Green and renewable foaming poly(lactic acid) (PLA) represents one of the promising developments in PLA materials. This study is the first to use the lignin graft PLA copolymer (LG‐g‐PLA) to improve the foamability of PLA as a biobased nucleating agent. This agent was synthesized via ring‐opening polymerization of lignin and lactide. The effects of LG‐g‐PLA on cell nucleation induced by the crystallization, rheological behavior, and foamability of PLA were evaluated. Results indicated that LG‐g‐PLA can improve the crystallization rate and crystallinity of PLA, and play a significant nucleation role in the microcellular foam processing of PLA. LG‐g‐PLA improved the foam morphology of PLA, obtaining a reduced and uniform cell size as well as increased expansion ratio and cell density. With the addition of 3 wt% LG‐g‐PLA content, the PLA/LG‐g‐PLA foams increased the compressive strength 1.6 times than that of neat PLA foams. The improved foaming properties of PLA via a biobased nucleating agent show potential for the production and application of green biodegradable foams.

中文翻译：

---

通过木质素接枝聚乳酸作为生物基成核剂提高微孔聚乳酸泡沫的膨胀率，孔密度和抗压强度

绿色和可再生的发泡聚乳酸（PLA）代表了PLA材料的发展前景之一。这项研究是首次使用木质素接枝PLA共聚物（LG-g-PLA）来提高PLA作为生物基成核剂的发泡性。该试剂是通过木质素和丙交酯的开环聚合反应合成的。评估了LG-g-PLA对PLA结晶，流变行为和可发泡性诱导的细胞成核的影响。结果表明，LG-g-PLA可以提高PLA的结晶速率和结晶度，并在PLA的微孔泡沫加工中发挥重要的成核作用。LG‐g‐PLA改善了PLA的泡沫形态，减小了孔的大小并使之均匀，并提高了膨胀率和孔的密度。通过添加3 wt％的LG‐g‐PLA含量，PLA / LG-g-PLA泡沫的压缩强度是纯PLA泡沫的1.6倍。通过生物基成核剂改善的PLA发泡性能显示了绿色可生物降解泡沫的生产和应用潜力。