Redispersion and structural change evaluation of dried microfibrillated cellulose

Silva, Luiz Eduardo; Santos, Allan de Amorim dos; Torres, Lennard; McCaffrey, Zach; Klamczynski, Artur; Glenn, Greggory; Neto, Alfredo Rodrigues de Sena; Wood, Delilah F.; Williams, Tina; Orts, William J.; Damásio, Renato Augusto Pereira; Tonoli, Gustavo Henrique Denzin

doi:10.1016/j.carbpol.2020.117165

Cited by 52 publications

(16 citation statements)

References 35 publications

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“…[42] Upon drying, cellulose undergoes partly irreversible reorganization like aggregation or surface passivation to find the energetically most favorable state, a process named hornification. [54] As a consequence, NC dewatering and drying processes pose several problems. The first is due to the cost of removing the tightly bound water.…”

Section: The Complex Role Of Hydroxyls: the Love-hate Relationship Between Nanocellulose And Watermentioning

confidence: 99%

Nanocellulose and Its Interface: On the Road to the Design of Emerging Materials

Bettotti

Scarpa

2021

Adv Materials Inter

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The interest in the hierarchical structure, the multi-scale organization, and the properties of cellulose has long been the prerogative of botanists and plant physiologists. The last decade has witnessed the potential of a top-down approach to take apart cellulose-based raw materials into their micro-and nano-sized building blocks and to use them to design and fabricate functional materials and devices with new and, in some cases, outstanding properties. At present, cellulose is not only one of the main constituents of the plant and bacterial kingdom, it is also an important component of materials and manufactured goods, such as paper, textiles, or food additives. Depending on the extent of the scale down process, the fragments have variable size and in this review are collectively indicated as nanocellulose (NC). Although the interfacial properties of NC are always mentioned and recognized to contribute significantly to NC behavior, there is still room for reviewing the several recent reports highlighting the role of the interaction at the interface. In this scenario, the interface driven performances of some advanced NC-based materials are gaining in importance. This review aims at providing an overview of the most advanced of them, such as the Pickering emulsions, the supercapacitors, the drug crystallizing capsules, the nanowood.In nature, cellulose is synthesized by plants and also by some bacterial strains which can polymerize the glucose residues into linear β − 1, 4 −glucan chains. Once extracellularly secreted, the chains assemble, crystallize (the degree of crystallinity is up to 90%), and form nanostructures called bacterial nanocellulose (BNC) which in turn assemble forming microfibrils. Different from plant tissues where cellulose is embedded in a heterogeneous macrostructure, bacterial secretions are made of pure cellulose and are considered an excellent source of NC. [2] However, due to the large availability of cellulose from wood or other lowcost vegetable sources such as agriculture wastes, plant cellulose is the most common material for NC production. Several strategies for the preparation of NC have been reported. [3] A popular production route uses a pretreatment to introduce negative charges by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mediated oxidation followed by a mechanical disintegration. [4] The behavior of NC has been largely studied, and it is well assessed that when NC colloidal suspensions are dried, they form flexible and transparent films with multifunctional properties. [5] These properties, first of all, depend on the degree of fibrillation of the colloidal NC. [6] Conversely, in aqueous solutions, NC Nanocellulose has several unique properties that render it a versatile mate rial with possible uses in a broad spectrum of applications. Nanocellulose is proved to form stable colloidal suspensions with interesting rheological properties, assemble in soft hydrogels of tunable porosity, compact dried films. Suggested or already current applications of these systems are in the f...

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Section: The Complex Role Of Hydroxyls: the Love-hate Relationship Between Nanocellulose And Watermentioning

confidence: 99%

Nanocellulose and Its Interface: On the Road to the Design of Emerging Materials

Bettotti

Scarpa

2021

Adv Materials Inter

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“…Studies related to the drying of fiber have already been reported (Zimmermann et al 2016;Silva et al 2021). However, there is still a lack of information about the microfibrillation process of unbleached Eucalyptus kraft pulp, whereas more data could help optimize the fibrillation process and facilitate the scaling up of MFC production.…”

