introducing natural nanomaterials - kristina oksman
DESCRIPTION
Tonal Innovation Center (TONIC) hosted the second annual International Musical Instruments Seminar in Joensuu, Finland on 14th September- 16th September 2011.TRANSCRIPT
Introduction to Natural Nanomaterials
Kristiina Oksman Niska
Wood and Bionanocomposites
Composite Center Sweden
Luleå University of Technology
The 2nd International Musical Instruments Seminar, 14-16 September 2011, Joensuu, Finland
Introduction Nanomaterials from biomass Separation processes Properties Preparation of nanocomposites Examples of nanocomposites and
other nanomaterials based on cellulose Conclusions
Outline
Nanocellulosic materials– Nanofibers/fibrils– Nanocrystals/whiskers– <100 nm in one
dimension Nanocomposites
– Polymer where the nano-sized cellulose is used to improve the properties
Nanocelluloses and nanocomposites
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Cellulose nanocomposites/nanofib*/nanowhiskers/nanocrystals/microfib*
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Cavaille et al Grenoble, FranceNanocrystals & composites
Research on nanocellulose materials and composites: 1995-2011 ( ISI Web of Sci. Sept 2011)
Taniguchi and Okamora, Niigata, JapanMicrofibrillated Cellulose
Glasser, Virginia Tech, USAWinter et al, Suracuse, USANanocrystals and composites
Yano et al, Kyoto, Japan, Zimmermann et al EMPA, SwitzerlandOksman et al NTNU, NorwaySimonsen et al, Oregon, USASain et al, UofT, Canada
Research interests are focussed on Raw materials sources & separation Large scale / pilot scale production methods Chemical modifications Properties Composite materials development Modelling Assembling of organized structures Product design
Increased industrial interest to use agro or forest based nanomaterials
Activities today
Cellu Comp, Carrot Stix™ www.cellucomp.com
H Yano, Kyoto, Japan
Sport goods: With over 50,000 Carrot Stix rods sold during 2009, the Carrot Stix was the best-selling product in its price category (Nanopatents and Innovations March 2010)
Hierarchical structure of wood
Soft wood fiber, diam 20-30 mm, length 2-5 mm Nanofibers, diam <100 nm, length > mm Crystallites, width < 5 nm, length < 300 nm Mechanical properties increases with decreased size Softwood = E-modulus about 12 GPa and strength
100 MPa Wood nanocrystals = E-modulus about 140 GPa and
strength 10000 MPa
Examples of nanofibers and nanocrystals
Cellulose nanofibersCellulose nanocrystals Bacterial cellulose Collagen nanofibrils
Cellulose crystals/whiskers originate from wood, plants or crops, width ~ 5 nm, length >200 nm depending on the source
Cellulose nanofibers originate from wood, plants, crops or bacteria width below 100 nm, length up to µm scale
Collagen fibrils orginate from animal sources, width 50-500 nm length up to mm scale
Nanosize?
Water molecule < 1 nm
Bacteria ~1,000 nmBlood cells ~ 6,000 nm
Kristiina ~1,550,000,000 nm
Width of a strand of hair ~ 100,000 nmAnts ~ 6,000,000 nm
1 nm
1 m
1 mm
1 μm
Nanometer scale
gettyimages® / www.eas.int / www.cabrillo.edu
Separation of nanocelluloses:Nanofibers and nanocrystals
Mechanical treatments Ultra fine grinding High pressure
homogenizing Ultra sonication Cryo crushing
Chemical treatments Acid hydrolysis Enzymatic treatment
Mechanical vs chemical treatmentCellulose nanofibers from saw dust
Highly coiled and entangled fibers: Ø 10-20 nm, L microns
Straight and rigid units: Ø 1.5-3 nm, L microns
Mechanical separation of nanofibers
Soaking in water and mixing
Fiber suspensionRefining (grinding) Is
olati
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roce
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Repeated until gel formation
Wood
Bleaching (Chlorite )
Purifi
catio
n
Pretreaments(Tempo, Enzymes)
Nanofiber suspension
Cellulose
Nanofibers from biobased resourcesBarley straw Grass straw Oat straw Carrot residueCellulose
500 nm
Ethanol
500 nm
Methanol
Sample preparation for Electron Microscopy
Solvent exchange
Drying
Coating with gold
Dried fibers from water
No coating
Nanopaper preparation
CNF dispersed in water
Vacuum filtration
Hot pressing
Mechanical properties of the nanofiber networks
Nanofiber papers prepared by vacuum filtration and pressing
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E-Modulus (GPa)
Strength (MPa)
Strain at break (%)
Woodfiber 1.3 ± 0.3 16 ± 1 2.4 ± 0.7
Woodnanofiber 11.2 ± 0.8 183 ± 14 5.0 ± 0.9
Residue (sludge)
12.5± 0.4 151 ± 4 2.8 ± 0.6
Carrot 13.3 ± 0.8 204 ± 25 3.1 ± 0.5
Wood, sludge and carrot nanopapers have similar properties Reduced fiber size better network better mech. prop
Isolation of cellulose nanocrystals/whiskers
D. Bondeson, A. Mathew, K. Oksman, Cellulose, 13 (2), 2006, 171-180
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HCL or H2SO4
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Heating
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Sonication
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Centrifugation
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Dialysis
1.H2O
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MCC Cellulose whiskers
