The 1st International Conference on Processing Technologies for the Forest and Bio-based ProductsTechnologies for the Forest and Bio based Products

Industries. Salzburg/Kuchl, Austria, 07-08 October 2010g , ,

BRANCH WOOD,BRANCH WOOD,FROM SECONDARY WOOD FROM SECONDARY WOOD

RESOURCE TO VALUE ADDED ECORESOURCE TO VALUE ADDED ECO--RESOURCE TO VALUE ADDED ECORESOURCE TO VALUE ADDED ECO--PRODUCTSPRODUCTS

Authors:Authors:•Lidia GURAU*• Marina CIONCA

Faculty of Wood Engineering Transilvania University of Brasov

•Cristina TIMAR•Alin OLARESCU

ROMANIA

Why looking at secondary wood resources?Why looking at secondary wood resources?• Massive wood

exploitation majorexploitation -major concern of the near future!future!

• wood-processing i d i li i i h iindustries -limiting their use to the stem

• reduced availability of large-sized trees g

• environmental pressures• Solution: reducing• Solution: reducing

wood waste and finding alternatives to stemalternatives to stem wood From:Hakkila, P.: Utilisation of Residual Forest Biomass.

P l d f t b hP l d f t b hPanels made of crosscut branchesPanels made of crosscut branches

• This idea is not absolutely new, while it was used in the past by craftsmen to p ydecorate very valuable style furniture fronts

chest of drawers panelled with crosscut olive wood, 18th century

How branch panels are made?How branch panels are made?ASSEMBLING MODEL

Gluing the prisms to form a panel

Cutting square prisms, 30 mm to form a panelsection size

Crosscutting strips 20 mm wide

- -Gluing the strips to form l 20 thi k ith

-panels 20 mm thick with transversal grain display

and calibrating facesSizing to length and width

PANELS

Objectives of this paperObjectives of this paperj p pj p p

Thi i i ti ti th MOE d MOR f l• This paper is investigating the MOE and MOR of maplebranch eco-panels with crosscut grain, which arecompared with reference values of other composite panelscompared with reference values of other composite panelstaken from literature

• To compare the results with the characteristics of the raw• To compare the results with the characteristics of the rawmaterial, specimens of branch wood and stem wood ofmaple (Acer platanoides L ) are tested for theirmaple (Acer platanoides L.) are tested for theircompression strength parallel to the grain, MOE andMOR.

• For completeness, SEM and optical microscopy of maplebranch wood and stem wood together with image analysisg g ywith a specialized software are used to interpret theresults.

MethodMethod-- maple branch panelsmaple branch panels• Straight maple (Acer platanoides) branch pieces of app.

500-600 mm and with diameters ranging between 6-10 cm500 600 mm and with diameters ranging between 6 10 cm • Two maple branch panels with crosscut grain were

manufactured from maple branch prisms of 30 x 30 mm asmanufactured from maple branch prisms of 30 x 30 mm as previously shownTh dh i d l i l d h fi l i• The adhesive used was polyvinyl acetate and the final size of the panels was 510 x 270 x 20 mm.

EN 310EN 310

• Out of the two panels, specimens were prepared for testing their MOR and MOE according to EN 310

EN 310MethodMethod-- MOE, MORMOE, MOR--l b h ll b h lmaple branch panelsmaple branch panels

INSTRON 4411 universal testing machine and bending test equipmentmachine and bending test equipment

Mitutoyo digital control cabinet

measuring caliper

450 x 50 x 20 mm

data

450 x 50 x 20 mm

data acquisition system

Acknowledgements are due to FPRC-BCUC-UK

system

MethodMethod-- compression strengthcompression strength--maple branch and stem specimensmaple branch and stem specimensmaple branch and stem specimensmaple branch and stem specimens

Analogue control

Mit t

Analogue control cabinet

Mitutoyo measuring

li Peakcaliper

Di i ISO 3787

Peak load meterDimensions ISO 3787:

60x20x20data

meter reading

data acquisition system

ESH UNIVERSAL

system

ESH UNIVERSAL TESTING MACHINESpecimens were

weighted

MethodMethod-- MOE, MORMOE, MORl b h d tl b h d tmaple branch and stem maple branch and stem

specimensspecimensspecimensspecimensdigital control cabinetBending equipment cabinet

Labtech

g q pas in BS 373

Notebook software

Dimensions as indata acquisition

ISO 313, ISO 3349, BS 373: 300x20x20

qsystem

INSTRON 4411 universal testing hi d b di t t i t

Testing as in EN 310 preferred to ISO 3349(MOE)

machine and bending test equipmentand ISO 313 (MOR)

MethodMethod-- optical microscopyoptical microscopyp pyp py

• To better understand the behaviour of maple pbranch and stem wood specimens subjected to mechanical testing, microslides for each

t f t i lcategory of material were prepared for examination with anexamination with an optical microscope

• Images were taken Optical microscope• Images were taken with magnifications of 40x, 100x, 200x

Optical microscope BIOSTAR OPTECH B5 fitted with an40x, 100x, 200x B5 fitted with an image capture system

MethodMethod-- image analysis with ImageJimage analysis with ImageJThi d f b i i i i l i f h i i d• This was used for obtaining a quantitative evaluation of the investigated parameters.

