Abstract:

Starch foams were prepared with a twin-screw extruder from normal corn starch as raw material and water as blowing agent. The effects of blowing agent content and blend of poly(vinyl ethanol) on the structure and properties of the extruded foams were studied. The structure and mechanical properties of starch foams were characterized by means of a scanning electron microscope and a universal material testing machine respectively. The results indicate that the starch foams extruded with 8%(mass fraction) water reached the greatest radial expansion ratio and volume expansion ratio, which were 22 and 17.6 respectively, and the greatest compressive modulus(4.07 MPa).The extruded starch foams blended with 10%(mass fraction) PVA reached greater cell size(1.29 mm), cell thickness(82.43 μm), and compressive modulus(9.70 MPa).

Key words: starch, extruded foam, structure, property