Jump to content

User:*LauRy893/sandbox: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
*LauRy893 (talk | contribs)
40 edits
No edit summary
*LauRy893 (talk | contribs)
40 edits
No edit summary
Tag: Possible self promotion in userspace
Line 1: Line 1:
[[File:Nanocellulose.JPG|right|thumb|Nanocellulose]]
{{#babel:it}}
'''Nanocellulose''' is a term referring to nano-structured cellulose. This may be either '''cellulose nanocrystal''' (CNC or NCC), '''cellulose nanofibers''' (CNF) also called '''microfibrillated cellulose''' (MFC), or '''bacterial nanocellulose''', which refers to nano-structured cellulose produced by bacteria.
{{#babel:en-3}}

<!-- EDIT BELOW THIS LINE -->
CNF is a material composed of [[nanotechnology|nanosized]] [[cellulose]] fibrils with a high aspect ratio (length to width ratio). Typical fibril widths are 5–20 [[nanometers]] with a wide range of lengths, typically several [[micrometers]]. It is pseudo-plastic and exhibits [[thixotropy]], the property of certain [[gel]]s or [[fluid]]s that are thick (viscous) under normal conditions, but become less viscous when shaken or agitated. When the shearing forces are removed the gel regains much of its original state. The fibrils are isolated from any cellulose containing source including wood-based fibers ([[Pulp (paper)|pulp fibers]]) through high-pressure, high temperature and high velocity impact [[Homogenization (chemistry)|homogenization]], grinding or microfluidization (see manufacture below).
'''Hello''', my name is Laura. I live in [[Italy]]. I like [[music]]. I play the [[piano]] and the [[clarinet]].

Nanocellulose can also be obtained from native fibers by an acid hydrolysis, giving rise to highly crystalline and rigid nanoparticles which are shorter (100s to 1000 nanometers) than the nanofibrils obtained through homogenization, microfluiodization or grinding routes. The resulting material is known as '''cellulose nanocrystal''' (CNC).<ref>{{cite journal|vauthors=Peng BL, Dhar N, Liu HL, Tam KC|year=2011|title=Chemistry and applications of nanocrystalline cellulose and its derivatives: A nanotechnology perspective|journal=The Canadian Journal of Chemical Engineering|volume=89|issue=5|pages=1191–1206|url=http://www.arboranano.ca/pdfs/Chemistry%20and%20applications%20of%20nanocrystalline%20cellulose%20and%20its%20derivatives%20A%20nanotechnology%20perspective-2011.pdf|doi=10.1002/cjce.20554|access-date=2012-08-28|archive-url=https://web.archive.org/web/20161024021059/http://www.arboranano.ca/pdfs/Chemistry%20and%20applications%20of%20nanocrystalline%20cellulose%20and%20its%20derivatives%20A%20nanotechnology%20perspective-2011.pdf|archive-date=2016-10-24|dead-url=yes|df=}}</ref>

==History and terminology==
The terminology [[microfibrillated]]/nanocellulose or (MFC) was first used by Turbak, Snyder and Sandberg in the late 1970s at the ITT [[Rayonier]] labs in [[Whippany, New Jersey]], USA to describe a product prepared as a gel type material by passing wood pulp through a Gaulin type milk homogenizer at high temperatures and high pressures followed by ejection impact against a hard surface.{{citation needed|date=March 2017}}

The terminology first appeared publicly in the early 1980s when a number of patents and publications were issued to ITT Rayonier on a new nanocellulose composition of matter.<ref name="Turbak1983"/> In later work Herrick{{who|date=March 2017}} at Rayonier also published work on making a dry powder form of the gel.<ref name="Herrick1983"/> Rayonier has been one of the world's premier producers of purified pulps interested in creating new uses and new markets for pulps and not to compete with new customers. Thus, as the patents issued,<ref name="Turbak, A, F., Snyder, F.W. and Sandberg, K.R."/> Rayonier gave free license to whoever wanted to pursue this new use for cellulose. Rayonier, as a company, never pursued scale-up. Rather, Turbak et al. pursued 1) finding new uses for the MFC/nanocellulose. These included using MFC as a thickener and binder in foods, cosmetics, paper formation, textiles, nonwovens, etc. and 2) evaluate swelling and other techniques for lowering the energy requirements for MFC/Nanocellulose production.<ref name = "Turbak, A.F.">Turbak, A.F., Snyder, F.W. and Sandberg, K.R. (1984) "Microfibrillated Cellulose—A New Composition of Commercial Significance," 1984 Nonwovens Symposium, Myrtle Beach, SC, Apr. 16–19. TAPPI Press, Atlanta, GA. pp 115–124.</ref> After ITT closed the Rayonier Whippany Labs in 1983–84, Herric worked on making a dry powder form of MFC at the Rayonier labs in [[Shelton, Washington]], USA<ref name="Herrick1983"/>

In the mid 1990s the group of Taniguchi and co-workers and later Yano and co-workers pursued the effort in Japan.<ref name="Berglund2005"/> and a host of major companies, see numerous U.S. patents issued to P&G, J&J, 3M, McNeil, etc. using U.S. patent search under inventor name Turbak search base.

==Manufacture==

Nanocellulose, which is also called cellulose nanofibers (CNF), microfibrillated cellulose (MFC) or cellulose nanocrystal (CNC), can be prepared from any cellulose source material, but [[woodpulp]] is normally used.

The nanocellulose fibrils may be isolated from the wood-based fibers using mechanical methods which expose the pulp to high shear forces, ripping the larger wood-fibres apart into nanofibers. For this purpose, high-pressure homogenizers, ultrasonic homogenizers,<ref>{{cite web|url=http://www.hielscher.com/ultrasonic-production-of-nano-structured-cellulose.htm|title=Ultrasonic Production of Nano-Structured Cellulose|publisher=hielscher.com|accessdate=27 January 2015}}</ref>{{better source|date=March 2017}} grinders or microfluidizers can be used.{{citation needed|date=March 2017}} The homogenizers are used to delaminate the cell walls of the fibers and liberate the nanosized fibrils. This process consumes very large amounts of energy and values over 30 MWh/[[tonne]] are not uncommon.{{citation needed|date=March 2017}}

To address this problem, sometimes enzymatic/mechanical pre-treatments<ref name="Paakko2007"/> and introduction of charged groups for example through carboxymethylation<ref name="Wagberg2008"/> or [[TEMPO|TEMPO-mediated oxidation]] are used.<ref>{{cite web|url=http://mwp.org/2015-akira-isogai-tsuguyuki-saito-japan-and-yoshiharu-nishiyama-france/|title=Marcus Wallenberg Prize: 2015 – Akira Isogai, Tsuguyuki Saito, Japan, and Yoshiharu Nishiyama, France|publisher=http://mwp.org/|accessdate=23 January 2018}}</ref> These pre-treatments can decrease energy consumption below 1 MWh/tonne.<ref name="Lindstrom2009"/> Recently, a new method "Nitro-oxidation" has been developed to prepare carboxycellulose nanofibers directly from raw plant biomass. Due to less number of processing steps to extract nanocellulose, Nitro-oxidation method has found to be a cost-effective, less-chemically oriented and efficient method to extract carboxycellulose nanofibers.<ref name="Sharma2017b">{{cite journal|last=Sharma|first=P.R.|author2=Joshi,R.||author3=Sunil K.,S.||author4=Benjamin S.,H.| year=2017 | title=A Simple Approach to Prepare Carboxycellulose Nanofibers from Untreated Biomass|journal=Biomacromolecules|volume=18|pages=2333–2342|doi=10.1007/s10570-0|issue=8}}</ref> <ref name="Sharma2018c">{{cite journal|last=Sharma|first=P.R.|author2=Zheng,B.||author3=Sunil K.,S.||author4=Zhan C.||author5=Wang R.||author6=Bhatia S.,R.||author7=Benjamin S.,H.| year=2018 | title=High Aspect Ratio Carboxycellulose Nanofibers Prepared by Nitro-Oxidation Method and Their Nanopaper Properties|journal=ACS Appl. Nano Mater.|volume=1|pages=3969-3980|doi=10.1021/acsanm.8b00744|issue=8}}</ref> Functionalized nanofibers obtained using nitro-oxidation has found excellent substrate to remove heavy metal ions impurities such as lead<ref name="Sharma2018a">{{cite journal|last=Sharma|first=P.R.|author2=Chattopadhyay,A.||author3=Sunil K., S.||author4=Lihong G.,S.||author5=Benjamin S.,H.| year=2018 | title=Lead removal from water using carboxycellulose nanofibers prepared by nitro-oxidation method|journal=Cellulose|volume=25|pages=1961–1973|doi=10.1007/s10570-018-1659-9) |issue=3}}</ref> cadmium<ref name="Sharma2018b">{{cite journal|last=Sharma|first=P.R.|author2=Chattopadhyay, A.||author3=Sunil K., S.||author4=Lihong G., S.||author5=Nasim A.||author6=Darren M.||author7=Benjamin S., H.| year=2018 | title=Nanocellulose from Spinifex as an Effective Adsorbent to Remove Cadmium(II) from Water|journal=ACS Sustainable Chem. Eng.|volume=6|pages=3279–3290|doi=10.1021/acssuschemeng.7b03473) |issue=3}}</ref> uranium<ref name="Sharma2017a">{{cite journal|last=Sharma|first=P.R.|author2=Chattopadhyay, A.||author3=Sunil K., S.||author4=Benjamin S., H.| year=2017 | title=Efficient Removal of UO22+ from Water Using Carboxycellulose Nanofibers Prepared by the Nitro-Oxidation Method|journal=Industrial & Engineering Chemistry Research|volume=56|pages=13885-13893|doi=10.1021/acs.iecr.7b03659) |issue=46}}</ref>


