groups: i) a standard has either been developed or is under develop-ment, ii) a currently used standard could be adapted for use with CNMs, or iii) no standard is currently available and further R&D and consultation with industry is needed before a suitable and well-validated standard can be developed. The paper also examines the challenges of developing new standard methods for some of the key properties—as well as the feasibility and limitations of adapting exiting standards—to CNMs.
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Wet-end addition of nanofibrillated cellulose pretreated with cationic starch to achieve paper strength with less refining and higher bulk, TAPPI JOURNAL July 2018
Wet-end addition of nanofibrillated cellulose pretreated with cationic starch to achieve paper strength with less refining and higher bulk, TAPPI JOURNAL July 2018
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An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling, TAPPI JOURNAL March 2018
An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling, TAPPI JOURNAL March 2018
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TAPPI Journal Summaries, Paper360º July/August 2019
TAPPI Journal Summaries, Paper360º July/August 2019
Journal articles
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A novel predictive method for filler coflocculation with cellulose microfibrils, TAPPI Journal November 2019
ABSTRACT: Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and benonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.
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TAPPI Nano 2019: Focus on New Markets, Paper360º September/October 2019
TAPPI Nano 2019: Focus on New Markets, Paper360º September/October 2019
Journal articles
Magazine articles
Degradation of 2,4-dichlorophenol by melamine amine cellulos
Degradation of 2,4-dichlorophenol by melamine amine cellulose- immobilized lacasses, TAPPI JOURNAL October 2017
Journal articles
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Novel CaCO3-polymer nanocomposite fillers for the improvemen
Novel CaCO3-polymer nanocomposite fillers for the improvement of bagasse-based papers, November 2016 TAPPI JOURNAL