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Key Lab for Bamboo and Rattan Sci §Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua Fei International Center for Bamboo and Rattan (ICBR) 9th World Bamboo Congress BELGIUM April 10, 2012
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Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

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Page 1: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Are bamboo fibers stronger and stiffer than wood fibers ?

Yan Yu, Ge Wang, Benhua Fei

International Center for Bamboo and Rattan (ICBR)9th World Bamboo Congress BELGIUM

April 10, 2012

Page 2: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

This is ICBR

Welcome to visit us

Page 3: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

1.1. BackgroundBackground

2.2. The RThe R§§D of fiber testing instrumentD of fiber testing instrument

3.3. Mechanical testing of single bamboo Mechanical testing of single bamboo

and wood fibersand wood fibers

4.4. ConclusionsConclusions

ContentsContents

Page 4: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Bamboo is a kind of special and important forest resources:

having a tree-like shape but

belonging to the grass family;

grows much faster than wood. It

can be harvested sustainably on 3 to 5 year rotation;

bamboo can be used to

substitute wood in many aspects;stronger than most tree species, especially in tensile strength;

1. Background

Page 5: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Species Tensile 

strength (MPa)

MOE(GPa)

Hardwood 92.4 (51‐120) 9.6 (7.6‐11.9)

Softwood 77.6(45‐111) 8.6(5.7‐12.3)

Bamboo 140‐230 11‐17

The tensile strength of bamboo is nearly two times of wood.

Specific strength is comparable to that of alloy steel with highest performance: The stiffness of bamboo is comparable to that of wood;

Comparison of bamboo and wood in mechanical properties

Note: data on wood adapted from “wood handbook”

Page 6: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Technm Scale

Macro

Tissue

Nano

Cell

cm

Cell wall layer:

nanocomposites with cellulose nanofibers embedded in lignin/hemicellul ose matrix

SingleFiber:

muti-ply structures with alternate thick and thin cell wall layers

Fibe bundles:

fiber bonded to fibers Two phase composite

structure: fiber bundles embedded in ground parenchyma

Mechanical graded material: big variation of fiber bundles distribution across a culm wall

Hierarchical structure of bamboo

Fiber is the key to know bamboo !!!!

Page 7: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

The increasing interests in bamboo fiber reinforced composites (BFRC) need to know more about the mechanical properties of bamboo fibers.

Molded BRFC with medium or high density

Foamed BRFC with super low density

Page 8: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

It is very difficult to measure the mechanicalproperties of single bamboo fibers.

Technical challenges: Fiber gripping ****** Aligning fiber with tension direction****Measurement of cell wall area***

Sources Length (mm) Diameter (m)

Softwood fiber 2‐5  20‐50

Bamboo fiber 1.5‐3 8‐20

Rattan fiber 1‐2 8‐20

Flax fiber 9‐70 5‐38

Hemp fiber 5‐55 10‐50

Jute fiber 2‐5 10‐25

Dimensions of some selected plant fibers

Page 9: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

No commercial instruments are available in the market

Custom-built microtester developed by Groom et al, SRS, USA

Custom-built microtester developed by Burgert et al, Max Plank, Germany

Page 10: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

A overview of SF-Microtester I developed by ICBR

2. The R§D of fiber testing instrument

Page 11: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Main component parts of SF-Microtester I

Environmental chamber for humidity control Microscope in vertical direction

Microscope in horizontal direction

Special fiber grips (Key part)

3 D adjustable stage

Control box

Computer

Page 12: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

The patented special fiber grips fabricated with laser incision

Page 13: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Sample chamber for humidity control

Range of RH control: 30%-95%

Page 14: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Fiber gripping system designed for specific commercial mechanical tester

Page 15: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Fiber gripping systemWith environmental chamber 

Without environmental chamber 

reducing cost Data analysis is much more easierMuch more options for loading control

