Sericin as compatibilizer in starch/ polyester blown films

Abstract This study investigated the effects of low concentrations of sericin (≤ 1.5 wt%) in starch- poly(butylene-adipate-co-terephthalate) (PBAT) films. The films were produced by blown extrusion and mechanical, barrier and structural properties were determined. Films containing 1.0 and 1.5 wt% sericin showed higher tensile strength (6.41 and 6.59 MPa) and Young's modulus (90.88 and 132.71 MPa) compared with film without sericin (4.76 MPa and 18.64 MPa). When 0.5 wt% of sericin was used, the elongation was reduced by 62%. The addition of sericin in a concentration of 1.5% (w/w) decreased the water vapor permeability of films from 7.55 to 5.94 g (m s Pa)-1, likely due to the formation of a more homogeneous and compact matrix. Based on these results, a mechanism of action is proposed, whereby sericin acts at the interface of the polymers (starch and PBAT), reducing the interfacial tension and enhancing compatibility.摘要 本研究探究了低浓度丝胶蛋白（sericin，≤1.5 wt%）对淀粉-聚己二酸/对苯二甲酸丁二醇酯（PBAT）复合薄膜的影响。该薄膜通过吹塑挤出法制备，随后对其力学性能、阻隔性能与微观结构进行了测定。与未添加丝胶蛋白的薄膜（拉伸强度4.76 MPa、杨氏模量18.64 MPa）相比，添加1.0 wt%和1.5 wt%丝胶蛋白的复合薄膜拉伸强度分别达6.41 MPa与6.59 MPa，杨氏模量分别达90.88 MPa与132.71 MPa。当添加0.5 wt%丝胶蛋白时，薄膜的断裂伸长率降低了62%。当丝胶蛋白添加浓度为1.5%（w/w）时，薄膜的水蒸气透过率从7.55 g·(m·s·Pa)^-1降至5.94 g·(m·s·Pa)^-1，这一变化或源于复合薄膜形成了更为均匀致密的基体结构。基于上述实验结果，本研究提出了相应的作用机制：丝胶蛋白作用于淀粉与PBAT两种聚合物的界面处，降低界面张力并提升二者的相容性。