Microfibrillated Cellulose Reinforcement in Phenol Formaldehyde Wood AdhesiveWill HandDepartment of Chemical EngineeringAuburn University

Sun Grant Initiative 2015 Sun Grant Regional Conference

Microfibrillated cellulose (MFC)• 3-30 nm

diameter• Wide range

of lengths• Crystalline

and amorphous regions

Why MFC?• Advantages▫ Sustainable, renewable resource▫ High strength and stiffness▫ Transparent and translucent▫ High surface area and aspect ratio▫ High reactivity, barrier properties

Microfluidics

• Hydraulic pump• Interaction chamber (87 µm)• 500 m/s, 330 mL/min @ 30,000 psi• High shear and impact forces

Why MFC?• Disadvantages▫ High energy consumption to process▫ Large water content (1-30% solids content)▫ Hornification▫ Hydrophilic character – compatibility with hydrophobic materials

Methods to improve processing• TEMPO-mediated

oxidation

• Carboxymethylation

• Acetylation

Phenol Formaldehyde• Used as adhesive in production of Oriented Strand Board (OSB)• Disadvantage▫ Formaldehyde off gassing▫ Expensive

• Soy waste▫ Cheap▫ Improves strength

• MFC▫ Past studies show strength improves▫ Synergistic effect

Method• Microfibrillated cellulose (MFC) was mixed with Soy• MFC/Soy mixture was mixed with Phenol Formaldehyde (PF)

adhesive• All pulp and soy mixed with PF was heated or hydrated until

original consistency matched PF (52%)• DIN EN 205 (shear stress) – modified to include MOE

Results – Soy - strength

3020100

11

10

9

8

7

6

5

4

%

T

Soy addition to PF

Preparation of samples• Wood samples were cut according to standard DIN EN

205 from species Pinus taeda 2x4’s into 80 mm x 20 mm x 5 mm pieces

• Adhesive was applied to a 20 mm x 10 mm overlap area• Samples were pressed• Samples were put into oven for 4 hours at 105 °C to cure

20 mm

150mm

10 mm

5mm

5mm

Equipment• Zwick/Roell Z010 Static Material Testing Machine

was used to measure strength and MOE• 9”x9” press was used at 200 psi at different times

and temperatures

Procedure• A lap shear test was conducted on the

Zwick Roell Z010 using the European standard DIN EN 205 for wood adhesives to determine the tensile shear strength of the lap joints

• The testXpert® II software was used to control the machine and analyze the data

Box-Behnken Design• Experimental Design for Response Surface Methodology• Great for costly or timely experiments• Great for not operating at unsafe operating limits

Experimental Design• Response: Strength (N/mm2) and MOE (Gpa)• Factors:▫ MFC/Soy (%) (Low: 0%, Mid: 1%, High: 2%)▫ Press Temperature (°C) (Low: 125°C, Mid: 150°C, High: 175°C)▫ Press Time (minutes) (Low: 7, Mid: 11, High: 15)▫ Loading (g/m2) (Low: 90, Mid: 110, High: 130)

• Optimal conditions for best Strength and MOE while using MFC/soy in PF?

MFC/Soy

Tem

pera

ture

(°C

)

2.00%1.50%1.00%0.50%0.00%

170

160

150

140

130

Time (min) 11Loading (g/m2) 110

Hold Values

> – – – – – – < 6.5

6.5 7.07.0 7.57.5 8.08.0 8.58.5 9.09.0 9.5

9.5

(N/mm2)Strength

Strength Contour plots with temperature and MFC/soy factors

Lower Temperaturesare better

MFC/Soy

Tim

e (m

in)

2.00%1.50%1.00%0.50%0.00%

15

14

13

12

11

10

9

8

7

Temperature (°C) 150Loading (g/m2) 110

Hold Values

> – – – – < 7.00

7.00 7.257.25 7.507.50 7.757.75 8.00

8.00

(N/mm2)Strength

Strength Contour plots with time and MFC/soy factors

Lower press timesare better

MFC/Soy

Load

ing

(g/m

2)

2.00%1.50%1.00%0.50%0.00%

130

120

110

100

90

Temperature (°C) 150Time (min) 11

Hold Values

> – – – – < 7.0

7.0 7.27.2 7.47.4 7.67.6 7.8

7.8

(N/mm2)Strength

Strength Contour plots with loading and MFC/soy factors

1% MFC/Soy performsBest at lower loadings

Temperature (°C)

