水发泡淀粉挤出泡沫的结构与性能

以水为发泡剂，普通玉米淀粉为原料，采用双螺杆挤出机制备淀粉泡沫材料，研究了发泡剂用量及聚乙烯醇的加入量对泡沫材料结构与性能的影响。 用扫描电子显微镜观察了泡沫材料截面的形态，用万能材料试验机测试了泡沫材料的力学性能。 结果表明，水的质量分数为8%时淀粉泡沫径向膨胀率和发泡倍率最高，分别为22倍和17.6倍，压缩模量最高（4.07 MPa）。 加入质量分数10%的聚乙烯醇(PVA)使淀粉泡沫的孔径变大至1.29 mm，壁厚增加至82.43 μm，同时压缩模量增加至9.70 MPa。

Structure and Properties of Starch Extruded Foams with Water as Blowing Agent

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).