Physical properties of two biological cushioning materials from wheat and corn starches
1995
Wang, W. | Flores, R.A. | Huang, C.T.
Physical properties of two biological cushioning materials made from wheat and corn starch extrudates were compared with those of commercial plastic foam cushioning material. Characteristics measured included dimensions, bulk and true densities, and water absorption isotherms at 15, 25, and 40 degrees C. Their properties under simple compression tests and stress relaxation tests were also examined. The C-shaped extrudate from corn starch showed more radial expansion than that of the wheat starch extrudate. But the bulk density and true density of the corn starch extrudates were significantly higher than those of the wheat starch extrudates. Both biological cushioning materials showed similar water absorption isotherms at three temperatures when the equilibrium moisture contents significantly increased as relative humidities increased. The S-shaped plastic foam exhibited lower bulk and true densities. Simple compression tests and stress relaxation tests showed that the biological materials had more unrecoverable plastic deformation than the plastic foams and also indicated a difference between the two extruded cushioning materials.
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