Cellulose nanowhiskers are rodlike highly crystalline particles (relative crystallinity index above 75%) with a rectangular cross section. They are formed by the acid hydrolysis of native cellulose fibers commonly using sulfuric or hydrochloric acid. Amorphous sections of native cellulose are hydrolysed and after careful timing, crystalline sections can be retrieved from the acid solution by centrifugation and washing. Their dimensions depend on the native cellulose source material, and hydrolysis time and temperature.{{citation needed|date=March 2017}}
Spherical shape carboxycellulose nanoparticles prepared by nitric acid-phosphoric acid treatment has found to stable in dispersion in its non-ionic form.<ref name="Sharma2017">{{cite journal|last=Sharma|first=P.R.|author2=Verma, A.J.| year=2013 | title=Functional nanoparticles obtained from cellulose: engineering the shape and size of 6-carboxycellulose|journal=Chemical Communications|volume=49|pages=13885-13893|doi=10.1039/C3CC44551H)|issue=|}}</ref>
In April 2013 breakthroughs{{clarify|date=March 2017}} in nanocellulose production were announced at an American Chemical Society conference.<ref>{{cite web|url=http://www.newswise.com/articles/engineering-algae-to-make-the-wonder-material-nanocellulose-for-biofuels-and-more|title=Engineering Algae to Make the 'Wonder Material' Nanocellulose for Biofuels and More|website=newswise.com}}</ref>

At ICAR-Central Institute for Research on Cotton Technology, Mumbai, India, a novel chemo-mechanical process for production of nanocellulose from cotton linters has been developed in the year 2013. To demonstrate this technology to the industrial users, a nanocellulose pilot plant is now operational at this Institute in Mumbai with a capacity of 10&nbsp;kg per day. This facility was inaugurated in 2015.<ref>{{cite web|url=http://www.nanocellulose.in|title=Nanocellulose - NaNo Research GROUP @ ICAR-CIRCOT, Mumbai}}</ref>

==Structure and properties==
[[File:AFM Innventia nanocellulose.JPG|right|thumb|AFM height image of carboxymethylated nanocellulose adsorbed on a silica surface. The scanned surface area is 1 µm<sup>2</sup>.]]

===Dimensions and crystallinity===
The ultrastructure of nanocellulose derived from various sources has been extensively studied. Techniques such as [[transmission electron microscopy]] (TEM), [[scanning electron microscopy]] (SEM), [[atomic force microscopy]] (AFM), [[wide angle X-ray scattering]] (WAXS), small incidence angle X-ray diffraction and solid state <sup>13</sup>C cross-polarization [[magic angle spinning]] (CP/MAS), [[nuclear magnetic resonance]] (NMR) and [[spectroscopy]] have been used to characterize typically dried nanocellulose morphology.<ref name="Siro2010"/>

A combination of microscopic techniques with image analysis can provide information on fibril widths, it is more difficult to determine fibril lengths, because of entanglements and difficulties in identifying both ends of individual nanofibrils.<ref name=Chinga-Carrasco2011a>{{cite journal|last=Chinga-Carrasco|first=G.|author2=Yu, Y. |author3=Diserud, O. |title=Quantitative Electron Microscopy of Cellulose Nanofibril Structures from Eucalyptus and Pinus radiata Kraft Pulp Fibers|journal=Microscopy and Microanalysis|date=21 July 2011|volume=17|issue=4|pages=563–571|bibcode = 2011MiMic..17..563C |doi = 10.1017/S1431927611000444 |pmid=21740618}}</ref><ref name=Chinga-Carrasco2011c>{{cite book|vauthors = Chinga-Carrasco G, Miettinen A, Luengo Hendriks CL, Gamstedt EK, Kataja M|title=Structural Characterisation of Kraft Pulp Fibres and Their Nanofibrillated Materials for Biodegradable Composite Applications| year=2011| publisher=InTech| isbn=978-953-307-352-1}}</ref>{{page needed|date=March 2017}} Also, nanocellulose suspensions may not be homogeneous and can consist of various structural components, including cellulose nanofibrils and nanofibril bundles.<ref name=Chinga-Carrasco2011b>{{cite journal|last=Chinga-Carrasco|first=G.|title=Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view|journal=Nanoscale Research Letters|date=13 June 2011|volume=6|page=417|bibcode = 2011NRL.....6..417C |doi = 10.1186/1556-276X-6-417|pmid=21711944|pmc=3211513|issue=1}}</ref>

In a study of enzymatically pre-treated nanocellulose fibrils in a suspension the size and size-distribution were established using cryo-TEM. The fibrils were found to be rather mono-dispersed mostly with a diameter of ca. 5&nbsp;nm although occasionally thicker fibril bundles were present.<ref name="Paakko2007"/> By combining ultrasonication with an "oxidation pretreatment", cellulose microfibrils with a lateral dimension below 1&nbsp;nm has been observed by AFM. The lower end of the thickness dimension is around 0.4&nbsp;nm, which is related to the thickness of a cellulose monolayer sheet.<ref>{{cite journal|last=Li|first=Qingqing|author2=Scott Renneckar|title=Supramolecular Structure Characterization of Molecularly Thin Cellulose I Nanoparticles|journal=Biomacromolecules|date=6 January 2011| volume=12| issue=3| pages=650–659| doi=10.1021/bm101315y| pmid=21210665}}</ref>

Aggregate widths can be determined by CP/MAS NMR developed by [[Innventia|Innventia AB]], Sweden, which also has been demonstrated to work for nanocellulose (enzymatic pre-treatment). An average width of 17&nbsp;nm has been measured with the NMR-method, which corresponds well with SEM and TEM. Using TEM, values of 15&nbsp;nm have been reported for nanocellulose from carboxymethylated pulp. However, thinner fibrils can also be detected. Wågberg et al. reported fibril widths of 5–15&nbsp;nm for a nanocellulose with a charge density of about 0.5 meq./g.<ref name="Wagberg2008"/> The group of Isogai reported fibril widths of 3–5&nbsp;nm for TEMPO-oxidized cellulose having a charge density of 1.5 meq./g.<ref name="Fukuzumi2009"/>

Pulp chemistry has a significant influence on nanocellulose microstructure. Carboxymethylation increases the numbers of charged groups on the fibril surfaces, making the fibrils easier to liberate and results in smaller and more uniform fibril widths (5–15&nbsp;nm) compared to enzymatically pre-treated nanocellulose, where the fibril widths were 10–30&nbsp;nm.<ref name="Aulin2009"/> The degree of crystallinity and crystal structure of nanocellulose. Nanocellulose exhibits cellulose crystal I organization and the degree of crystallinity is unchanged by the preparation of the nanocellulose. Typical values for the degree of crystallinity were around 63%.<ref name="Aulin2009"/>

===Viscosity===
The unique [[rheology]] of nanocellulose dispersions was recognized by the early investigators.<ref name="tatsumi2002"/> The high [[viscosity]] at low nanocellulose concentrations makes nanocellulose very interesting as a non-caloric stabilizer and gellant in food applications, the major field explored by the early investigators.

The dynamic [[Rheometry|rheological]] properties were investigated in great detail<ref name="Paakko2007"/> and revealed that the storage and loss modulus were independent of the angular frequency at all nanocellulose concentrations between 0.125% to 5.9%. The storage modulus values are particularly high (104 Pa at 3% concentration)<ref name="Paakko2007"/> compared to results for cellulose nanowhiskers (102 Pa at 3% concentration).<ref name="tatsumi2002"/> There is also a particular strong concentration dependence as the storage modulus increases 5 orders of magnitude if the concentration is increased from 0.125% to 5.9%.

Nanocellulose gels are also highly shear thinning (the viscosity is lost upon introduction of the shear forces). The shear-thinning behaviour is particularly useful in a range of different coating applications.<ref name="Paakko2007"/>

===Mechanical properties===
Crystalline cellulose has interesting mechanical properties for use in material applications. Its tensile strength is about 500MPa{{Citation needed|date=October 2014}}, similar to that of aluminium. Its stiffness is about 140–220&nbsp;GPa, comparable with that of [[Kevlar]] and better than that of glass fiber, both of which are used commercially to reinforce plastics. Films made from nanocellulose have high strength (over 200&nbsp;[[MPa]]), high stiffness (around 20&nbsp;[[GPa]])<ref name="Henriksson2008"/> and high strain{{clarify|date=May 2013}} (12%). Its strength/weight ratio is 8 times that of stainless steel.<ref name=ns>{{cite web|url=https://www.newscientist.com/article/mg21528786.100-why-wood-pulp-is-worlds-new-wonder-material.html |title=Why wood pulp is world's new wonder material – tech – 23 August 2012 |publisher=New Scientist |accessdate=2012-08-30}}</ref> Fibers made from nanocellulose have high strength (up to 1.57 GPa) and stiffness (up to 86 GPa).<ref name="Mittal2018"/>

===Barrier properties===
In semi-crystalline polymers, the crystalline regions are considered to be gas impermeable. Due to relatively high crystallinity,<ref name="Aulin2009"/> in combination with the ability of the nanofibers to form a dense network held together by strong inter-fibrillar bonds (high cohesive energy density), it has been suggested that nanocellulose might act as a barrier material.<ref name="Fukuzumi2009"/><ref name="Aulin2010a"/><ref name="Syverud2009"/> Although the number of reported oxygen permeability values are limited, reports attribute high oxygen barrier properties to nanocellulose films. One study reported an oxygen permeability of 0.0006 (cm<sup>3</sup>&nbsp;µm)/(m<sup>2</sup>&nbsp;day&nbsp;kPa) for a ca. 5&nbsp;µm thin nanocellulose film at 23&nbsp;°C and 0% RH.<ref name="Aulin2010a"/> In a related study, a more than 700-fold decrease in oxygen permeability of a polylactide (PLA) film when a nanocellulose layer was added to the PLA surface was reported.<ref name="Fukuzumi2009"/>

The influence of nanocellulose film density and porosity on film oxygen permeability has recently been explored.<ref name=Chinga-Carrasco2012>{{cite journal|last=Chinga-Carrasco|first=G.|author2=Syverud K.|title=On the structure and oxygen transmission rate of biodegradable cellulose nanobarriers|journal=Nanoscale Research Letters|date=19 March 2012|volume=7|page=192|bibcode = 2012NRL.....7..192C |doi = 10.1186/1556-276X-7-192|pmid=22429336|pmc=3324384|issue=1}}</ref> Some authors have reported significant porosity in nanocellulose films,<ref name="Henriksson2007"/><ref name="Henriksson2008"/><ref name="Svagan2007"/> which seems to be in contradiction with high oxygen barrier properties, whereas Aulin et al.<ref name="Aulin2010a"/> measured a nanocellulose film density close to density of crystalline cellulose (cellulose Iß crystal structure, 1.63&nbsp;g/cm<sup>3</sup>)<ref name="Diddens2008"/> indicating a very dense film with a porosity close to zero.

