This paper investigated the condensed state structure evolution of pre-crystallized polylactide (PLA) under supercritical CO₂ (scCO₂) and its influence on the foaming behavior of PLA. An interesting phenomenon was found, in which the pre-crystallized PLA can form a layered condensed state structure with a molten skin layer and a crystalline core at low temperatures under scCO₂, and as the temperature increases, the width of the molten skin layer and the melting degree of the core gradually increases until a uniform non-layered molten state structure is formed. On this basis, layered and non-layered PLA foams were prepared at low and high temperatures, respectively. For the non-layered PLA foam, the skin layer and the core show similar closed or opened cell structure, where the open-cell PLA foams exhibit excellent oil-sorption properties. This paper provides a solvent-free idea for the green fabrication of bio-based and biodegradable oil-sorption foam.

研究了超临界CO ₂（scCO ₂）下预结晶聚丙交酯（PLA）的凝聚态结构演变及其对PLA发泡行为的影响。发现了一个有趣的现象，其中预结晶的PLA可以在低温下在scCO ₂下形成具有熔融皮层和结晶核的层状凝聚态结构。并且，随着温度的升高，熔融皮层的宽度和芯的熔融度逐渐增加，直到形成均匀的非层状熔融态结构。在此基础上，分别在低温和​​高温下制备层状和非层状PLA泡沫。对于非层状的PLA泡沫，表层和芯层显示出类似的闭孔或开孔结构，其中开孔的PLA泡沫表现出优异的吸油性能。本文为绿色制造生物基可生物降解吸油泡沫提供了一种无溶剂的想法。