Study of biodegradable polyactide/poly(butylene adipate-co-terephthalate) blends
Study of biodegradable polyactide/poly(butylene adipate-co-terephthalate) blends
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DOI：
10.1021/bm050581q
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发表时间：
2006-01-01
影响因子：
6.2
通讯作者：
Zhang, JW
中科院分区：
文献类型：
--
作者：
Jiang, L;Wolcott, MP;Zhang, JW
聚乳酸（PLA）和聚（己二酸丁二醇酯-对苯二甲酸丁二醇酯）（PBAT）都是可生物降解的聚合物。它们是热塑性塑料，可以使用大多数传统的聚合物加工方法进行加工。PLA的强度和模量高（分别为63 MPa和3.4 GPa）但易碎（断裂应变为3.8%），而PBAT是柔性和坚韧的（断裂应变类似于710%）。鉴于它们的互补性质，将PLA与PBAT共混成为改善PLA性能而不损害其生物降解性的自然选择。在这项研究中，PLA和PBAT熔融共混使用双螺杆挤出机。共混物的熔体弹性和粘度随PBAT的浓度增加而增加。研究了PLA组分的结晶、共混物的相形态、力学性能和增韧机理。该共混物包含不混溶的两相系统，其中PBAT以类似于300 nm域的形式均匀分散在PLA基质内。PBAT组分的加入加快了PLA的结晶速率，但对其最终结晶度影响不大。随着PBAT含量的增加（5- 20wt%），共混物的拉伸强度和模量降低，而伸长率和韧性显著增加。通过拉伸试验和扫描电子显微镜（SEM）观察，PBAT的加入使PLA的断裂模式由纯PLA的脆性断裂转变为共混物的韧性断裂。PLA和PBAT域之间的脱粘引起PLA基质韧带的大的塑性变形。
Both polylactide (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are biodegradable polymers. They are thermoplastics which can be processed using most conventional polymer processing methods. PLA is high in strength and modulus (63 MPa and 3.4 GPa, respectively) but brittle (strain at break 3.8%) while PBAT is flexible and tough (strain at break similar to 710%). In view of their complementary properties, blending PLA with PBAT becomes a natural choice to improve PLA properties without compromising its biodegradability. In this study, PLA and PBAT were melt blended using a twin screw extruder. Melt elasticity and viscosity of the blends increased with the concentration of PBAT. Crystallization of the PLA component, phase morphology of the blend, mechanical properties, and toughening mechanism were investigated. The blend comprised an immiscible, two-phase system with the PBAT evenly dispersed in the form of similar to 300 nm domains within the PLA matrix. The PBAT component accelerated the crystallization rate of PLA but had little effect on its final degree of crystallinity. With the increase in PBAT content (5-20 wt %), the blend showed decreased tensile strength and modulus; however, elongation and toughness were dramatically increased. With the addition of PBAT, the failure mode changed from brittle fracture of the neat PLA to ductile fracture of the blend as demonstrated by tensile test and scanning electron microcopy (SEM) micrographs. Debonding between the PLA and PBAT domains induced large plastic deformation in PLA matrix ligaments.