醋酸淀粉/聚乳酸的制备及性能的影响研究

采用自设计的双螺杆结构挤出制备聚乳酸(PLA)/醋酸淀粉(AS)的全生物降解材料,考察材料的AS的含量和取代度对复合材料动态流变性能、机械性能的影响。研究结果表明,AS含量明显影响复合材料的力学性能、复合黏度和储能模量:当AS含量从45%增加到70%,材料的拉伸强度下降,复数黏度和储能模量则提高。随着AS取代度由1.0上升为3.0,复合材料的复数黏度和储能模量下降,拉伸强度由12.0MPa上升为15.5MPa。对复合材料进行电镜扫描分析发现,AS以海岛结构形式分散在PLA的连续相中,取代度2.0的AS与PLA相容性最好,当其质量含量达到70%,材料的拉伸强度仍然不低于10.0MPa,具有较好的机械强度。

Preparation and characterization of acetylated starch/poly (lactic-acid) blends

The blend of poly(lactic-acid)(PLA) and acetylated starch (AS) with different substitute degree (DS) were prepared by a co-rotating twin-screw extruder. The effect of content and DS value of AS on the properties of the blends, including dynamical rheological properties, mechanical properties and morphology were investigated. The results show content AS affected the tensile strength, complex viscosity and the storage modulus of the blend significantly, when the AS content increase from 45% to 70%, the tensile strength of blend decreased while both complex viscosity and the storage modulus increased. The complex viscosity and the storage modulus of blend decreased while the tensile strength increased to 15.5MPa when the DS of AS ranged from 1.0 to 3. 0, The morphology of PLA/AS show sea-island structure and AS particles dispersed in the PLA phase. AS which DS was 2. 0 had best interfacial compatibility of PLA ,when its content was 70% ,the tensile strength of blend was higher than 10.0MPa.