Changing the surface functionality of the cellulose nanoparticle can also affect the permeability of nanocellulose films. Films constituted of negatively charged cellulose nanowhiskers could effectively reduce permeation of negatively charged ions, while leaving neutral ions virtually unaffected. Positively charged ions were found to accumulate in the membrane.<ref name="permselective2009"/>

[[Multi-Parametric Surface Plasmon Resonance]] is one of the methods to study barrier properties of natural, modified or coated nanocellulose. The different antifouling, moisture, solvent, antimicrobial barrier formulation quality can be measured on the nanoscale. The adsorption kinetics as well as the degree of swelling can be measured in real-time and label-free.<ref>{{cite journal|last1=Mohan|first1=Tamilselvan|last2=Niegelhell|first2=Katrin|last3=Zarth|first3=Cíntia Salomão Pinto|last4=Kargl|first4=Rupert|last5=Köstler|first5=Stefan|last6=Ribitsch|first6=Volker|last7=Heinze|first7=Thomas|last8=Spirk|first8=Stefan|last9=Stana-Kleinschek|first9=Karin|title=Triggering Protein Adsorption on Tailored Cationic Cellulose Surfaces|journal=Biomacromolecules|date=10 November 2014|volume=15|issue=11|pages=3931–3941|doi=10.1021/bm500997s|pmid=25233035}}</ref><ref>{{cite journal|title=Effect of Molecular Architecture of PDMAEMA–POEGMA Random and Block Copolymers on Their Adsorption on Regenerated and Anionic Nanocelluloses and Evidence of Interfacial Water Expulsion |last1 = Vuoriluoto |first1 = Maija | last2 = Orelma | first2=Hannes | last3 = Johansson | first3 = Leena-Sisko | last4 = Zhu | first4 = Baolei | last5 = Poutanen | first5 = Mikko | last6 = Walther | first6 = Andreas | last7 = Laine | first7 = Janne | last8 = Rojas | first8 = Orlando J. | doi=10.1021/acs.jpcb.5b07628 |pmid = 26560798 | journal= The Journal of Physical Chemistry B | volume= 119|issue=49 |pages= 5275–15286|year = 2015 }}</ref>

===Foams===
Nanocellulose can also be used to make [[aerogels]]/foams, either homogeneously or in composite formulations. Nanocellulose-based foams are being studied for packaging applications in order to replace [[polystyrene]]-based foams. Svagan et al. showed that nanocellulose has the ability to reinforce [[starch]] foams by using a freeze-drying technique.<ref name="Svagan2008"/> The advantage of using nanocellulose instead of [[wood pulp|wood-based pulp fibers]] is that the nanofibrils can reinforce the thin cells in the starch foam. Moreover, it is possible to prepare pure nanocellulose aerogels applying various freeze-drying and super critical {{chem|CO|2}} drying techniques. Aerogels and foams can be used as porous templates.<ref name="Paako2008"/><ref name="Heath2010"/> Tough ultra-high porosity foams prepared from cellulose I nanofibril suspensions were studied by Sehaqui et al. a wide range of mechanical properties including compression was obtained by controlling density and nanofibril interaction in the foams.<ref name="Sehaqui2010"/> Cellulose nanowhiskers could also be made to gel in water under low power sonication giving rise to aerogels with the highest reported surface area (>600m2/g) and lowest shrinkage during drying (6.5%) of cellulose aerogels.<ref name="Heath2010"/> In another study by Aulin et al.,<ref name="Aulin2010b"/> the formation of structured porous aerogels of nanocellulose by freeze-drying was demonstrated. The density and surface texture of the aerogels was tuned by selecting the concentration of the nanocellulose dispersions before freeze-drying. [[Chemical vapour deposition]] of a fluorinated [[silane]] was used to uniformly coat the aerogel to tune their wetting properties towards non-polar liquids/oils. The authors demonstrated that it is possible to switch the wettability behaviour of the cellulose surfaces between super-wetting and super-repellent, using different scales of roughness and porosity created by the freeze-drying technique and change of concentration of the nanocellulose dispersion. Structured porous cellulose foams can however also be obtained by utilizing the freeze-drying technique on cellulose generated by Gluconobacter strains of bacteria, which bio-synthesize open porous networks of cellulose fibers with relatively large amounts of nanofibrils dispersed inside. Olsson et al.<ref>{{cite journal|last1=Olsson|first1=R. T.|last2=Azizi Samir|first2=M. A. S.|last3=Salazar-Alvarez|first3=G.|last4=Belova|first4=L.|last5=Ström|first5=V.|last6=Berglund|first6=L. A.|last7=Ikkala|first7=O.|last8=Nogués|first8=J.|last9=Gedde|first9=U. W.|title=Making flexible magnetic aerogels and stiff magnetic nanopaper using cellulose nanofibrils as templates|journal=Nature Nanotechnology|volume=5|pages=584–8|year=2010|doi=10.1038/nnano.2010.155|bibcode = 2010NatNa...5..584O|issue=8|pmid=20676090}}</ref> demonstrated that these networks can be further impregnated with metalhydroxide/oxide precursors, which can readily be transformed into grafted magnetic nanoparticles along the cellulose nanofibers. The magnetic cellulose foam may allow for a number of novel applications of nanocellulose and the first remotely actuated magnetic super sponges absorbing 1&nbsp;gram of water within a 60&nbsp;mg cellulose aerogel foam were reported. Notably, these highly porous foams (>98% air) can be compressed into strong magnetic nanopapers, which may find use as functional membranes in various applications.

===Surface modification===
The surface modification of nanocellulose is currently receiving a large amount of attention.<ref name="Eichhorn review 2010"/> Nanocellulose displays a high concentration of hydroxyl groups at the surface which can be reacted. However, hydrogen bonding strongly affects the reactivity of the surface hydroxyl groups. In addition, impurities at the surface of nanocellulose such as glucosidic and lignin fragments need to be removed before surface modification to obtain acceptable reproducibility between different batches.<ref name="Labet2011"/>

===Safety aspects===
Health, safety and environmental aspects of nanocellulose have been recently evaluated. Processing of nanocellulose does not cause significant exposure to fine particles during friction grinding or spray drying. No evidence of inflammatory effects or cytotoxicity on mouse or human macrophages can be observed after exposure to nanocellulose. The results of toxicity studies suggest that nanocellulose is not cytotoxic and does not cause any effects on inflammatory system in macrophages. In addition, nanocellulose is not acutely toxic to [[Aliivibrio fischeri|Vibrio fischeri]] in environmentally relevant concentrations.<ref name="Vartiainen2011"/>

==Applications==
The properties of nanocellulose (e.g. mechanical properties, film-forming properties, viscosity etc.) makes it an interesting material for many applications and the potential for a multibillion-dollar industry.<ref>{{cite journal |doi=10.1021/bm3019467 |pmid=23421631 |title=Potential of Nanocrystalline Cellulose–Fibrin Nanocomposites for Artificial Vascular Graft Applications |journal=Biomacromolecules |volume=14 |issue=4 |pages=1063–71 |year=2013 |last1=Brown |first1=Elvie E. |last2=Hu |first2=Dehong |last3=Abu Lail |first3=Nehal |last4=Zhang |first4=Xiao }}</ref>

