PCL/PLLA共混体系的微相分离结构调控及力学性能和气体水蒸气阻隔性能

Microphase Separation Structure Regulation of Poly(ε-caprolactone)/Poly(L-lactide)Blends and Its Mechanical,Gas and Water Vapor Barrier Properties

采用熔融共混法制备了不同聚乳酸(PLLA)组分的聚己内酯/聚乳酸(PCL/PLLA)非均相共混薄膜,研究了其力学性能、气体和水蒸气阻隔性能,并探讨了共混物相结构与各阻隔性能之间的关系。结果表明,不同PLLA共混比例的PCL/PLLA共混膜形成了具有不同相分离结构的非均相体系。当PLLA共混比例高于50%时,共混薄膜体系的相分离结构和相容性得到改善,共混膜的拉伸强度和弹性模量大幅度增加,同时保持了较高的断裂伸长率,而气体和水蒸气透过性却明显降低。相比于纯PCL,PCL/PLLA(75)共混膜的拉伸强度和弹性模量分别达到68.1 MPa和1136.4 MPa,较PCL分别增加了166%和289%;5℃时,PCL/PLLA(75)共混膜的O2和CO2透过系数分别降低了70%和87%;此外,在室温条件下,PCL/PLLA(75)共混膜的水蒸气透过系数降低了31%。

Poly(ε-caprolactone)/poly(L-lactide)(PCL/PLLA)heterogeneous blend films with different PLLA blend composition ratios were prepared by melt blending.Based on the compatibility and phase structure of the blends,the mechanical properties,gas and water vapor barrier properties of the blends were studied,meanwhile,the relationship between the microphase separation structure and packaging properties of the blends was discussed.The results show that PCL/PLLA blend membranes with different PLLA blending ratios formed heterogeneous systems with different phase separation structures.When the PLLA blending ratio is higher than 50%,the phase separation structure and compatibility of the blend film system are improved,the tensile strength and elastic modulus of the blend film increase greatly accordingly,while maintaining a high elongation at break,nevertheless gas and water vapor permeability decrease significantly.Compared with the pure PCL,the tensile strength and elastic modulus of PCL/PLLA(75)blend films is 68.1 MPa and 1136.4 MPa,which are increased by 166%and 289%respectively;the CO2 permeability and O2 permeability of PCL/PLLA(75)blend films are decreased by 70%and 87%respectively at 5℃;and the water vapor permeability of it is decreased by 31%at room temperature.