Section: )mentioning

confidence: 99%

Optimizing cellulose microfibrillation with NaOH pretreatments for unbleached Eucalyptus pulp

et al. 2021

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This study aimed to assess the effect of drying unbleached Eucalyptus cellulose fibers after the application of pretreatments in order to optimize the microfibrillation process, as well as to evaluate the efficiency of NaOH pretreatments in reducing energy consumption for production of microfibrillated cellulose (MFC). Pretreatments with 0 wt% (untreated), 5 wt% and 10 wt% NaOH were evaluated. The length and width of the fibers pretreated with NaOH decreased significantly, mainly with hasher pretreatments.The removal of hemicellulose from the fiber cell wall was an important factor concerning the degree of fibrillation of the fibers. Pretreating fibers with 5 wt% NaOH for 2 h increased the water retention value (WRV), in addition to presenting the lowest energy consumption for fibrillation, promoting energy savings of up to 48%. Pulps that were not dried after the NaOH pretreatments incurred in easier microfibrillation and lower energy consumption when comparing to the dried pulp, which shows the negative impact of drying on the fibers to obtain the MFC.

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“…While the resolution of TEM can analyse bre width down to a few nanometres, SEM is only capable of analysing bre width greater than 100 nm (Kangas et al 2014). In addition, the three-dimensional structure and bulk morphology of the sample is disrupted during the drying step required for sample preparation (Peng et al 2012;Silva et al 2021). Meanwhile, indirect characterisation involves measuring a derived property of the nano bre system, such as the bre-light interaction (DLS, UV-vis transmittance), bre-solvent interaction (rheology, sedimentation behaviour, water retention capacity), bre-bre interaction (nanopaper mechanical properties), or speci c surface area (SANS, SAXS, DSC, BET adsorption, solvent relaxation NMR, conductimetric titration).…”

Section: Importance Of Cellulose Nano Bre (Cnf) Morphologymentioning

confidence: 99%

Assessing Cellulose Micro/Nanofibre Morphology Using a High Throughput Fibre Analysis Device to Predict Nanopaper Performance

Pennells¹,

Heuberger²,

Chaleat³

et al. 2021

Preprint

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Characterising cellulose nanofibre (CNF) morphology has been identified as a grand challenge for the nanocellulose research field. Direct techniques for CNF morphology characterisation exhibit various difficulties related to the material network structure and equipment cost, while indirect techniques that investigate fibre-light interaction, fibre-solvent interaction, fibre-fibre interaction, or specific fibre surface area involve relatively facile methods but may be more unreliable. Nanopaper mechanical testing is a prevalent metric for assessing fibre-fibre interaction, but is an off-line, time-consuming, and destructive methodology. In this study, an optical fibre morphology analyser (MorFi, TechPap) was employed as an on-line, high throughput, fast turnaround tool to assess micro/nanofibre pulp morphology and predict the properties of nanopaper material. Correlation analysis identified fibre content and fibre kink properties as most correlated with nanopaper strength and toughness, while fibre width and coarseness were most inversely correlated with nanopaper performance. Principal component analysis (PCA) was employed to visualise interdependent morphological and mechanical data. Subsequently, two data driven statistical models - multiple linear regression (MLR) and machine learning based support vector regression (SVR) - were established to predict nanopaper properties from fibre morphology data, with SVR generating a more accurate prediction across all nanopaper properties (NRMSE = 0.13-0.33) compared to the MLR model (NRMSE = 0.33-0.51). This study highlights that statistical methods are useful to disentangle and visualise interdependent morphological data from an on-line fibre analysis device, while regression models are also capable of predicting paper mechanical properties from CNF samples even though these devices do not operate at nanoscale resolution.

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Redispersion and structural change evaluation of dried microfibrillated cellulose

Cited by 52 publications

References 35 publications

Nanocellulose and Its Interface: On the Road to the Design of Emerging Materials

Nanocellulose and Its Interface: On the Road to the Design of Emerging Materials

Optimizing cellulose microfibrillation with NaOH pretreatments for unbleached Eucalyptus pulp

Assessing Cellulose Micro/Nanofibre Morphology Using a High Throughput Fibre Analysis Device to Predict Nanopaper Performance

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