With increasing concerns about environmental protection and garbage handling, natural renewable materials such as starch,
cellulose and other natural fibers become more and more popular in packaging materials manufacturing. In this study, physical
and mechanical properties of extruded foam composites, prepared from starch acetate and cellulose/corn cob, were evaluated. A
split-plot experimental design was used to compare selected functional properties of foams produced from starch acetate blended
with ground corncobs, compared to blending with cellulose, and with different ethanol contents. Extrusions were conducted in a
twin-screw extruder with 160 ◦C barrel temperature and 225 rpm screw speed. Physical properties of extrudates were measured
including radial expansion ratio, unit density, bulk density, and water absorption index. Mechanical properties including unit
spring index, bulk spring index, and compression strength were measured. Scanning electron microscopy was used to compare
the macromolecular structures of the two types of starch acetate blends. Blending with corncobs significantly hindered radial
expansion of starch acetate foams, whereas cellulose did not affect expansion significantly. Higher compression strength was
obtained with higher corncob content. Although ethanol penetration assisted in the formation of a starch acetate–fiber matrix,
corncob blends produced inferior linkages and cell development in the foams than foams produced with cellulose blends.
© 2003 Published by Elsevier B.V.
With increasing concerns about environmental protection and garbage handling, natural renewable materials such as starch,cellulose and other natural fibers become more and more popular in packaging materials manufacturing. In this study, physicaland mechanical properties of extruded foam composites, prepared from starch acetate and cellulose/corn cob, were evaluated. Asplit-plot experimental design was used to compare selected functional properties of foams produced from starch acetate blendedwith ground corncobs, compared to blending with cellulose, and with different ethanol contents. Extrusions were conducted in atwin-screw extruder with 160 ◦C barrel temperature and 225 rpm screw speed. Physical properties of extrudates were measuredincluding radial expansion ratio, unit density, bulk density, and water absorption index. Mechanical properties including unitspring index, bulk spring index, and compression strength were measured. Scanning electron microscopy was used to comparethe macromolecular structures of the two types of starch acetate blends. Blending with corncobs significantly hindered radialexpansion of starch acetate foams, whereas cellulose did not affect expansion significantly. Higher compression strength wasobtained with higher corncob content. Although ethanol penetration assisted in the formation of a starch acetate–fiber matrix,corncob blends produced inferior linkages and cell development in the foams than foams produced with cellulose blends.© 2003 Published by Elsevier B.V.
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