200 nm20 m
10 – 15 m
Acid hydrolysis with HCL or H2SO4
amorphous cellulose
crystalline cellulose
100 nmLength: < 300 nm
Width: < 10 nm
Characterization of crystals
Flow birefringence between polarized filters
AFM
Elementary fibrils
Amorphous regions
Crystalline regions
Microcrystalline cellulose: crystalline and amorphous regions
Crystals/whiskers have high crystallinity
XRD before and after separation
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Dimensions measurement using AFM
Tip broadening effect
Sample preparation
1 μm 1 μm
62.2 nm 40.8 mV
Height image Amplitude image
pair Height (nm)
blue 8.776
red 5.402
green 5.171
1 μm
Cellulose nanocrystals from bioresidues
Large scale production of cellulose nanocrystals? We have found that lignin residue from bioethanol production
has a high cellulose content This cellulose can be separated to nanocrystals using only
mechanical processing
Oksman et al, Biomass and Bioenergy 35(2011)146-152
Cellulose based nanocomposites
Cellulose nanofibers or crystals as reinforcements or additives in polymers
Interesting properties−High mechanical properties−High thermal stability−Large surface area −Bio-compatible−Light weight−Optically transparent−High water binding capacity
Nanocomposites and their processing
Films/ sheets Solvent casting For nanofibers and crystals Polymer is dissolved in a solvent,
nanocelluloses are added and the solvent is evaporated
Usually water soluble polymers are used
Thermoset composites Nanopaper sheets are
impregnated with thermoset resin High nanofiber content Good mechanical properties
Melt compounding
Feeding of nanocrystals/fibers in to the extruder is a challenge
Dry feeding Masterbach with high nanocellulose
content Diluted during extrusion
Liquid feeding Fibers/crystals are dispersed
in a liquid Removal liquid Degradation the polymer
Freeze drying and granulation
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Nanocellulose fibers and crystals, thermplastic matrix
Content is low < 5% Industrial process Possible to injection mould
Motor
Feeding
Heating and Mixing
Other possibilities to use nanocellulose
Continuous nanofibers Electrospinning of nanofibers Aligned cellulose fibers Reinforced with nanocrystals Improve fiber properties
Coatings Use nanocellulose to improve
adhesion between fibers and resin
Improve mechanical properties of the laminate, paper etc
Improve barrier properties
Electrospinning of nanofibers
Several nanofibers are spun and collected on the collector
Polymer nanofibers
More possibilities
Aerogels, extremly lightweight materials Aerogels are solid materials with a
density as low as 2 mg/cm3
Both whiskers and nanofibers Freeze and supercritical CO2 drying
Colored thin films Nanowhiskers Self-assembling Surface structure
Araki J; Wada M; Kuga S; Okano T. Langmuir 2000, 16, 2413
Cranston E and Gray D, Biomacromolecules 7 (2006) 2522
Cellulose nanocomposites for medical use
Composites with cellulose nanofibers (Domsjö cellulose)
• Strength 28-40 MPa and strain 20-30% at body temperature and high moisture conditions*
• Biocompatible
*Santis de R, et al. Comp Sci Technol 2004;64:861-871
LTU Dr. AP Mathew (TEM-PLANT EU-project)
Mechanical properties of cellulose-collagen nanocomposites for ligament application
Effect of simulated body conditions and sterilization
SamplesStrength
(MPa)Strain
(%)E-Modulus
(GPa)
Collagen 56.2 ± 12.8 2.7 ± 1.2 3.5 ± 0.7
Cell-Coll 96.2 ± 12.2 1.4 ± 0.5 7.4 ± 0.8
XCell-Coll 186.2 ± 34.2 2.4 ± 0.5 14.5 ± 0.7
Cell-Coll (95RH 37°C) 35.1 ± 2.7 28.0 ± 3.1 -
XCell-Coll (95RH 37°C) 42.3 ± 4.7 19.0 ± 4.2 -
Cell-Coll (95RH 37°C)_ste 37.4 ± 3.7 17.4 ±4.7 -
XCell-Coll (95RH 37°C)_ste 57.8 ± 12.7 15.1 ± 4.1 -
Prototypes
Stable in PBS medium (phosphate buffered saline)
NFPD Tubules Braided NFPDBraided XColl-Cell
Possible applications
High-strength spun fibers and textiles Advanced composite materials Films for barrier and other properties Additives for coatings, paints, lacquers and adhesives Optical devices Electronic applications, lightweight batteries Pharmaceuticals and drug delivery Bone and ligament replacements Hydrogels Aerogels Improved paper, packaging applications New building products Additives for food and cosmetics Separation membranes
Some conclusions Increased interest for natural and renewable
nanomaterials Bio based residues can be used for separation
of natural nanomaterials Nanomaterials are separated to nanosize using
chemical/mechanical processing Nanocomposites processing methods are
casting, impregnation, compounding, spinning, freeze and supercritical CO2 drying
Nanomaterials can be used in medical applications, aerogels, nanomembranes coatings, textiles, composites, packaking appl. etc.
Thank you for listening…
Thank my research team for all results and hard work
Yield of the separation process of nanocelluloses
Cellulose content and yield was highest for lignin residue followed by oat straw > carrot residue > barley straw > grass straw
Materials Lignin residue
Oatstraw
Carrotresidue
Barleystraw
Grassstraw
Yield 48% 23% 20% 14% 13%