Biocomposite research at VTT

Antti Ojala

VTT Technical Research Centre of Finland

2 08/04/2015

Biocomposite research at VTT

Competence

The well-equipped laboratory facilities and skilled

personnel enable top-level scientific research and

demanding contract research.

Strategy

International co-operation with customers and research

partners worldwide is the key to successful material

development.

Mission

VTT’s mission is to produce research and innovation

services that enhance the international competitiveness

of the partners in industry in Finland and abroad.

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COMPOSITES

- Biocomposites

- Nanocomposites and nanobiocomposites

- Structural composites (thermoset materials)

THERMOPLASTICS PROCESSING

- Foaming and extrusion technologies

- Nanodispersion for composites

- Non-destructive fibre dispersion

PERFORMANCE PLASTICS

- Flame retardancy

- Thermal and electrical conductivity

- Recyclability

- UV-protection

- Antimicrobial properties

- Barrier properties

- Wear resistance and low friction

Focus areas

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Injection moulding

Thermo-Haake

MiniLab, Micro

Compounder

Tandem Extrusion Foaming Line

Berstorff

Compounding

Line

Plastics processing

Micro-scale melt processing

Small scale processing

Pilot scale processing

Pre- and Post-processing

Injection moulding

Extrusion (profile, cast and blow

film)

Extrusion and particle foaming

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RESEARCH EXAMPLES

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Mechano-chemical fibre

modification

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Mechano-chemical fibre modification

VTT’s own method to modify fibres for composites

Allows addition of reactive additives safely on cellulose surface

Simultaneous additive mixing and fibre compacting for compounding

Low friction even with high dry material content (>70%)

Saves energy and solvent compared to normal solvent processing

methods

Can be used as pre-processing method to enhance enzymatic

modification

Suitable for wood cellulose, saw dust, wood chips, agro fibres etc.

Very high output even with small equipment (180 kg/h)

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Mechano-chemical fibre modification

Used for :

Fibre pulp processing and modification in dry material content up to 40%.

Easy cost and energy saving way to add plasticizers before compounding

Reactive plasticizer addition on fibre surface

Monomer addition for reactive compounding / polymerisation during compounding

Fibre surface modification (fibrillation) for different purposes, fibrillation degree can be adjusted

Pre-processing to enhance enzymatic modification

Pre-processing for cellulose degradation for sugars (improved yield)*

Can be combined with compounding or reactive compounding processes in composite manufacturing

* Patent application WO 2012/113990 A1

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Combined process for fibre modification

and plasticization of PLA

Mechano-chemical cellulose modification method developed at

VTT:

- Is easy, safe, costs, energy and solvent saving method

working with low friction suitable for natural materials

(cellulose, saw dust, agro fibres etc.) even with high dry material

content up to 75%.

- Introduction of additives, their mixing and improved attachments

on fibre

TWO RELATED PATENT APPLICATIONS: 1. Sivonen, E., Valta, K., Seulalevypuristin, Finnish patent application FI20106340 left December 17th 2010.

2. Immonen, K., Sivonen, E., Hulkko, J., Valta, K., Aalto, S., Pitkänen, P., Salorinne, K., Process for manufacturing a thermoformed

plasticized composite containing celulose fiber and a moldable polymer, WO 2012/117165 A2

Results

- Thermoformed sheet materials with PLA and 36% cellulose fibre

content were made

- Tensile strength was improved by 26%

- Impact strength was improved by 100%

Thermoformed sheets

Good connection between

polymer and fibre

Fibre fibrillation

Additional information: Kirsi Immonen

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Example of reactive plasticizers added on birch cellulose

0

5

10

15

20

25

30

35

Birch r

ef.

Lin

ear

OH

Epoxid

e1(B

ranched)

OH

2

Epoxid

e2(e

lasto

mer)

Epoxid

e3(d

i)

Dis

pers

ant1

Epoxid

e4

Anhydride1

Lacto

ne

Anhydride2

Epoxid

e5(S

i)

Dis

pers

ant2

VT

T a

nhydride

VT

T e

poxid

e1

VT

T e

poxid

e2

Imp

act

str

en

gth

, kJ/m

2

Impact strength results for PLA birch pulp composites with 7.5%

additive and a fibre content of 30%

* Related patent applications FI20115218 and FI20106340

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Chemo-enzymatic fibre modification

for biocomposites (EU-WoodWisdom-Net project FunFireBic - Functional Fibre Reinforced Biocomposites)

Enzyme activated functional chemical attachment on fibre surface

Chemo-enzymatically modified lignin containing fibre (e.g. mechanical

fibre) is applicable in the wood fibre-biopolymer biocomposites.

