By Nikita Polikarpov, Papiertechnische Stiftung (PTS), 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

1. Reactive extrusion of cellulose fibres as a feasible
way to process value added products
Nikita Polikarpov Brüssel, 17.11.2015

2. 17.11.2015
Sustainable development in paper industry
Paper industry is looking for
• new markets
• new products
• new approaches
Is it possible to imagine…
• Cellulose as a source for bioplastics?
• Cellulose fibres as reinforcement in composites?
• Cellulose fibre as thermoplastic?
Yes, but there are some issues…
• Cellulose esters (bioplastic) are costly.
• Poor interactions between hydrophilic cellulose fibres and hydrophobic thermoplastics.
• Cellulose decomposes below its glass-transition temperature.
2

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PTS Platform Technology Reactive Extrusion
3
Various monomers and
reactive compounds
Pulp
Amorphous cellulose derivatives
Surface modified pulp fibres
(hydrophobic, thermoplastic)
Surface modified
microfibrillated cellulose
• Thermoplastic paper
based products
• Reinforcement in
composites / Light
weight construction
• Masterbatches
• Injection moulding
New
markets /
products
New
approach

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Twin Screw Extruder
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Source: Coperion
Kneading
element
Tooth-mixing
element
Conveying
element
Modular design for screw elements and kneading blocks

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EXAMPLE 1
CELLULOSE ACETYLATION
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Cellulose Acetate
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Dominant thermoplastic cellulose based product is cellulose acetate (~80,000 t/p.a.)
• Properties depend on substitution degree DS and polymerisation degree DP
DS Application
1.8–1.9 Composite fabrics
2.2–2.3 Lacquers, plastics
2.3–2.4 Acetate rayon
2.5–2.6 Safety films
2.8–2.9 Insulation foils
2.9–3.0 Fabrics

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Pulp +
acetic acid
ZSK 26 Mc
Acetic anhydride +
catalyst
Cellulose
acetate
< 1 min reaction time
(compare with 1h
in batch reactor)
Esterification in Extruder

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FTIR – Results of Acetylation
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DS ~3.0
DS 2.4
(commercial product)
DS ~2.2
DS ~0.9
normalisation to band at 1431 cm-1

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Acetylated pulp, DS 0.9–1.6 Cellulose acetate, DS ~3.0NBSK pulp
Pulp Acetylation in Extruder
L(I) c ~ 0.2-0.5 mm L(I) c < 0.05 mm

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Producing Cellulose Triacetate in Extruder
Solvent casting of CTA films

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Producing Acetylated Pulp in Extruder
Hand sheet from acetylated pulp and its thermoplastic properties

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Hand Sheets – Hot Pressing
Cross-sectional SEM image of
thermoplastic paper before hot pressing
Cross-sectional SEM image of
thermoplastic paper upon hot pressing
SEM image of thermoplastic paper upon hot
pressing. Fibre network structure of the non-heated
area (top left) is observable

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EXAMPLE 2
FIBRE BASED MASTERBATCHES
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Pulp
ZSK 26 Mc
Various reactive
modifiers/monomers
Fibre-Polymer
Masterbatches
1-2 min
reaction time
Fibre-Polymer Masterbatches in Extruder

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Fibre-Polymer Masterbatches in Extruder
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O
O
+
kat.
∆
O
O
O
H n
O
O
O
H n
O
O
O
H n
+ PCL

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Before hot pressing Upon hot pressing
Fibre-Polymer Masterbatches for Thermoplastic Paper

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Contact Angle Measurements
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Water drop on a NBSK + PTS-Masterbatch
hand sheet, before hot pressing
Water drop on a NBSK + PTS-Masterbatch
hand sheet, upon hot pressing
~65°
0.5 s
~17°
~56°
0.0 s
0.5 s
0.0 s
1.0 s
~85°
~60°

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Conclusions
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• Reactive extrusion of cellulose fibres is a feasible way to produce cellulose derivatives, fibres
and microfibrillated cellulose with added-value properties
• Example 1. Cellulose acetylation
• Reaction time < 1 min
• Both homogeneous and heterogeneous acetylation was achieved by reactive extrusion
• Various typical for cellulose acetate properties were demonstrated
• Example 2. Fibre-Polymer-Masterbatches
• Potential application as paper additive (thermoplastic and barrier properties)
• Potential application as composite additive (as reinforcement)

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Contact
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Papiertechnische Stiftung, IZP
Dr. Nikita Polikarpov
Pirnaer Str. 37
01809 Heidenau
Telefon: 03529-551-640
nikita.polikarpov@ptspaper.de
http://www.ptspaper.de
Papiertechnische Stiftung, IZP
M.Sc. Tiemo Arndt
Pirnaer Str. 37
01809 Heidenau
Telefon: 03529-551-643
tiemo.arndt@ptspaper.de
http://www.ptspaper.de