纳米二氧化硅/淀粉/聚乳酸三元复合材料力学性能研究

Study on mechanical properties of nano-SiO_2/starch/polylactic acid ternary composites

主要是对淀粉进行增韧改性,研究共混改性后对力学性能的影响。首先是制备不同含量的淀粉/聚乳酸共混材料,通过双螺杆挤出机进行挤出、造粒,在通过注塑机将共混材料注塑成样条,对注塑的样条进行力学性能测试,检测其拉伸强度、断裂伸长率。选出性能做好的一组材料,得到最佳的加工工艺。研究结果表明:在淀粉/聚乳酸共混体系中,随着偶联剂与纳米二氧化硅的增加,共混体系出现了曲线形的变化,随着聚乳酸含量的增加断裂伸长率升高再降低,由此得到了偶联剂、纳米二氧化硅的最佳配比,淀粉与甘油含量的最佳配比。由力学性能得到淀粉材料通过改性后的力学性能优于没有改性前,有明显的断裂伸长率,缓解了全淀粉断裂伸长率低的特点。

In this paper,the toughening modification of starch and the effect of blending modification on mechanical properties were studied.Firstly,starch/polylactic acid blends with different contents were prepared.The blends were extruded and granulated by twin-screw extruder.The blends were injected into splines by injection molding machine.The mechanical properties of the injection molded samples were tested,and the tensile strength and elongation at break were tested.And the best processing technology was received by choosing the materials with the best performance.The results showed that in starch/ polylactic acid blend system,with the increase of coupling agent and nano-silica,the blend system had a curve shape change.With the increase of polylactic acid content,the elongation at break increased and then decreased.Thus,the optimum ratio of coupling agent and nano-silica and the optimum ratio of starch and glycerol content were obtained.The mechanical properties of the modified starch material were better than those of the untreated starch material.It had obvious elongation at break and alleviated the low elongation at break of the whole starch material.