Long Haoyu, Xu Hongsen, Shaoyu Jingwen, Jiang Tianchen, Zhuang Wei, Li Ming, Jin Junyang, Ji Lei, Ying Hanjie, Zhu Chenjie
College of Biotechnique and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China.
National Engineering Technique Research Center for Biotechnique, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, China.
Polymers (Basel). 2023 Feb 10;15(4):895. doi: 10.3390/polym15040895.
The preparation of biodegradable polymer foams with a stable high volume-expansion ratio (VER) is challenging. For example, poly (butylene adipate-co-terephthalate) (PBAT) foams have a low melt strength and high shrinkage. In this study, polylactic acid (PLA), which has a high VER and crystallinity, was added to PBAT to reduce shrinkage during the supercritical molded-bead foaming process. The epoxy chain extender ADR4368 was used both as a chain extender and a compatibilizer to mitigate the linear chain structure and incompatibility and improve the foamability of PBAT. The branched-chain structure increased the energy-storage modulus (G') and complex viscosity (η*), which are the key factors for the growth of cells, by 1-2 orders of magnitude. Subsequently, we innovatively used the CO and N composite gas method. The foam-shrinkage performance was further inhibited; the final foam had a VER of 23.39 and a stable cell was obtained. Finally, after steam forming, the results showed that the mechanical strength of the PBAT/PLA blended composite foam was considerably improved by the addition of PLA. The compressive strength (50%), bending strength, and fracture load by bending reached 270.23 kPa, 0.36 MPa, and 23.32 N, respectively. This study provides a potential strategy for the development of PBAT-based foam packaging materials with stable cell structure, high VER, and excellent mechanical strength.
制备具有稳定高体积膨胀率（VER）的可生物降解聚合物泡沫具有挑战性。例如，聚（己二酸丁二醇酯-对苯二甲酸丁二醇酯）（PBAT）泡沫具有低熔体强度和高收缩率。在本研究中，将具有高VER和结晶度的聚乳酸（PLA）添加到PBAT中，以减少超临界模塑珠发泡过程中的收缩。环氧扩链剂ADR4368既用作扩链剂又用作增容剂，以减轻线性链结构和不相容性，并提高PBAT的发泡性。支链结构使储能模量（G'）和复数粘度（η*）增加了1-2个数量级，而这两个参数是泡孔生长的关键因素。随后，我们创新性地采用了CO和N复合气体法。进一步抑制了泡沫收缩性能；最终泡沫的VER为23.39，并且获得了稳定的泡孔。最后，经过蒸汽成型后，结果表明，添加PLA后，PBAT/PLA共混复合泡沫的机械强度得到了显著提高。压缩强度（50%）、弯曲强度和弯曲断裂载荷分别达到270.23 kPa、0.36 MPa和23.32 N。本研究为开发具有稳定泡孔结构、高VER和优异机械强度的PBAT基泡沫包装材料提供了一种潜在策略。