Injection moulded fibre-biopolymer compounds with 40% modified fibre

Better processability and improved fibre dispersion in polymer matrix

e.g. PLA-CTMP composites:

→ 50% increase in tensile strength

→ 130% increase in impact strength

Improved fibre

Dispersion in

PLA and PHB

This modification method is successfully applied also for flax-fibres in

combination with thermosetting epoxy-composites.

Additional information: Anna Suurnäkki or Kirsi Immonen

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Thermoplastic lignin

composites

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Thermoplastic lignin composites FuBio Joint Research 2 (FuBio JR2) project

Lignin: Softwood kraft lignin from Valmet (LignoBoost)

Plasticizers: Biobased plasticiser and polyethylene glycol (PEG)

Fiber: Softwood TMP

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Lignin composites (Fubio JR2)

Lignin composites

Process chain

Cellulose

fibres

Lignin extraction by

Kraft process Plasticisation

Compounding

with fibres

Injection moulding &

extrusion

Lignin Plasticized

lignin

Ojala et al. Thermoplastic lignin and reinforcing cellulose fiber composites for

advanced biocomposite applications, Programme Report 2011-2014, Future

Biorefinery Joint Research 2, 2014.

Ojala et. al. Foam-laid thermoplastic composites based on kraft lignin and softwood

pulp, J. Renew. Mater, 2014, DOI: http://dx.doi.org/10.7569/JRM.2014.634126

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Injection moulded thermoplastic lignin composites

0

5

10

15

20

25

30

0 0,1 0,2 0,3 0,4 0,5 0,6

Ten

sile

str

engt

h /

MP

a

Lignin weight fraction

0

1

2

3

4

5

6

7

0 0,1 0,2 0,3 0,4 0,5 0,6

Mo

du

lus

/ G

Pa

Lignin weight fraction

0

2

4

6

8

10

12

0 0,1 0,2 0,3 0,4 0,5 0,6

Stra

in a

t b

reak

/ %

Lignin weight fraction

0

5

10

15

20

25

0 0,1 0,2 0,3 0,4 0,5 0,6Imp

act

stre

ngt

h /

kJ

/ m

2

Lignin weight fraction

• Composition: kraft lignin / biobased plasticiser / wood fibres

• 20 wt% wood fibre content in all samples

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Thermoplastic lignin composites Biobased plasticiser vs PEG

• 30 wt% TMP fiber content

• Optimized lignin / plasticizer ratios

27

29

5,2 5,9

0,6 0,5 1,7

4,2

Biobased PEG

Tensile Strength (MPa)

Young's modulus (GPa)

Strain at break (%)

Impact Strenght (kJ/m2)

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Water absorption of thermoplastic lignin composites Bio-based plasticiser vs PEG

• 20 wt% TMP reinforcement

• PEG dissolves from the composites

0

10

20

30

40

50

0,0 0,5 1,0 1,5 2,0 2,5

Wei

ght

chan

ge /

%

Time / weeks

Biobased

PEG

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Property PP + Wood1 Lignin + PEG + TMP Lignin + biobased

plasticiser+ TMP

Tensile strength (MPa) 37 29 30

Stiffness (GPa) 3.0 6.5 5.4

Impact strength (kJ/m2) 15 4.4 2.0

1Ichazo et al., Compos. Struct., 2001

Comparison:

40% Wood fibers + PP

vs

30% TMP + lignin + biobased plasticiser

vs

30% TMP + lignin + PEG

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Bicomposite and polymer

foams

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Expanded and extrusion foamed bio-based thermoplastics

Sustainability by replacing oil-based components

Light-weight, high insulation

100% bio-based

Applications in packaging, construction, and transport

Process and development from laboratory to pilot scale

Light weight materials with bio-based foams

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Extrusion Foaming Possibilities at VTT

Thermoplastic foam development from small scale to pilot scale

- Batch foaming equipment: Overall foamability of polymers with various blowing agents (BA’s)

can be evaluated with less than 10 g of sample

- Laboratory scale single screw extrusion foaming line: Extrusion foaming conditions

(temperatures, BA content, etc.) in continuous process can be evaluated with ~2-5 kg of polymer

- Pilot scale tandem extrusion foaming line: Foamed sheet and board can be produced for

industrial testing purposes with ~50-100 kg of polymer

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Extrusion foamed biocomposites

and bio-based thermoplastics

OSIRYS project: Safe, energy-efficient and affordable new eco-innovative materials for

building envelopes and/or partitions to provide a healthier indoor environment

Within the project, VTT develops an interior

multilayer structure from light foam

biocomposite with light-weight, and excellent

mechanical, thermal insulation and sound

absorption and insulation properties

Porous wood fibre webs produced by

foam laid forming

Physically expanded, bio-based closed cell

foam produced by thermoplastic extrusion

process Cell structure of extrusion foamed

biocomposite sample produced in VTT

lab-scale extrusion foaming line

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VTT creates business from technology