===Paper and paperboard===
[[File:Nanocellulose recycling 2.jpg|thumb|upright=2|Nanocellulose recycling chart<ref>{{cite journal|doi=10.1080/14686996.2017.1364976|pmid=28970870|pmc=5613913|title=Development and applications of transparent conductive nanocellulose paper|journal=Science and Technology of Advanced Materials|volume=18|issue=1|pages=620–633|year=2017|last1=Li|first1=Shaohui|last2=Lee|first2=Pooi See}}</ref>]]
[[File:GaAs electronics on nanocellulose.jpg|thumb|[[GaAs]] electronics on nanocellulose substrate<ref name=bio>{{cite journal|doi=10.1038/ncomms8170|pmid=26006731|pmc=4455139|title=High-performance green flexible electronics based on biodegradable cellulose nanofibril paper|journal=Nature Communications|volume=6|pages=7170|year=2015|last1=Jung|first1=Yei Hwan|last2=Chang|first2=Tzu-Hsuan|last3=Zhang|first3=Huilong|last4=Yao|first4=Chunhua|last5=Zheng|first5=Qifeng|last6=Yang|first6=Vina W.|last7=Mi|first7=Hongyi|last8=Kim|first8=Munho|last9=Cho|first9=Sang June|last10=Park|first10=Dong-Wook|last11=Jiang|first11=Hao|last12=Lee|first12=Juhwan|last13=Qiu|first13=Yijie|last14=Zhou|first14=Weidong|last15=Cai|first15=Zhiyong|last16=Gong|first16=Shaoqin|last17=Ma|first17=Zhenqiang|bibcode=2015NatCo...6E7170J}}</ref>]]
[[File:Nanocellulose solar cell.jpg|thumb|Bendable solar cell on nanocellulose substrate]]
There is potential of nanocellulose applications in the area of paper and paperboard manufacture. Nanocelluloses are expected to enhance the fiber-fiber bond strength and, hence, have a strong reinforcement effect on paper materials.<ref>{{cite journal | last1 = Taipale | first1 = T. | last2 = Österberg | first2 = M. | last3 = Nykänen | first3 = A. | last4 = Ruokolainen | first4 = J. | last5 = Laine | first5 = J. | year = 2010 | title = Effect of microfibrillated cellulose and fines on the drainage of kraft pulp suspension and paper strength | url = | journal = Cellulose | volume = 17 | issue = 5| pages = 1005–1020 | doi=10.1007/s10570-010-9431-9}}</ref><ref>{{cite journal | last1 = Eriksen | first1 = Ø. | last2 = Syverud | first2 = K. | last3 = Gregersen | first3 = Ø. W. | year = 2008 | title = The use of microfibrillated cellulose produced from kraft pulp as strength enhancer in TMP paper | url = | journal = Nord. Pulp Pap. Res. J. | volume = 23 | issue = 3| pages = 299–304 | doi=10.3183/npprj-2008-23-03-p299-304}}</ref><ref>{{cite journal | last1 = Ahola | first1 = S. | last2 = Österberg | first2 = M. | last3 = Laine | first3 = J. | year = 2007 | title = Cellulose nanofibrils—adsorption with poly(amideamine) epichlorohydrin studied by QCM-D and application as a paper strength additive | url = | journal = Cellulose | volume = 15 | issue = 2| pages = 303–314 | doi=10.1007/s10570-007-9167-3}}</ref> Nanocellulose may be useful as a barrier in grease-proof type of papers and as a wet-end additive to enhance retention, dry and wet strength in commodity type of paper and board products.<ref>{{cite journal | last1 = Syverud | first1 = K. | last2 = Stenius | first2 = P. | year = 2008 | title = Strength and barrier properties of MFC films | url = | journal = Cellulose | volume = 16 | issue = | pages = 75–85 | doi=10.1007/s10570-008-9244-2}}</ref><ref>{{cite journal | last1 = Aulin | first1 = C. | last2 = Gällstedt | first2 = M. | last3 = Lindström | first3 = T. | year = 2010 | title = Oxygen and oil barrier properties of microfibrillated cellulose films and coatings | url = | journal = Cellulose | volume = 17 | issue = 3| pages = 559–574 | doi=10.1007/s10570-009-9393-y}}</ref><ref>{{cite journal | last1 = Lavoine | first1 = N. | last2 = Desloges | first2 = I. | last3 = Dufresne | first3 = A. | last4 = Bras | first4 = J. | year = 2012 | title = Microfibrillated cellulose - its barrier properties and applications in cellulosic materials: a review | url = | journal = Carbohydr. Polym | volume = 90 | issue = 2| pages = 735–64 | doi=10.1016/j.carbpol.2012.05.026| pmid = 22839998 }}</ref><ref>{{cite journal | last1 = Missoum | first1 = K. | last2 = Martoïa | first2 = F. | last3 = Belgacem | first3 = M. N. | last4 = Bras | first4 = J. | year = 2013 | title = Effect of chemically modified nanofibrillated cellulose addition on the properties of fiber-based materials | url = | journal = Ind. Crops Prod. | volume = 48 | issue = | pages = 98–105 | doi=10.1016/j.indcrop.2013.04.013}}</ref> It has been shown that applying CNF as a coating material on the surface of paper and paperboard improves the barrier properties, especially air resistance. It also enhances the structure properties of paperboards (smoother surface).<ref>{{Cite journal|last=Mazhari Mousavi|first=Seyyed Mohammad|display-authors=etal|year=2016|title=Cellulose nanofibers with higher solid content as a coating material to improve the structure and barrier properties of paperboard|url=|journal=TAPPI Conference Proceedings|volume=|pages=1–7|via=}}</ref>

Nanocellulose can be used to prepare flexible and optically transparent paper. Such paper is an attractive substrate for electronic devices because it is recyclable, compatible with biological objects, and easily degrades when disposed of.<ref name=bio/>

Like resin-free lignocellulose fiberboard which are produced using wet process, high tough cellulose nanofiber board with thickness of 3&nbsp;mm was also introduced by Yousefi et al., 2018.

===Composite===
As described above the properties of the nanocellulose makes an interesting material for reinforcing plastics. Nanocellulose has been reported to improve the mechanical properties of, for example, thermosetting resins, [[starch]]-based matrixes, [[soy protein]], [[rubber latex]], [[Polylactic acid|poly(lactide)]]. The composite applications may be for use as coatings and films,<ref>{{Cite journal|last=Gamelas|first=José António Ferreira|last2=Ferraz|first2=Eduardo|date=2015-08-05|title=Composite Films Based on Nanocellulose and Nanoclay Minerals as High Strength Materials with Gas Barrier Capabilities: Key Points and Challenges|url=http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_10_4_6310_Gamelas_Editorial_Composite_Films_Nanocellulose_Nanoclay|journal=BioResources|language=en|volume=10|issue=4|pages=6310–6313|doi=10.15376/biores.10.4.6310-6313|issn=1930-2126|via=}}</ref> paints, foams, packaging.

===Food===
Nanocellulose can be used as a low calorie replacement for today’s carbohydrate additives used as thickeners, flavour carriers and suspension stabilizers in a wide variety of food products and is useful for producing fillings, crushes, chips, wafers, soups, gravies, puddings etc. The food applications were early recognised as a highly interesting application field for nanocellulose due to the rheological behaviour of the nanocellulose gel.

===Hygiene and absorbent products===
Applications in this field include: Super water absorbent material (e.g. for incontinence pads material), nanocellulose used together with super absorbent polymers, nanocellulose in tissue, non-woven products or absorbent structures and as antimicrobial films. {{citation needed|date=March 2017}}

===Emulsion and dispersion===
Nanocellulose has numerous applications as a food additive, and in the general area of emulsion and dispersion applications in other fields.<ref name=Xhanari2011>{{cite journal|last=Xhanari|first=K.|author2=Syverud, K. |author3=Stenius, P. |title=Emulsions stabilized by microfibrillated cellulose: the effect of hydrophobization, concentration and o/w ratio|journal=Dispersion Science and Technology|year=2011|volume=32|issue=3|pages=447–452|doi=10.1080/01932691003658942}}</ref><ref>{{cite journal|last=Lif|first=A. |author2=Stenstad, P. |author3=Syverud, K. |author4=Nydén, M. |author5=Holmberg, K.|title=Fischer-Tropsch diesel emulsions stabilised by microfibrillated cellulose|journal=Colloid and Interface Science|volume=352|issue=2|pages=585–592|doi=10.1016/j.jcis.2010.08.052|pmid=20864117 |year=2010 |bibcode=2010JCIS..352..585L}}</ref> Oil in water applications were early recognized. Early investigators had explored the area of non-settling suspensions for pumping sand, coal as well as paints and drilling muds.{{citation needed|date=March 2017}}

===Oil recovery===
Hydrocarbon fracturing of oil-bearing formations is a potentially interesting and large-scale application. Nanocellulose has been suggested for use in [[Petroleum extraction|oil recovery]] applications as a fracturing fluid. Drilling muds based on nanocellulose have also been suggested.{{citation needed|date=March 2017}}

===Medical, cosmetic and pharmaceutical===
The use of nanocellulose in cosmetics and pharmaceuticals was also early recognized. A wide range of high-end applications have been suggested:
* Freeze-dried nanocellulose aerogels used in sanitary napkins, tampons, diapers or as [http://www.pfi.no/New-Biomaterials/Projects/NanoHeal/ wound dressing]
* The use of nanocellulose as a composite coating agent in cosmetics e.g. for hair, eyelashes, eyebrows or nails
* A dry solid nanocellulose composition in the form of tablets for treating intestinal disorders
* Nanocellulose films for screening of biological compounds and nucleic acids encoding a biological compound
* Filter medium partly based on nanocellulose for leukocyte free blood transfusion
* A buccodental formulation, comprising nanocellulose and a polyhydroxylated organic compound
* Powdered nanocellulose has also been suggested as an excipient in pharmaceutical compositions
* Nanocellulose in compositions of a photoreactive noxious substance purging agent
* Elastic cryo-structured gels for potential biomedical and biotechnological application.<ref name=Syverud2011>{{cite journal|last=Syverud|first=K.|author2=Kirsebom, H. |author3=Hajizadeh, S. |author4=Chinga-Carrasco, G. |title=Cross-linking cellulose nanofibrils for potential elastic cryo-structured gels|journal=Nanoscale Research Letters|date=12 December 2011|volume=6|page=626|bibcode = 2011NRL.....6..626S |doi = 10.1186/1556-276X-6-626 |pmid=22152032|pmc=3260332|issue=1}}</ref>
* [[3D cell culture in wood-based nanocellulose hydrogel|Matrix for 3D cell culture]]

