Develop Lignin-Protein Based AdhesiveS. Pradyawong, G. Qi, N. Li, X. S. Sun, D. Wang

Biological and Agricultural Engineering Department, Kansas State University, Manhattan, Kansas USA

Future Study

Background

Acknowledgement

Method

Results

1. To improve the wet adhesion strength of protein based adhesive and utilize lignin for value-added product.

2. To study the effect of protein to lignin ratio and lignin particle size on the adhesion performance of soy protein adhesives.

3. To study the rheological, thermal, and adhesion properties of protein and lignin based adhesives.

ObjectivesSource: http://biofueloutlook.blogspot.com Source: http://en.wikipedia.org/wiki/Lignin

• Foundry sand adhesive• Children glue

Soybean adhesive

Properties measurement

Fig. 6. Adhesion test

Lignin

Fig. 1. Wood substrate and protein adhesive adhesion diagram

Fig. 2. Wood structure Fig. 3. Lignin structure

Fig.5. An adhesive on wood specimens

Soaking for 48 hr. at room temp.

Conditioning at 50% RH at 23 °C, 48 hr.

Sf

1

C2

Fig. 7. Breaking the glued wood specimens and observing the wood surface

• To study lignin depolymerization process

• To study the molecular mechanism and interaction betweenlignin and SP.

• To optimize reaction conditions to achieve higher waterresistance property of lignin-protein based adhesives.

Fig. 9. Thermogravimetric (TG) and derivative thermogravimetric curves of SP/L with different lignin particle size (a), and different SP/L ratios (b)

Fig. 4. Lignin

SP L1 L340

50

60

Degr

ee

Lignin Size

56.11a

43.64c46.73b

12:0 10:2 8:4 6:6

SPI:L3

48.43c

45.88bc

43.64b

54.44a

Fig. 8. Contact angle of SP/L with different lignin particle size (a), and different SP/L ratios (b)

Fig. 10. Wet and dry shear strength of SP/L with different lignin particle size (a), and different SP/L ratios (b)

Fig.11. Stereomicroscope images of cherry wood surface of 12% SP (a), 10% SP blended with 20% lignin (b), and SP:L ratio of 6:6(c)

0 200 400 600

-0.06

-0.04

-0.02

20

40

60

80

100

Temperature (C)

% de

riv. w

t.%

wt.

SPI L1 L3

0 200 400 600

Temperature (C)

12:0 10:2 8:4 6:6

Conclusion• The optimum SP/L ratio of 10:2 (w/w) led to 53.3% increase

in wet strength compared to 10% SP standard

• Lignin improved spreadability, thermoresistance and wet shearstrength of SP

• Lignin showed great potential to improve the water resistanceof soy protein-based adhesives.

a

a ab b

b

c

Source: Wool and Sun 2005

This work was supported by Biomass Research and Development Initiative Program with grant number of 2012-10006-20230 from the U.S. Department of Agriculture National Institute of Food and Agriculture.

Application:

• Packaging and labeling• Wood adhesive

0

2

4

6

8 (A)6.4

(c)4.7

(A)6.3

(b)4.1

(A)6.5

(ab) 3.9

(A)6.4

L3L2

Tens

ile S

tress

(MPa

)

Lignin Size

Wet Dry

SP L1

(a)3.6

12:0 10:2 8:4 6:6

(B)5.0

(a)3.6

(AB) 5.9

(a)3.6

(A)6.4

(b)4.7

(A)6.4

(a)3.6

SPI:L3

Wet Dry

a b