Page 16: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Bamboo fibers

Bamboo fiber preparation

3. Mechanical testing of single bamboo and wood fibers

Page 17: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

A

B

200 m

0.8 mm

Micro resin droplets formed on fibers with a space about 1 mm

Page 18: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

0.7 mm

Side view

Top view

Resin droplet

Fiber

Fiber installation

Page 19: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

A1 A2

B1

B2

1

0.8 mm0.8 mm

50 m

50 m

Micro-adjustment of fiber orientation before testing

Page 20: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

A=168.4 m2

20 m 20 m

A=133.16 m2

A

B

C

D

Using CLSM to measure the cell wall area of single broken bamboo fibers

Page 21: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

0.00 0.03 0.06 0.09 0.12 0.150

400

800

1200

1600

2000

Stre

ss (M

Pa)

Tensile strain (mm/mm)

Strain-stress curves of single Moso bamboo fibers with ages from 1.5 to 4.5 years

Page 22: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

The tensile elastic modulus of single bamboo fibers from 12 species

C: Neosinocalamus affinis ( Rendle ) Keng f. CG: Bambusa pervariabilis McClureS: Phyllostachys heteroclada Oliver YS: Bambusa multiplex cv. ‘Sliverstripe’QS: Bambusa eutuldoides var. viridi-vittata ( W.T.Lin ) ChiaDS: Dendrocalamopisis .vario-striata ( W.T.Lin ) Keng f. HM: Bambusa longispiculata Gamble ex BrandisH: Bambusa albo-lingata Chia FD: Bambusa chungii McClureLV: Dendrocalamopisis oldhami ( Munro ) Keng f. Ma: Dendrocalamus latiflorus MunroM: Phyllostachys heterocycla ( Carr. )

Page 23: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

The tensile strength of single bamboo fibers from 12 species

C: Neosinocalamus affinis ( Rendle ) Keng f. CG: Bambusa pervariabilis McClureS: Phyllostachys heteroclada Oliver YS: Bambusa multiplex cv. ‘Sliverstripe’QS: Bambusa eutuldoides var. viridi-vittata ( W.T.Lin ) ChiaDS: Dendrocalamopisis .vario-striata ( W.T.Lin ) Keng f. HM: Bambusa longispiculata Gamble ex BrandisH: Bambusa albo-lingata Chia FD: Bambusa chungii McClureLV: Dendrocalamopisis oldhami ( Munro ) Keng f. Ma: Dendrocalamus latiflorus MunroM: Phyllostachys heterocycla ( Carr. )

Page 24: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

F M0

10

20

30

40

Tens

ile M

odul

us (

GPa

)

 

F M0.0

0.5

1.0

1.5

2.0

Tens

ile S

treng

th (

GPa

)The tensile elastic modulus and strength of two kinds of softwood fibers

F:Cunninghamia lanceolata(Lamb.)Hook.M:Pinus massoniana (Lamb.)

Page 25: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Why is mechanical performance of bamboo fibers much better than wood fibers?

Small MFA, about 10 degree

Pits are small (700 nm), distribution is

scarce; high defects tolerance due to

thick cell wall

Page 26: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

The average tensile modulus and strength of bamboo fibers

are both significantly higher than wood fibers, which could be

attributed to the microstructural characteristics of smal l

microfibrillar angle (MFA) and scarcity of pits in bamboo fibers;

Bamboo fibers are promising reinforcements for the

production of high-performance structural fiber/polymer

composites;

The instruments we developed provide valuable approach for

the study of plant short fibers and its composites.

Conclusions

Page 27: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Acknowledgements

Our work is financially supported by the following projects:

‘‘948’’ Project of State Forestry Administration (PI: Wang

Ge, Yu Yan)

National Natural and Science Foundation of China (PI: Fei

Benhua, Yu Yan)

Key Technology R&D Program of 11th Five Years Plan of

China (PI: Yu Yan)

Dr Les Groom is greatly appreciated for his suggestions in the

development of our fiber Microtester.

Page 28: Are bamboo fibers stronger and stiffer than wood … Yu, Ge...Key Lab for Bamboo and Rattan Sci Tech Are bamboo fibers stronger and stiffer than wood fibers ? Yan Yu, Ge Wang, Benhua

Key Lab for Bamboo and Rattan Sci §Tech

Thank you for your attentions!