===Other applications===
* As a highly scattering material for ultra-white coatings.<ref>{{cite journal |last1=Toivonen |first1=Matti S.|last2=Onelli |first2=Olimpia D. |last3=Jacucci |first3= Gianni |last4=Lovikka|first4=Ville |last5=Rojas |first5=Orlando J. |last6=Ikkala |first6=Olli|last7=Vignolini |first7=Silvia |date=13 March 2018 |title=Anomalous-Diffusion-Assisted Brightness in White Cellulose Nanofibril Membranes
|journal=Advanced Materials |volume= 30|issue= 16|pages= 1704050|doi=10.1002/adma.201704050 |pmid=29532967}}</ref>
* Activate the dissolution of cellulose in different solvents
* Regenerated cellulose products, such as fibers films, cellulose derivatives
* Tobacco filter additive
* Organometallic modified nanocellulose in battery separators
* Reinforcement of conductive materials
* Loud-speaker [[Acoustic membrane|membranes]]
* High-flux [[Artificial membrane|membranes]]
* Computer components<ref name=ns/><ref name="Dandekar2016">{{cite patent | country = WO | number = 2016174104 A1 | status = application | title = Modified bacterial nanocellulose and its uses in chip cards and medicine | pubdate = 2016-11-03 | fdate = 2016-04-27 | pridate = 2015-04-27 | invent1 = Thomas Dandekar | assign1 = Julius-Maximilians-Universität Würzburg}}</ref>
* Capacitors<ref name="NyströmMarais2015">{{cite journal|last1=Nyström|first1=Gustav|last2=Marais|first2=Andrew|last3=Karabulut|first3=Erdem|last4=Wågberg|first4=Lars|last5=Cui|first5=Yi|last6=Hamedi|first6=Mahiar M.|title=Self-assembled three-dimensional and compressible interdigitated thin-film supercapacitors and batteries|journal=Nature Communications|volume=6|year=2015|pages=7259|issn=2041-1723|doi=10.1038/ncomms8259|bibcode = 2015NatCo...6E7259N|pmid=26021485|pmc=4458871}}</ref>
* Lightweight body armour and ballistic glass<ref name=ns/>
* Corrosion inhibitors<ref>Garner, A. (2015-2016) {{US Patent|9222174}} "Corrosion inhibitor comprising cellulose nanocrystals and cellulose nanocrystals in combination with a corrosion inhibitor" and {{US Patent|9359678}} "Use of charged cellulose nanocrystals for corrosion inhibition and a corrosion inhibiting composition comprising the same".</ref>

==Commercial production==
Although wood-driven nanocellulose was first produced in 1983 by Herrick and Turbak, its commercial production postponed till 2010, mainly due to the high production energy consumption and high production cost. Inventia Co. in Sweden was the first nanocellulose company established in 2010. Other first-generation active companies include CelluForce (Canada), Kruger (Canada), Performance BioFilaments (Canada), Nippon (Japan), Nano Novin Polymer Co. (Iran), Maine University (USA), VTT (Finland), Sappi (Netherlands), InoFib (France), and Melodea (Israel). The largest MFC production unit in the world is located at Stora Enzo's production facilities located at it's mill in Imatra Finland.

==See also==
* [[Cellulose]]
* [[Cellulose fiber]]
* [[Microcrystalline cellulose]]
* [[Composite material]]

==References==
{{Reflist|colwidth=30em|refs=

Revision as of 10:20, 2 July 2019

Nanocellulose

Nanocellulose is a term referring to nano-structured cellulose. This may be either cellulose nanocrystal (CNC or NCC), cellulose nanofibers (CNF) also called microfibrillated cellulose (MFC), or bacterial nanocellulose, which refers to nano-structured cellulose produced by bacteria.

CNF is a material composed of nanosized cellulose fibrils with a high aspect ratio (length to width ratio). Typical fibril widths are 5–20 nanometers with a wide range of lengths, typically several micrometers. It is pseudo-plastic and exhibits thixotropy, the property of certain gels or fluids that are thick (viscous) under normal conditions, but become less viscous when shaken or agitated. When the shearing forces are removed the gel regains much of its original state. The fibrils are isolated from any cellulose containing source including wood-based fibers (pulp fibers) through high-pressure, high temperature and high velocity impact homogenization, grinding or microfluidization (see manufacture below).

Nanocellulose can also be obtained from native fibers by an acid hydrolysis, giving rise to highly crystalline and rigid nanoparticles which are shorter (100s to 1000 nanometers) than the nanofibrils obtained through homogenization, microfluiodization or grinding routes. The resulting material is known as cellulose nanocrystal (CNC).[1]

History and terminology

The terminology microfibrillated/nanocellulose or (MFC) was first used by Turbak, Snyder and Sandberg in the late 1970s at the ITT Rayonier labs in Whippany, New Jersey, USA to describe a product prepared as a gel type material by passing wood pulp through a Gaulin type milk homogenizer at high temperatures and high pressures followed by ejection impact against a hard surface.[citation needed]

The terminology first appeared publicly in the early 1980s when a number of patents and publications were issued to ITT Rayonier on a new nanocellulose composition of matter.[2] In later work Herrick[who?] at Rayonier also published work on making a dry powder form of the gel.[3] Rayonier has been one of the world's premier producers of purified pulps interested in creating new uses and new markets for pulps and not to compete with new customers. Thus, as the patents issued,[4] Rayonier gave free license to whoever wanted to pursue this new use for cellulose. Rayonier, as a company, never pursued scale-up. Rather, Turbak et al. pursued 1) finding new uses for the MFC/nanocellulose. These included using MFC as a thickener and binder in foods, cosmetics, paper formation, textiles, nonwovens, etc. and 2) evaluate swelling and other techniques for lowering the energy requirements for MFC/Nanocellulose production.[5] After ITT closed the Rayonier Whippany Labs in 1983–84, Herric worked on making a dry powder form of MFC at the Rayonier labs in Shelton, Washington, USA[3]

In the mid 1990s the group of Taniguchi and co-workers and later Yano and co-workers pursued the effort in Japan.[6] and a host of major companies, see numerous U.S. patents issued to P&G, J&J, 3M, McNeil, etc. using U.S. patent search under inventor name Turbak search base.

Manufacture

Nanocellulose, which is also called cellulose nanofibers (CNF), microfibrillated cellulose (MFC) or cellulose nanocrystal (CNC), can be prepared from any cellulose source material, but woodpulp is normally used.

The nanocellulose fibrils may be isolated from the wood-based fibers using mechanical methods which expose the pulp to high shear forces, ripping the larger wood-fibres apart into nanofibers. For this purpose, high-pressure homogenizers, ultrasonic homogenizers,[7][better source needed] grinders or microfluidizers can be used.[citation needed] The homogenizers are used to delaminate the cell walls of the fibers and liberate the nanosized fibrils. This process consumes very large amounts of energy and values over 30 MWh/tonne are not uncommon.[citation needed]

To address this problem, sometimes enzymatic/mechanical pre-treatments[8] and introduction of charged groups for example through carboxymethylation[9] or TEMPO-mediated oxidation are used.[10] These pre-treatments can decrease energy consumption below 1 MWh/tonne.[11] Recently, a new method "Nitro-oxidation" has been developed to prepare carboxycellulose nanofibers directly from raw plant biomass. Due to less number of processing steps to extract nanocellulose, Nitro-oxidation method has found to be a cost-effective, less-chemically oriented and efficient method to extract carboxycellulose nanofibers.[12] [13] Functionalized nanofibers obtained using nitro-oxidation has found excellent substrate to remove heavy metal ions impurities such as lead[14] cadmium[15] uranium[16]


Cellulose nanowhiskers are rodlike highly crystalline particles (relative crystallinity index above 75%) with a rectangular cross section. They are formed by the acid hydrolysis of native cellulose fibers commonly using sulfuric or hydrochloric acid. Amorphous sections of native cellulose are hydrolysed and after careful timing, crystalline sections can be retrieved from the acid solution by centrifugation and washing. Their dimensions depend on the native cellulose source material, and hydrolysis time and temperature.[citation needed]

Spherical shape carboxycellulose nanoparticles prepared by nitric acid-phosphoric acid treatment has found to stable in dispersion in its non-ionic form.[17] In April 2013 breakthroughs[clarification needed] in nanocellulose production were announced at an American Chemical Society conference.[18]

At ICAR-Central Institute for Research on Cotton Technology, Mumbai, India, a novel chemo-mechanical process for production of nanocellulose from cotton linters has been developed in the year 2013. To demonstrate this technology to the industrial users, a nanocellulose pilot plant is now operational at this Institute in Mumbai with a capacity of 10 kg per day. This facility was inaugurated in 2015.[19]

Structure and properties

AFM height image of carboxymethylated nanocellulose adsorbed on a silica surface. The scanned surface area is 1 µm2.

