Israel González Tovar
LEPAMAP Group
University of Girona (Spain)
Content
 The improvement of paper’s strength through refining
 Cellulose nanofibres (definition, sources and production)...
Mechanical refining (beating) is the main
method to improve paper’s strength
Refined fibres present better properties
than normal fibres, however…
What are cellulose nanofibres (CNF)?
Source: Isogai 2010
Why CNF in papermaking?
˃ Compatibility
˃ Large specific surface area (great bonding capacity)
˃ High strength and stiffne...
How do we release the microfibrils?
Chemical pre-treatment (TEMPO-mediated
oxidation)
EXPERIMENTS:
How do we release the microfibrils?
Enzymatic pre-treatment
EXPERIMENTS:
EXPERIMENTS:
TEMPO-mediated
oxidation
(bleached euc pulp)
TEMPO-CNF
(surface
application)
Enz-CNF bulk
application
(1.5, 3...
Sample
Cationic
demand
(µeq·g/g)
Surface
area
(m2
/g)
Diametre
(nm)
Yield
(%)
Transmittance
(800nm, %)
Degree
of polym.
En...
High carboxylic content
Lower polymerization
degree
Shorter nanofibres
TEMPO-oxidized CNF are better for surface applicati...
CNF-reinforced papers show improved strength
RESULTS
Achieved without mechanical refining!!!, preserving fibre’s
original length and properties.
Increase of 273%!!!!
RESULTS
Bulk
(cm3/g)
Opacity
(%)
Gurley Porosity
(s)
1,91 88,6 1,1
1,81 88,2 2,1
1,76 87,6 3,0
1,70 87,0 3,8
Effect of enzymatic C...
Papers become denser after CNF addition (more compact structure)
RESULTS
CNF-reinforced papers present also improved internal cohesion
RESULTS
Costs of CNF production: a
pending task
Type of CNF Pretreatment
Nanofibrillation
Process at 2wt% fiber Total
Cost
(€/kg
C...
CNF are an interesting alternative over mechanical beating.
CNF improve mechanical and physical properties of paper by
i...
Thank you for your attention!!
We’re waiting for your visit in
Girona!!
Girona
of 19

Nanofibrillated cellulose incorporation, in bulk and surface, to papermaking without mechanical refining: Mechanical properties assessment

Israel Gonzalez Tovar, University of Girona (LEPAMAP). This was presented during the New Ideas for the Paper Industry: Young Researchers' Presentations session, organised as part of European Paper Week 2015. More at http://www.cepi.org/epw
Published on: Mar 3, 2016
Published in: Business      
Source: www.slideshare.net


Transcripts - Nanofibrillated cellulose incorporation, in bulk and surface, to papermaking without mechanical refining: Mechanical properties assessment

  • 1. Israel González Tovar LEPAMAP Group University of Girona (Spain)
  • 2. Content  The improvement of paper’s strength through refining  Cellulose nanofibres (definition, sources and production)  Addition of CNF into papermaking suspensions  Experiments  Results  Conclusions
  • 3. Mechanical refining (beating) is the main method to improve paper’s strength
  • 4. Refined fibres present better properties than normal fibres, however…
  • 5. What are cellulose nanofibres (CNF)? Source: Isogai 2010
  • 6. Why CNF in papermaking? ˃ Compatibility ˃ Large specific surface area (great bonding capacity) ˃ High strength and stiffness ˃ Transparency
  • 7. How do we release the microfibrils? Chemical pre-treatment (TEMPO-mediated oxidation) EXPERIMENTS:
  • 8. How do we release the microfibrils? Enzymatic pre-treatment EXPERIMENTS:
  • 9. EXPERIMENTS: TEMPO-mediated oxidation (bleached euc pulp) TEMPO-CNF (surface application) Enz-CNF bulk application (1.5, 3 and 4.5%) Enzymatic treatment (bleached euc pulp) Mechanical and physical characterization Solution A (0.45wt% CNF) Solution B (0.45 wt% CNF+2.5wt% starch size press) Density, porosity, opacity, breaking length, scott bond, burst index Catiotic demand, surface area, yield, transmittance, diametre
  • 10. Sample Cationic demand (µeq·g/g) Surface area (m2 /g) Diametre (nm) Yield (%) Transmittance (800nm, %) Degree of polym. Enzymatic CNF (4 h contact time, 240 g/ton) 258 105.2 23.8 34.0 38.9 307 TEMPO-oxidized CNF (15 mmol HClO, alkaline pH) 1988 323 8.3 >95 84.7 197 Bulk application: non-chemical CNF have lesser impact on pulp’s drainability Surface application: shorter fibres penetrate better into the paper’s structure RESULTS
  • 11. High carboxylic content Lower polymerization degree Shorter nanofibres TEMPO-oxidized CNF are better for surface application because: RESULTS
  • 12. CNF-reinforced papers show improved strength RESULTS
  • 13. Achieved without mechanical refining!!!, preserving fibre’s original length and properties. Increase of 273%!!!! RESULTS
  • 14. Bulk (cm3/g) Opacity (%) Gurley Porosity (s) 1,91 88,6 1,1 1,81 88,2 2,1 1,76 87,6 3,0 1,70 87,0 3,8 Effect of enzymatic CNF on physical properties added in masse to bleached kraft hardwood pulp CNF content Thickness (μm) 0 145,52 1,5 138,64 3 133,88 4,5 129,34 ºSR 15 21 24 29 RESULTS
  • 15. Papers become denser after CNF addition (more compact structure) RESULTS
  • 16. CNF-reinforced papers present also improved internal cohesion RESULTS
  • 17. Costs of CNF production: a pending task Type of CNF Pretreatment Nanofibrillation Process at 2wt% fiber Total Cost (€/kg CNF) Treatment Conditions Chemicals (€/kg CNF) Energy (€/kg CNF) Enzymes (€/kg CNF) Energy consumption (kW·h/kg) Energy cost* (€/kg CNF) Enzymatic hydrolysis T=50ºC, pH=5, 240g/t, 4h and 5wt% fiber 0,01** 0,07 0,48 19,1 1,53 2,09 TEMPO oxidation 15 mmols 303,06** 0,03 0,00 19,1 1,53 304,62 RESULTS
  • 18. CNF are an interesting alternative over mechanical beating. CNF improve mechanical and physical properties of paper by increasing the amount of hydrogen bonds between fibres. CNF can be applied as bulk additives or as coatings. Addition of CNF as bulk and surface additive increase paper’s strength in 273%. TEMPO-oxidized CNF have high fabrication costs in comparison to enzymatic CNF. CONCLUSIONS
  • 19. Thank you for your attention!! We’re waiting for your visit in Girona!! Girona

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