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Mechanical properties of biodegradable soy-protein plastics

Published online by Cambridge University Press:  03 March 2011

C.H. Schilling ,
T. Babcock ,
S. Wang  and
J. Jane
C.H. Schilling
Affiliation:
Ames Laboratory and Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011-3110
T. Babcock
Affiliation:
Department of Food Science and Human Nutrition, Center for Crops Utilization Research, Iowa State University, Ames, Iowa 50011-3110
S. Wang
Affiliation:
Department of Food Science and Human Nutrition, Center for Crops Utilization Research, Iowa State University, Ames, Iowa 50011-3110
J. Jane
Affiliation:
Department of Food Science and Human Nutrition, Center for Crops Utilization Research, Iowa State University, Ames, Iowa 50011-3110
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Abstract

Experiments were performed to evaluate the room-temperature mechanical properties of soy-protein that were compression-molded with varying concentrations of glycerin plasticizer. Specimens exhibited stiff and brittle behavior with good tensile strength reliability based on Weibull statistics analysis. Raising the glycerin concentration from 0 to 20% progressively increased the tensile strain-to-failure from 1.1 to 1.8% and reduced the tensile strength from 42.1 to 23.6 MPa. the tangent modulus from 4.56 to 1.79 GPa, and the Rockwell hardness from R118.4 to R75.7. Ultrasonic measurements indicated that raising the glycerin concentration from 0 to 20% increased Poisson's ratio from 0.348 to 0.409 and reduced Young's modulus from 7.01 to 5.4 GPa and the shear modulus from 2.5 to 1.8 GPa. Significant increases in the tensile strength and the strength reliability resulted from eliminating Griffith's flaws by sieving the press powder before compression molding. Rockwell hardness rapidly decreased upon immersing these plastics in water at 25 °C, an effect which was pronounced for the glycerin-containing specimens.

Type
Articles
Information
Journal of Materials Research , Volume 10 , Issue 9 , September 1995 , pp. 2197 - 2202
Copyright
Copyright © Materials Research Society 1995

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References

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