Dimensions and crystallinity

The ultrastructure of nanocellulose derived from various sources has been extensively studied. Techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), wide angle X-ray scattering (WAXS), small incidence angle X-ray diffraction and solid state 13C cross-polarization magic angle spinning (CP/MAS), nuclear magnetic resonance (NMR) and spectroscopy have been used to characterize typically dried nanocellulose morphology.[20]

A combination of microscopic techniques with image analysis can provide information on fibril widths, it is more difficult to determine fibril lengths, because of entanglements and difficulties in identifying both ends of individual nanofibrils.[21][22][page needed] Also, nanocellulose suspensions may not be homogeneous and can consist of various structural components, including cellulose nanofibrils and nanofibril bundles.[23]

In a study of enzymatically pre-treated nanocellulose fibrils in a suspension the size and size-distribution were established using cryo-TEM. The fibrils were found to be rather mono-dispersed mostly with a diameter of ca. 5 nm although occasionally thicker fibril bundles were present.[8] By combining ultrasonication with an "oxidation pretreatment", cellulose microfibrils with a lateral dimension below 1 nm has been observed by AFM. The lower end of the thickness dimension is around 0.4 nm, which is related to the thickness of a cellulose monolayer sheet.[24]

Aggregate widths can be determined by CP/MAS NMR developed by Innventia AB, Sweden, which also has been demonstrated to work for nanocellulose (enzymatic pre-treatment). An average width of 17 nm has been measured with the NMR-method, which corresponds well with SEM and TEM. Using TEM, values of 15 nm have been reported for nanocellulose from carboxymethylated pulp. However, thinner fibrils can also be detected. Wågberg et al. reported fibril widths of 5–15 nm for a nanocellulose with a charge density of about 0.5 meq./g.[9] The group of Isogai reported fibril widths of 3–5 nm for TEMPO-oxidized cellulose having a charge density of 1.5 meq./g.[25]

Pulp chemistry has a significant influence on nanocellulose microstructure. Carboxymethylation increases the numbers of charged groups on the fibril surfaces, making the fibrils easier to liberate and results in smaller and more uniform fibril widths (5–15 nm) compared to enzymatically pre-treated nanocellulose, where the fibril widths were 10–30 nm.[26] The degree of crystallinity and crystal structure of nanocellulose. Nanocellulose exhibits cellulose crystal I organization and the degree of crystallinity is unchanged by the preparation of the nanocellulose. Typical values for the degree of crystallinity were around 63%.[26]

Viscosity

The unique rheology of nanocellulose dispersions was recognized by the early investigators.[27] The high viscosity at low nanocellulose concentrations makes nanocellulose very interesting as a non-caloric stabilizer and gellant in food applications, the major field explored by the early investigators.

The dynamic rheological properties were investigated in great detail[8] and revealed that the storage and loss modulus were independent of the angular frequency at all nanocellulose concentrations between 0.125% to 5.9%. The storage modulus values are particularly high (104 Pa at 3% concentration)[8] compared to results for cellulose nanowhiskers (102 Pa at 3% concentration).[27] There is also a particular strong concentration dependence as the storage modulus increases 5 orders of magnitude if the concentration is increased from 0.125% to 5.9%.

Nanocellulose gels are also highly shear thinning (the viscosity is lost upon introduction of the shear forces). The shear-thinning behaviour is particularly useful in a range of different coating applications.[8]

Mechanical properties

Crystalline cellulose has interesting mechanical properties for use in material applications. Its tensile strength is about 500MPa[citation needed], similar to that of aluminium. Its stiffness is about 140–220 GPa, comparable with that of Kevlar and better than that of glass fiber, both of which are used commercially to reinforce plastics. Films made from nanocellulose have high strength (over 200 MPa), high stiffness (around 20 GPa)[28] and high strain[clarification needed] (12%). Its strength/weight ratio is 8 times that of stainless steel.[29] Fibers made from nanocellulose have high strength (up to 1.57 GPa) and stiffness (up to 86 GPa).[30]

Barrier properties

In semi-crystalline polymers, the crystalline regions are considered to be gas impermeable. Due to relatively high crystallinity,[26] in combination with the ability of the nanofibers to form a dense network held together by strong inter-fibrillar bonds (high cohesive energy density), it has been suggested that nanocellulose might act as a barrier material.[25][31][32] Although the number of reported oxygen permeability values are limited, reports attribute high oxygen barrier properties to nanocellulose films. One study reported an oxygen permeability of 0.0006 (cm3 µm)/(m2 day kPa) for a ca. 5 µm thin nanocellulose film at 23 °C and 0% RH.[31] In a related study, a more than 700-fold decrease in oxygen permeability of a polylactide (PLA) film when a nanocellulose layer was added to the PLA surface was reported.[25]

The influence of nanocellulose film density and porosity on film oxygen permeability has recently been explored.[33] Some authors have reported significant porosity in nanocellulose films,[34][28][35] which seems to be in contradiction with high oxygen barrier properties, whereas Aulin et al.[31] measured a nanocellulose film density close to density of crystalline cellulose (cellulose Iß crystal structure, 1.63 g/cm3)[36] indicating a very dense film with a porosity close to zero.

Changing the surface functionality of the cellulose nanoparticle can also affect the permeability of nanocellulose films. Films constituted of negatively charged cellulose nanowhiskers could effectively reduce permeation of negatively charged ions, while leaving neutral ions virtually unaffected. Positively charged ions were found to accumulate in the membrane.[37]

Multi-Parametric Surface Plasmon Resonance is one of the methods to study barrier properties of natural, modified or coated nanocellulose. The different antifouling, moisture, solvent, antimicrobial barrier formulation quality can be measured on the nanoscale. The adsorption kinetics as well as the degree of swelling can be measured in real-time and label-free.[38][39]

Foams

Nanocellulose can also be used to make aerogels/foams, either homogeneously or in composite formulations. Nanocellulose-based foams are being studied for packaging applications in order to replace polystyrene-based foams. Svagan et al. showed that nanocellulose has the ability to reinforce starch foams by using a freeze-drying technique.[40] The advantage of using nanocellulose instead of wood-based pulp fibers is that the nanofibrils can reinforce the thin cells in the starch foam. Moreover, it is possible to prepare pure nanocellulose aerogels applying various freeze-drying and super critical CO
2 drying techniques. Aerogels and foams can be used as porous templates.[41][42] Tough ultra-high porosity foams prepared from cellulose I nanofibril suspensions were studied by Sehaqui et al. a wide range of mechanical properties including compression was obtained by controlling density and nanofibril interaction in the foams.[43] Cellulose nanowhiskers could also be made to gel in water under low power sonication giving rise to aerogels with the highest reported surface area (>600m2/g) and lowest shrinkage during drying (6.5%) of cellulose aerogels.[42] In another study by Aulin et al.,[44] the formation of structured porous aerogels of nanocellulose by freeze-drying was demonstrated. The density and surface texture of the aerogels was tuned by selecting the concentration of the nanocellulose dispersions before freeze-drying. Chemical vapour deposition of a fluorinated silane was used to uniformly coat the aerogel to tune their wetting properties towards non-polar liquids/oils. The authors demonstrated that it is possible to switch the wettability behaviour of the cellulose surfaces between super-wetting and super-repellent, using different scales of roughness and porosity created by the freeze-drying technique and change of concentration of the nanocellulose dispersion. Structured porous cellulose foams can however also be obtained by utilizing the freeze-drying technique on cellulose generated by Gluconobacter strains of bacteria, which bio-synthesize open porous networks of cellulose fibers with relatively large amounts of nanofibrils dispersed inside. Olsson et al.[45] demonstrated that these networks can be further impregnated with metalhydroxide/oxide precursors, which can readily be transformed into grafted magnetic nanoparticles along the cellulose nanofibers. The magnetic cellulose foam may allow for a number of novel applications of nanocellulose and the first remotely actuated magnetic super sponges absorbing 1 gram of water within a 60 mg cellulose aerogel foam were reported. Notably, these highly porous foams (>98% air) can be compressed into strong magnetic nanopapers, which may find use as functional membranes in various applications.

Surface modification

The surface modification of nanocellulose is currently receiving a large amount of attention.[46] Nanocellulose displays a high concentration of hydroxyl groups at the surface which can be reacted. However, hydrogen bonding strongly affects the reactivity of the surface hydroxyl groups. In addition, impurities at the surface of nanocellulose such as glucosidic and lignin fragments need to be removed before surface modification to obtain acceptable reproducibility between different batches.[47]

Safety aspects

Health, safety and environmental aspects of nanocellulose have been recently evaluated. Processing of nanocellulose does not cause significant exposure to fine particles during friction grinding or spray drying. No evidence of inflammatory effects or cytotoxicity on mouse or human macrophages can be observed after exposure to nanocellulose. The results of toxicity studies suggest that nanocellulose is not cytotoxic and does not cause any effects on inflammatory system in macrophages. In addition, nanocellulose is not acutely toxic to Vibrio fischeri in environmentally relevant concentrations.[48]

Applications

The properties of nanocellulose (e.g. mechanical properties, film-forming properties, viscosity etc.) makes it an interesting material for many applications and the potential for a multibillion-dollar industry.[49]

Paper and paperboard

Nanocellulose recycling chart[50]
GaAs electronics on nanocellulose substrate[51]
Bendable solar cell on nanocellulose substrate

There is potential of nanocellulose applications in the area of paper and paperboard manufacture. Nanocelluloses are expected to enhance the fiber-fiber bond strength and, hence, have a strong reinforcement effect on paper materials.[52][53][54] Nanocellulose may be useful as a barrier in grease-proof type of papers and as a wet-end additive to enhance retention, dry and wet strength in commodity type of paper and board products.[55][56][57][58] It has been shown that applying CNF as a coating material on the surface of paper and paperboard improves the barrier properties, especially air resistance. It also enhances the structure properties of paperboards (smoother surface).[59]

Nanocellulose can be used to prepare flexible and optically transparent paper. Such paper is an attractive substrate for electronic devices because it is recyclable, compatible with biological objects, and easily degrades when disposed of.[51]

Like resin-free lignocellulose fiberboard which are produced using wet process, high tough cellulose nanofiber board with thickness of 3 mm was also introduced by Yousefi et al., 2018.

Composite

As described above the properties of the nanocellulose makes an interesting material for reinforcing plastics. Nanocellulose has been reported to improve the mechanical properties of, for example, thermosetting resins, starch-based matrixes, soy protein, rubber latex, poly(lactide). The composite applications may be for use as coatings and films,[60] paints, foams, packaging.

Food

Nanocellulose can be used as a low calorie replacement for today’s carbohydrate additives used as thickeners, flavour carriers and suspension stabilizers in a wide variety of food products and is useful for producing fillings, crushes, chips, wafers, soups, gravies, puddings etc. The food applications were early recognised as a highly interesting application field for nanocellulose due to the rheological behaviour of the nanocellulose gel.