Tim

e (m

in)

170160150140130

15

14

13

12

11

10

9

8

7

MFC/Soy 0.01Loading (g/m2) 110

Hold Values

> – – – – – < 7.0

7.0 7.57.5 8.08.0 8.58.5 9.09.0 9.5

9.5

(N/mm2)Strength

Strength Contour plots with temperature and time factors

Lower Temperaturesand Times are better

Temperature (°C)

Load

ing

(g/m

2)

170160150140130

130

120

110

100

90

MFC/Soy 0.01Time (min) 11

Hold Values

> – – – – – – < 6.5

6.5 7.07.0 7.57.5 8.08.0 8.58.5 9.09.0 9.5

9.5

(N/mm2)Strength

Strength Contour plots with temperature and loading factors

Lower Temperaturesat lower loadings

are better

Time (min)

Load

ing

(g/m

2)

151413121110987

130

120

110

100

90

MFC/Soy 0.01Temperature (°C) 150

Hold Values

> – – – – – < 7.2

7.2 7.47.4 7.67.6 7.87.8 8.08.0 8.2

8.2

(N/mm2)Strength

Strength Contour plots with loading and time factors

Lower TimesAt lower loadings

are better

Conclusions for Strength• When using MFC/Soy/PF or PF▫ Lower temperatures and press times are optimal

• 1% MFC/Soy maintained strength at lower loadings▫ Less adhesive needed with MFC and soy in PF

• When using lower loadings▫ Lower temperatures and press times are optimal

• Optimum settings are:▫ Low Temperature, press time, and loading

MFC/Soy

Tem

pera

ture

(°C

)

2.00%1.50%1.00%0.50%0.00%

170

160

150

140

130

Time (min) 11Loading (g/m2) 110

Hold Values

> – – – < 3.50

3.50 3.753.75 4.004.00 4.25

4.25

MOE (GPa)

MOE Contour plots with temperature and MFC/soy factors

Lower Temperaturesare better

MFC/Soy

Tim

e (m

in)

2.00%1.50%1.00%0.50%0.00%

15

14

13

12

11

10

9

8

7

Temperature (°C) 150Loading (g/m2) 110

Hold Values

> – – – – – < 3.2

3.2 3.43.4 3.63.6 3.83.8 4.04.0 4.2

4.2

(GPa)MOE

MOE Contour plots with time and MFC/soy factors

Long press time formore MFC/Soy

MFC/Soy

Load

ing

(g/m

2)

2.00%1.50%1.00%0.50%0.00%

130

120

110

100

90

Temperature (°C) 150Time (min) 11

Hold Values

> – – – – < 3.4

3.4 3.53.5 3.63.6 3.73.7 3.8

3.8

(GPa)MOE

MOE Contour plots with loading and MFC/soy factors

Lower loadingsFor more MFC/Soy

Temperature (°C)

Tim

e (m

in)

170160150140130

15

14

13

12

11

10

9

8

7

MFC/Soy 0.01Loading (g/m2) 110

Hold Values

> – – – – < 3.4

3.4 3.63.6 3.83.8 4.04.0 4.2

4.2

(GPa)MOE

MOE Contour plots with temperature and time factors

Lower TemperaturesAnd times are better

Temperature (°C)

Load

ing

(g/m

2)

170160150140130

130

120

110

100

90

MFC/Soy 0.01Time (min) 11

Hold Values

> – – – < 3.4

3.4 3.63.6 3.83.8 4.0

4.0

(GPa)MOE

MOE Contour plots with temperature and loading factors

Lower Temperaturesare better

Time (min)

Load

ing

(g/m

2)

151413121110987

130

120

110

100

90

MFC/Soy 0.01Temperature (°C) 150

Hold Values

> – – – – < 3.3

3.3 3.43.4 3.53.5 3.63.6 3.7

3.7

(GPa)MOE

MOE Contour plots with loading and time factors

Lower Timesare better

Conclusions for Modulus of Elasticity• When using MFC/Soy/PF or PF▫ Lower temperatures are optimal

• When using MFC/PF▫ Longer press times are optimal▫ Lower loadings are optimal

• Optimum settings are:▫ Low Temperature, press time▫ Loading optimum 118 g/m2

Thank you• Dr. Brian K. Via• Dr. W. Robert Ashurst• Dr. Virginia Davis• Dr. Marko Hakovirta• Dr. Sujit Banerjee• Dr. Qingzheng Cheng• Tiffany Ulep