• ImageJ identifies wood cells (eg. pores) as objects, selects their contour and g ( g p ) jreturns a mask image where only the objects (anatomical cells) of interest are kept

• it provides numerical data about the measured objects such as: area and p jperimeter of each object, total and average area of objects, percentage and number of objects detected in an image.

http://en.wikipedia.org/wiki/ImageJ

MethodMethod-- SEM microscopySEM microscopy

• Separately, small cubes about 3 × 3 × 3 mm ofabout 3 3 3 mm of maple branch and stem wood were prepared andwood were prepared and examined in a Cambridge 150 S i El150 Scanning Electron Microscope using secondary electron imaging. g g

Cambridge 150 Scanning Electron Microscope

ResultsResults-- image image ggprocessingprocessing--ImageJImageJ

MAPLEMAPLE

Values in thebranch wood stem wood

2

Values in the literature include

the cell wallPores/mm2 Mean pores lumen

diameter (µm) Mean area of pores lumen (µm2)

Percentage of total lumen pores area (%)25-50-110 (Wagenfuhr) 4-6,9-8,4%,

30-50 pores/mm2

(Pescarus) (%)B S B S B S B S 61 52 42 43 1260 1429 8.5 7.5

( g ) 4 6,9 8,4%,(Pescarus)

Coefficients of variation (%) in parenthesis; B-branch wood; S-stem wood(6.3) (13.1) (1.6) (2.6) (12.1) (5.3) (6.5) (9.4)

ResultsResults-- SEM micrographsSEM micrographs

Maple-branch wood Maple-stem wood

ResultsResults-- compression strength and compression strength and MORMOR l b h d t dl b h d t dMORMOR-- maple branch and stem woodmaple branch and stem wood

140MPa

120MORMOR

10%

100MORMORD

en De

80nsity

ensit

“shearing”-rupture (as in ASTM, 1997)

More plastic, tends to bend

60 Compression strengthCompression strength

= 68

y = 6

5%40

9 kg/

609 k

5%

0

20

/m3

kg/m3

0Maple branch Maple stem Maple branch Maple stem

3

ResultsResults-- specimen failure in bendingspecimen failure in bendingp gp g

“Simple tension” fail re ASTM 1997“Simple tension” failure-ASTM, 1997.

Branch wood

SEM micrograph of maple branch pwood containing the pith and tissuethe pith and tissuearound it

Stem wood

ResultsResults-- MOEMOE-- maple branch and maple branch and t dt dstem woodstem wood

12000MPa

10000

12000

8000

10000

85%

6000

8000

4000

6000

2000

4000

0

2000

0Maple branch Maple stem

ResultsResults-- comparison of the MOE for comparison of the MOE for ppvarious composite panelsvarious composite panels

8000MPa

7000

8000

5000

6000

4000

5000

2000

3000

1000

2000

11%

0Maple Chipboard MDF OSB Blockboard Softwoodbranchpanel

panels Values for composite panelsfrom Barbu, 1999

ResultsResults-- comparison of the MOR for comparison of the MOR for i it li it lvarious composite panelsvarious composite panels

70MPa

60

70

50

30

40

20

30

10

0Maple Chipboard OSB MDF Blockboard Softwoodbranchpanel

panels

C l iC l iMicroscopMicroscop

ConclusionsConclusions•• MicroscopyMicroscopy

– Compared to maple stem wood maple branch wood contains:• a greater number of pores/mm2g p• a greater proportion of pores• an increased number of medullary rays• an increased number of medullary rays

– The pores lumens in branch wood were approximately h i i d b li h l llthe same size as in stem wood, but slightly smaller

•• DensityDensityyy– Maple branch wood had a higher density than maple

stem woodstem wood

ConclusionsConclusions

•• Mechanical properties Mechanical properties ––raw materialraw material– the MOR of maple branch wood was slightly

higher, while the MOE and compression strength g , p gwere slightly lower than those of the stem wood, which seemed to correlate with the microscopicwhich seemed to correlate with the microscopic characteristics

– Since maple branch wood had similar strengths to maple stem wood this makes likely similar strengths of wood panels with the same orientation.

ConclusionsConclusions•• Mechanical properties Mechanical properties –– maple branch panelsmaple branch panels

– However, branch panels with crosscut grain were oweve , b a c pa e s w t c osscut g a we econsidered for their attractive designTh i i i t ti h d d th i b di– Their grain orientation has reduced their bending performances compared to other composite panels

– The maple branch wood panels had an MOE and MOR app. 50% from those for chipboardapp. 50% from those for chipboard

– This recommends them only for applications where b di t d d h ll d tibending stresses are reduced, such as small decorative eco-products.

BRASOV TRANSYLVANIA ROMANIAE-mail: lidiagurau@unitbv.ro

BRASOV- TRANSYLVANIA-ROMANIA

Comparison between branch panels and stem panels

40

45

Ra processing SANDING WITH P120

35

40 Ra processingRq processingRk processing

25

30

ns

20

25

mic

ron

656

37012 =ρkg/m3

10

1576112 =ρ

kg/m3

65612 =ρkg/m3

kg/m

5

10

0Fir- Branch- Transversal Fir- Branch- Longitudinal Fir- Stem- Longitudinalg g

Fir branch panels Fir stem panels