Hygiene and absorbent products

Applications in this field include: Super water absorbent material (e.g. for incontinence pads material), nanocellulose used together with super absorbent polymers, nanocellulose in tissue, non-woven products or absorbent structures and as antimicrobial films. [citation needed]

Emulsion and dispersion

Nanocellulose has numerous applications as a food additive, and in the general area of emulsion and dispersion applications in other fields.[61][62] Oil in water applications were early recognized. Early investigators had explored the area of non-settling suspensions for pumping sand, coal as well as paints and drilling muds.[citation needed]

Oil recovery

Hydrocarbon fracturing of oil-bearing formations is a potentially interesting and large-scale application. Nanocellulose has been suggested for use in oil recovery applications as a fracturing fluid. Drilling muds based on nanocellulose have also been suggested.[citation needed]

Medical, cosmetic and pharmaceutical

The use of nanocellulose in cosmetics and pharmaceuticals was also early recognized. A wide range of high-end applications have been suggested:

  • Freeze-dried nanocellulose aerogels used in sanitary napkins, tampons, diapers or as wound dressing
  • The use of nanocellulose as a composite coating agent in cosmetics e.g. for hair, eyelashes, eyebrows or nails
  • A dry solid nanocellulose composition in the form of tablets for treating intestinal disorders
  • Nanocellulose films for screening of biological compounds and nucleic acids encoding a biological compound
  • Filter medium partly based on nanocellulose for leukocyte free blood transfusion
  • A buccodental formulation, comprising nanocellulose and a polyhydroxylated organic compound
  • Powdered nanocellulose has also been suggested as an excipient in pharmaceutical compositions
  • Nanocellulose in compositions of a photoreactive noxious substance purging agent
  • Elastic cryo-structured gels for potential biomedical and biotechnological application.[63]
  • Matrix for 3D cell culture

Other applications

  • As a highly scattering material for ultra-white coatings.[64]
  • Activate the dissolution of cellulose in different solvents
  • Regenerated cellulose products, such as fibers films, cellulose derivatives
  • Tobacco filter additive
  • Organometallic modified nanocellulose in battery separators
  • Reinforcement of conductive materials
  • Loud-speaker membranes
  • High-flux membranes
  • Computer components[29][65]
  • Capacitors[66]
  • Lightweight body armour and ballistic glass[29]
  • Corrosion inhibitors[67]

Commercial production

Although wood-driven nanocellulose was first produced in 1983 by Herrick and Turbak, its commercial production postponed till 2010, mainly due to the high production energy consumption and high production cost. Inventia Co. in Sweden was the first nanocellulose company established in 2010. Other first-generation active companies include CelluForce (Canada), Kruger (Canada), Performance BioFilaments (Canada), Nippon (Japan), Nano Novin Polymer Co. (Iran), Maine University (USA), VTT (Finland), Sappi (Netherlands), InoFib (France), and Melodea (Israel). The largest MFC production unit in the world is located at Stora Enzo's production facilities located at it's mill in Imatra Finland.

