Wu Minghui, Ren Qian, Zhu Xiuyu, Li Wanwan, Luo Haibin, Wu Fei, Wang Long, Zheng Wenge, Cui Ping, Yi Xiaosu
Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang Province 315201, PR China; Faculty of Science and Engineering, University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo 315000, PR China.
Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang Province 315201, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
Int J Biol Macromol. 2023 Aug 1;245:125490. doi: 10.1016/j.ijbiomac.2023.125490. Epub 2023 Jun 20.
Biodegradable poly(lactic acid) (PLA) foams have drawn increasing attention due to environmental challenges and petroleum crisis. However, it still remains a challenge to prepare PLA foams with fine cellular structures and high impact property, which significantly hinders its widespread application. Herein, phase interface-enhanced PLA/ poly(butylene adipate-co-terephthalate) (PBAT) blend foam, modified by a reactive compatibilizer through a simple reactive extrusion, was produced via a core-back foam injection molding technique. The obtained PLA blend foams displayed an impact strength as high as 49.1 kJ/m, which was 9.3 and 6.4 times that of the unmodified PLA/PBAT blend and its corresponding foam, respectively. It proved that the interfacial adhesion and cell size both strongly affected the impact strength of injection-molded PLA/PBAT foams, and two major conclusions were proposed. First, enhancing interfacial adhesion could cause a brittle-tough transition of PLA/PBAT foams. Additionally, for foams with high interfacial adhesion, small cell size (<12 μm) was more favorable for the stretching of cells and extension of the whitened region in comparison with big cell size (cell size >60 μm), leading to the drastic toughening of PLA blends. This study provides a feasible, industrially scalable and practical strategy to prepare super toughened and fully biodegradable PLA materials.
由于环境挑战和石油危机，可生物降解的聚乳酸（PLA）泡沫材料受到了越来越多的关注。然而，制备具有精细泡孔结构和高冲击性能的PLA泡沫材料仍然是一个挑战，这严重阻碍了其广泛应用。在此，通过一种简单的反应挤出工艺，采用反应性增容剂对相界面增强的聚乳酸/聚（己二酸丁二醇酯-co-对苯二甲酸丁二醇酯）（PBAT）共混泡沫进行改性，通过芯层-背层泡沫注射成型技术制备而成。所获得的PLA共混泡沫材料的冲击强度高达49.1kJ/m，分别是未改性的PLA/PBAT共混物及其相应泡沫的9.3倍和6.4倍。结果表明，界面粘结力和泡孔尺寸均对注塑PLA/PBAT泡沫的冲击强度有显著影响，并提出了两个主要结论。首先，增强界面粘结力可使PLA/PBAT泡沫发生脆韧转变。此外，对于具有高界面粘结力的泡沫，与大泡孔尺寸（泡孔尺寸>60μm）相比，小泡孔尺寸（<12μm）更有利于泡孔的拉伸和发白区域的扩展，从而导致PLA共混物的显著增韧。本研究为制备超韧且完全可生物降解的PLA材料提供了一种可行、可工业规模化且实用的策略。
