Abstract
Soybean protein is a potential material for manufacturing of biodegradable plastics. The objective of this investigation was to characterize the thermal and mechanical properties of plastics made from sodium dodecyl sulfate (SDS)-modified soy proteins. Soy protein isolate (SPI) was prepared from defatted soy flour, modified with various concentrations of SDS, and then molded into plastics. The temperatures of denaturation of the modified soy protein increased at low SDS concentration and then decreased at high SDS concentration. At the same SDS concentration, the plastics molded from the modified soy proteins showed a similar temperature of denaturation, but a lower enthalpy of denaturation compared to the modified soy protein. Young's modulus of the plastics decreased as SDS concentration increased, and the tensile strength and strain at break of the plastics reached a maximum value at 1% SDS modification. Two glass transition temperatures were identified corresponding to the 7S and 11S globulins in SPI by dynamic mechanical analysis, and they decreased as SDS concentration increased. The SDS modification increased the water absorption of the plastics.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
U. S. Environmental Protection Agency (1999) Characterization of Municipal SolidWaste in the United States: 1998 Update, Washington, DC, pp. 40–44.
ASTM Handbook (1992) Standard Terminology Relating to Plastics, D883-92, American Society for Testing and Materials, Philadelphia, PA, pp. 325–334.
L. McCarthy-Bates (1993) Plast. World. 51, 22–27. SDS
S. Wang, H. J. Sue, and J. L. Jane (1996) Pure Appl. Chem. A33, 557–569.
I. Paetau, C. Z. Chen, and J. L. Jane (1994) Ind. Eng. Chem. Res. 33, 1821–1827.
X. Q. Mo, X. Z. Sun, and Y. Q. Wang (1999) J. Appl. Polym. Sci. 73, 2595–2602.
J. Jane and S. Wang (1996) US Patent 5,523,293.
J. U. Otaigbe, H. Goel, and T. Babcock (1999) J. Elastomers Plastics 31, 56–71.
H. V. Pol and A. A. Ogale (2000) ANTEC 46, 1751–1755.
J. U. Otaigbe and D. O. Adams (1997) J. Environ. Polym. Degrad. 5, 199–208.
J. John and M. Bhattacharya (1999) Polym. Int. 48, 1165–1172.
S. Zhang, P. Mungara, and J. Jane (1998) Polym. Prepr. 39, 162–164.
I. Paetau, C. Z. Chen, and J. L. Jane (1994) J. Environ. Polym. Degrad. 2, 211–217.
C. H. Schilling, T. Babcock, S. Wang, and J. Jane (1995) J. Mater. Res. 10, 2197–2202.
Y. T.-P. Ly, L. A. Johnson, and J. Jane (1998) in D. L. Kaplan (Ed.), Biopolymers from Renewable Resources, Springer, New York, pp. 144–176.
W. J. Wolf (1970) J. Agr. Food Chem. 18, 969–976.
Y. V. Wu and G. E. Inglett (1974) J. Food Sci. 39, 218–225.
I. Nir, Y. Fekdman, A. Aserin, and N. Garti (1994) J. Food Sci. 59, 606–610.
N. S. Hettiarachchy, U. Kalapathy, and D. J. Myers (1995) J. Am. Oil Chem. Soc. 72, 1461–1464.
X. Z. Sun and K. Bian (1999) J. Am. Oil Chem. Soc. 76, 977–980. SDS.
W. N. Huang and X. Z. Sun (2000) J. Am. Oil Chem. Soc. 77, 101–104.
C. Tanford (1968) in C. B. Anfinsen, M. L. Anson, J. T. Edsall, and F. M. Richard (Eds.), Advances in Protein Chemistry, Academic Press, New York, pp. 121–281.
X. Q. Mo and X. Z. Sun (2000) J. Am. Oil Chem. Soc. 78, 867–872.
ASTM Standards D638-91 (1993) Standard Test Methods for Tensile Properties of Plastics, American Society for Testing and Materials, Philadelphia, pp. 161–173.
ASTM Standards D570-81 (Reapproved 1988) (1993) Standard Test Methods for Water Absorption of Plastics, American Society for Testing and Materials, Philadelphia, pp. 143–145.
N. K. D. Kella and M. S. N. Rao (1985) Int. J. Peptide Res. 25, 308–315.
B. R. Sureshchandra, A. G. Appu Rao, and M. S. Narasinga Rao (1987) J. Agric. Food Chem. 35, 244–247.
A. M. Hermansson (1978) J. Text. Stud. 9, 33–58.
Z. K. Zhong and X. S. Sun (2000) J. Appl. Polym. Sci. 81, 166–175.
A. Morales and J. L. Kokini (1997) Biotechnol. Prog. 13, 624–629. 1. U. S. Environmental Protection Agency (1999) Characterization
L. H. Sperling (1992) Introduction to Polymer Science, John Wiley & Sons, New York. pp. 303–381.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mo, X., Sun, X. Thermal and Mechanical Properties of Plastics Molded from Sodium Dodecyl Sulfate-Modified Soy Protein Isolates. Journal of Polymers and the Environment 8, 161–166 (2000). https://doi.org/10.1023/A:1015241609497
Issue Date:
DOI: https://doi.org/10.1023/A:1015241609497