See also

References

{{Reflist|colwidth=30em|refs=

  1. ^ Peng BL, Dhar N, Liu HL, Tam KC (2011). "Chemistry and applications of nanocrystalline cellulose and its derivatives: A nanotechnology perspective" (PDF). The Canadian Journal of Chemical Engineering. 89 (5): 1191–1206. doi:10.1002/cjce.20554. Archived from the original (PDF) on 2016-10-24. Retrieved 2012-08-28. {{cite journal}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
  2. ^ Cite error: The named reference Turbak1983 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Herrick1983 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Turbak, A, F., Snyder, F.W. and Sandberg, K.R. was invoked but never defined (see the help page).
  5. ^ Turbak, A.F., Snyder, F.W. and Sandberg, K.R. (1984) "Microfibrillated Cellulose—A New Composition of Commercial Significance," 1984 Nonwovens Symposium, Myrtle Beach, SC, Apr. 16–19. TAPPI Press, Atlanta, GA. pp 115–124.
  6. ^ Cite error: The named reference Berglund2005 was invoked but never defined (see the help page).
  7. ^ "Ultrasonic Production of Nano-Structured Cellulose". hielscher.com. Retrieved 27 January 2015.
  8. ^ a b c d e Cite error: The named reference Paakko2007 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Wagberg2008 was invoked but never defined (see the help page).
  10. ^ "Marcus Wallenberg Prize: 2015 – Akira Isogai, Tsuguyuki Saito, Japan, and Yoshiharu Nishiyama, France". http://mwp.org/. Retrieved 23 January 2018. {{cite web}}: External link in |publisher= (help)
  11. ^ Cite error: The named reference Lindstrom2009 was invoked but never defined (see the help page).
  12. ^ Sharma, P.R.; Joshi,R.; Sunil K.,S.; Benjamin S.,H. (2017). "A Simple Approach to Prepare Carboxycellulose Nanofibers from Untreated Biomass". Biomacromolecules. 18 (8): 2333–2342. doi:10.1007/s10570-0. {{cite journal}}: Cite has empty unknown parameters: |1= and |2= (help)
  13. ^ Sharma, P.R.; Zheng,B.; Sunil K.,S.; Zhan C.; Wang R.; Bhatia S.,R.; Benjamin S.,H. (2018). "High Aspect Ratio Carboxycellulose Nanofibers Prepared by Nitro-Oxidation Method and Their Nanopaper Properties". ACS Appl. Nano Mater. 1 (8): 3969–3980. doi:10.1021/acsanm.8b00744. {{cite journal}}: Cite has empty unknown parameters: |1=, |2=, |3=, |4=, and |5= (help)
  14. ^ Sharma, P.R.; Chattopadhyay,A.; Sunil K., S.; Lihong G.,S.; Benjamin S.,H. (2018). "Lead removal from water using carboxycellulose nanofibers prepared by nitro-oxidation method". Cellulose. 25 (3): 1961–1973. doi:10.1007/s10570-018-1659-9). {{cite journal}}: Cite has empty unknown parameters: |1=, |2=, and |3= (help)
  15. ^ Sharma, P.R.; Chattopadhyay, A.; Sunil K., S.; Lihong G., S.; Nasim A.; Darren M.; Benjamin S., H. (2018). "Nanocellulose from Spinifex as an Effective Adsorbent to Remove Cadmium(II) from Water". ACS Sustainable Chem. Eng. 6 (3): 3279–3290. doi:10.1021/acssuschemeng.7b03473). {{cite journal}}: Cite has empty unknown parameters: |1=, |2=, |3=, |4=, and |5= (help)
  16. ^ Sharma, P.R.; Chattopadhyay, A.; Sunil K., S.; Benjamin S., H. (2017). "Efficient Removal of UO22+ from Water Using Carboxycellulose Nanofibers Prepared by the Nitro-Oxidation Method". Industrial & Engineering Chemistry Research. 56 (46): 13885–13893. doi:10.1021/acs.iecr.7b03659). {{cite journal}}: Cite has empty unknown parameters: |1= and |2= (help)
  17. ^ Sharma, P.R.; Verma, A.J. (2013). "Functional nanoparticles obtained from cellulose: engineering the shape and size of 6-carboxycellulose". Chemical Communications. 49: 13885–13893. doi:10.1039/C3CC44551H). {{cite journal}}: Cite has empty unknown parameter: |1= (help)
  18. ^ "Engineering Algae to Make the 'Wonder Material' Nanocellulose for Biofuels and More". newswise.com.
  19. ^ "Nanocellulose - NaNo Research GROUP @ ICAR-CIRCOT, Mumbai".
  20. ^ Cite error: The named reference Siro2010 was invoked but never defined (see the help page).
  21. ^ Chinga-Carrasco, G.; Yu, Y.; Diserud, O. (21 July 2011). "Quantitative Electron Microscopy of Cellulose Nanofibril Structures from Eucalyptus and Pinus radiata Kraft Pulp Fibers". Microscopy and Microanalysis. 17 (4): 563–571. Bibcode:2011MiMic..17..563C. doi:10.1017/S1431927611000444. PMID 21740618.
  22. ^ Chinga-Carrasco G, Miettinen A, Luengo Hendriks CL, Gamstedt EK, Kataja M (2011). Structural Characterisation of Kraft Pulp Fibres and Their Nanofibrillated Materials for Biodegradable Composite Applications. InTech. ISBN 978-953-307-352-1.
  23. ^ Chinga-Carrasco, G. (13 June 2011). "Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view". Nanoscale Research Letters. 6 (1): 417. Bibcode:2011NRL.....6..417C. doi:10.1186/1556-276X-6-417. PMC 3211513. PMID 21711944.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  24. ^ Li, Qingqing; Scott Renneckar (6 January 2011). "Supramolecular Structure Characterization of Molecularly Thin Cellulose I Nanoparticles". Biomacromolecules. 12 (3): 650–659. doi:10.1021/bm101315y. PMID 21210665.
  25. ^ a b c Cite error: The named reference Fukuzumi2009 was invoked but never defined (see the help page).
  26. ^ a b c Cite error: The named reference Aulin2009 was invoked but never defined (see the help page).
  27. ^ a b Cite error: The named reference tatsumi2002 was invoked but never defined (see the help page).
  28. ^ a b Cite error: The named reference Henriksson2008 was invoked but never defined (see the help page).
  29. ^ a b c "Why wood pulp is world's new wonder material – tech – 23 August 2012". New Scientist. Retrieved 2012-08-30.
  30. ^ Cite error: The named reference Mittal2018 was invoked but never defined (see the help page).
  31. ^ a b c Cite error: The named reference Aulin2010a was invoked but never defined (see the help page).
  32. ^ Cite error: The named reference Syverud2009 was invoked but never defined (see the help page).
  33. ^ Chinga-Carrasco, G.; Syverud K. (19 March 2012). "On the structure and oxygen transmission rate of biodegradable cellulose nanobarriers". Nanoscale Research Letters. 7 (1): 192. Bibcode:2012NRL.....7..192C. doi:10.1186/1556-276X-7-192. PMC 3324384. PMID 22429336.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  34. ^ Cite error: The named reference Henriksson2007 was invoked but never defined (see the help page).
  35. ^ Cite error: The named reference Svagan2007 was invoked but never defined (see the help page).
  36. ^ Cite error: The named reference Diddens2008 was invoked but never defined (see the help page).
  37. ^ Cite error: The named reference permselective2009 was invoked but never defined (see the help page).
  38. ^ Mohan, Tamilselvan; Niegelhell, Katrin; Zarth, Cíntia Salomão Pinto; Kargl, Rupert; Köstler, Stefan; Ribitsch, Volker; Heinze, Thomas; Spirk, Stefan; Stana-Kleinschek, Karin (10 November 2014). "Triggering Protein Adsorption on Tailored Cationic Cellulose Surfaces". Biomacromolecules. 15 (11): 3931–3941. doi:10.1021/bm500997s. PMID 25233035.
  39. ^ Vuoriluoto, Maija; Orelma, Hannes; Johansson, Leena-Sisko; Zhu, Baolei; Poutanen, Mikko; Walther, Andreas; Laine, Janne; Rojas, Orlando J. (2015). "Effect of Molecular Architecture of PDMAEMA–POEGMA Random and Block Copolymers on Their Adsorption on Regenerated and Anionic Nanocelluloses and Evidence of Interfacial Water Expulsion". The Journal of Physical Chemistry B. 119 (49): 5275–15286. doi:10.1021/acs.jpcb.5b07628. PMID 26560798.
  40. ^ Cite error: The named reference Svagan2008 was invoked but never defined (see the help page).
  41. ^ Cite error: The named reference Paako2008 was invoked but never defined (see the help page).
  42. ^ a b Cite error: The named reference Heath2010 was invoked but never defined (see the help page).
  43. ^ Cite error: The named reference Sehaqui2010 was invoked but never defined (see the help page).
  44. ^ Cite error: The named reference Aulin2010b was invoked but never defined (see the help page).
  45. ^ Olsson, R. T.; Azizi Samir, M. A. S.; Salazar-Alvarez, G.; Belova, L.; Ström, V.; Berglund, L. A.; Ikkala, O.; Nogués, J.; Gedde, U. W. (2010). "Making flexible magnetic aerogels and stiff magnetic nanopaper using cellulose nanofibrils as templates". Nature Nanotechnology. 5 (8): 584–8. Bibcode:2010NatNa...5..584O. doi:10.1038/nnano.2010.155. PMID 20676090.
  46. ^ Cite error: The named reference Eichhorn review 2010 was invoked but never defined (see the help page).
  47. ^ Cite error: The named reference Labet2011 was invoked but never defined (see the help page).
  48. ^ Cite error: The named reference Vartiainen2011 was invoked but never defined (see the help page).
  49. ^ Brown, Elvie E.; Hu, Dehong; Abu Lail, Nehal; Zhang, Xiao (2013). "Potential of Nanocrystalline Cellulose–Fibrin Nanocomposites for Artificial Vascular Graft Applications". Biomacromolecules. 14 (4): 1063–71. doi:10.1021/bm3019467. PMID 23421631.
  50. ^ Li, Shaohui; Lee, Pooi See (2017). "Development and applications of transparent conductive nanocellulose paper". Science and Technology of Advanced Materials. 18 (1): 620–633. doi:10.1080/14686996.2017.1364976. PMC 5613913. PMID 28970870.
  51. ^ a b Jung, Yei Hwan; Chang, Tzu-Hsuan; Zhang, Huilong; Yao, Chunhua; Zheng, Qifeng; Yang, Vina W.; Mi, Hongyi; Kim, Munho; Cho, Sang June; Park, Dong-Wook; Jiang, Hao; Lee, Juhwan; Qiu, Yijie; Zhou, Weidong; Cai, Zhiyong; Gong, Shaoqin; Ma, Zhenqiang (2015). "High-performance green flexible electronics based on biodegradable cellulose nanofibril paper". Nature Communications. 6: 7170. Bibcode:2015NatCo...6E7170J. doi:10.1038/ncomms8170. PMC 4455139. PMID 26006731.
  52. ^ Taipale, T.; Österberg, M.; Nykänen, A.; Ruokolainen, J.; Laine, J. (2010). "Effect of microfibrillated cellulose and fines on the drainage of kraft pulp suspension and paper strength". Cellulose. 17 (5): 1005–1020. doi:10.1007/s10570-010-9431-9.
  53. ^ Eriksen, Ø.; Syverud, K.; Gregersen, Ø. W. (2008). "The use of microfibrillated cellulose produced from kraft pulp as strength enhancer in TMP paper". Nord. Pulp Pap. Res. J. 23 (3): 299–304. doi:10.3183/npprj-2008-23-03-p299-304.
  54. ^ Ahola, S.; Österberg, M.; Laine, J. (2007). "Cellulose nanofibrils—adsorption with poly(amideamine) epichlorohydrin studied by QCM-D and application as a paper strength additive". Cellulose. 15 (2): 303–314. doi:10.1007/s10570-007-9167-3.
  55. ^ Syverud, K.; Stenius, P. (2008). "Strength and barrier properties of MFC films". Cellulose. 16: 75–85. doi:10.1007/s10570-008-9244-2.
  56. ^ Aulin, C.; Gällstedt, M.; Lindström, T. (2010). "Oxygen and oil barrier properties of microfibrillated cellulose films and coatings". Cellulose. 17 (3): 559–574. doi:10.1007/s10570-009-9393-y.
  57. ^ Lavoine, N.; Desloges, I.; Dufresne, A.; Bras, J. (2012). "Microfibrillated cellulose - its barrier properties and applications in cellulosic materials: a review". Carbohydr. Polym. 90 (2): 735–64. doi:10.1016/j.carbpol.2012.05.026. PMID 22839998.
  58. ^ Missoum, K.; Martoïa, F.; Belgacem, M. N.; Bras, J. (2013). "Effect of chemically modified nanofibrillated cellulose addition on the properties of fiber-based materials". Ind. Crops Prod. 48: 98–105. doi:10.1016/j.indcrop.2013.04.013.
  59. ^ Mazhari Mousavi, Seyyed Mohammad; et al. (2016). "Cellulose nanofibers with higher solid content as a coating material to improve the structure and barrier properties of paperboard". TAPPI Conference Proceedings: 1–7.
  60. ^ Gamelas, José António Ferreira; Ferraz, Eduardo (2015-08-05). "Composite Films Based on Nanocellulose and Nanoclay Minerals as High Strength Materials with Gas Barrier Capabilities: Key Points and Challenges". BioResources. 10 (4): 6310–6313. doi:10.15376/biores.10.4.6310-6313. ISSN 1930-2126.
  61. ^ Xhanari, K.; Syverud, K.; Stenius, P. (2011). "Emulsions stabilized by microfibrillated cellulose: the effect of hydrophobization, concentration and o/w ratio". Dispersion Science and Technology. 32 (3): 447–452. doi:10.1080/01932691003658942.
  62. ^ Lif, A.; Stenstad, P.; Syverud, K.; Nydén, M.; Holmberg, K. (2010). "Fischer-Tropsch diesel emulsions stabilised by microfibrillated cellulose". Colloid and Interface Science. 352 (2): 585–592. Bibcode:2010JCIS..352..585L. doi:10.1016/j.jcis.2010.08.052. PMID 20864117.
  63. ^ Syverud, K.; Kirsebom, H.; Hajizadeh, S.; Chinga-Carrasco, G. (12 December 2011). "Cross-linking cellulose nanofibrils for potential elastic cryo-structured gels". Nanoscale Research Letters. 6 (1): 626. Bibcode:2011NRL.....6..626S. doi:10.1186/1556-276X-6-626. PMC 3260332. PMID 22152032.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  64. ^ Toivonen, Matti S.; Onelli, Olimpia D.; Jacucci, Gianni; Lovikka, Ville; Rojas, Orlando J.; Ikkala, Olli; Vignolini, Silvia (13 March 2018). "Anomalous-Diffusion-Assisted Brightness in White Cellulose Nanofibril Membranes". Advanced Materials. 30 (16): 1704050. doi:10.1002/adma.201704050. PMID 29532967.
  65. ^ A1 WO application 2016174104 A1, Thomas Dandekar, "Modified bacterial nanocellulose and its uses in chip cards and medicine", published 2016-11-03, assigned to Julius-Maximilians-Universität Würzburg 
  66. ^ Nyström, Gustav; Marais, Andrew; Karabulut, Erdem; Wågberg, Lars; Cui, Yi; Hamedi, Mahiar M. (2015). "Self-assembled three-dimensional and compressible interdigitated thin-film supercapacitors and batteries". Nature Communications. 6: 7259. Bibcode:2015NatCo...6E7259N. doi:10.1038/ncomms8259. ISSN 2041-1723. PMC 4458871. PMID 26021485.
  67. ^ Garner, A. (2015-2016) U.S. patent 9,222,174 "Corrosion inhibitor comprising cellulose nanocrystals and cellulose nanocrystals in combination with a corrosion inhibitor" and U.S. patent 9,359,678 "Use of charged cellulose nanocrystals for corrosion inhibition and a corrosion inhibiting composition comprising the same".
Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=User:*LauRy893/sandbox&oldid=904462963"