Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
Int J Biol Macromol. 2024 Oct;278(Pt 4):135053. doi: 10.1016/j.ijbiomac.2024.135053. Epub 2024 Aug 24.
A continuing challenge in the most common biodegradable polyester of poly(l-lactide) (PLLA) is to improve the degradation rate in the environment, though it has been widely used in packaging and medical applications. In this study, PLLA/poly(ether-block-amide) (PEBA) blends are prepared by melt blending to investigate the effect of PEBA component on the phase morphology, thermal behavior, mechanical properties, and hydrolytic degradation of the blends. The incorporation of PEBA component is beneficial to the improved toughness and increased water absorption of the blends, and accelerated hydrolytic degradation of PLLA. The blend exhibits the optimal mechanical and hydrolytic degradation properties when the blend mass ratio of PLLA/PEBA is 80/20. The toughness of the blend is increased by 390 % compared to that of pure PLLA. After being hydrolyzed at 58 °C for 240 h, the water absorption, the mass loss and the decrease of molecular weight of the blend is increased by 138 %, 160 % and 40 %, respectively, indicating faster hydrolytic degradation rate of the blend than that of pure PLLA. Furthermore, the accelerated hydrolytic degradation mechanism of PLLA in the blend is revealed. The amorphous region of PLLA is hydrolyzed initially at the phase interface of the blend, and subsequently the crystalline structure of PLLA is degraded. The hydrolysis process causes a change in the relative content of crystalline regions in the system, resulting in an increase in crystallinity of PLLA first and then decrease. These findings provide a new strategy for the design of novel degradable PLLA materials for practical applications.
聚 L-乳酸（PLLA）是最常见的可生物降解聚酯之一，目前面临的一个持续挑战是提高其在环境中的降解速率，尽管它已广泛应用于包装和医疗领域。在这项研究中，通过熔融共混制备了 PLLA/聚醚嵌段酰胺（PEBA）共混物，以研究 PEBA 组分对共混物的相形态、热行为、力学性能和水解降解的影响。PEBA 组分的加入有利于提高共混物的韧性和吸水性，并加速 PLLA 的水解降解。当 PLLA/PEBA 的共混质量比为 80/20 时，共混物表现出最佳的力学性能和水解降解性能。与纯 PLLA 相比，共混物的韧性提高了 390%。在 58°C 下水解 240 h 后，共混物的吸水率、质量损失和分子量降低分别增加了 138%、160%和 40%，表明共混物的水解降解速率比纯 PLLA 更快。此外，揭示了共混物中 PLLA 的加速水解降解机制。共混物的相界面处首先水解 PLLA 的无定形区域，随后降解 PLLA 的结晶结构。水解过程导致体系中结晶区域的相对含量发生变化，导致 PLLA 的结晶度先增加后降低。这些发现为设计用于实际应用的新型可降解 PLLA 材料提供了新策略。
