The physical aging behavior of amorphous polylactide constrained against polystyrene in layers of 300 nm, thanks to the layer–multiplying co–extrusion process, was investigated by fast–scanning calorimetry (FSC). By cooling down the sample from the liquid state to the glassy one at very fast scanning rates, it was possible to investigate the structural relaxation of the polymer glass at high temperatures for which the time needed to reach the equilibrium was shortened. Therefore it was possible to perform the study of physical aging in experimental conditions providing an expanded view of the structural relaxation for short aging times. Taking benefit of this property, it was highlighted that the aging kinetics of polylactide occurred significantly slower in the multilayer film, in comparison with a bulk amorphous film. The process of recovery in the multilayer system was found to occur at similar rates, or even slower, than in a three–layer film in which polylactide reached its maximum extent of crystallinity. This was attributed to mobility hindrance that might be inherent to the extrusion conditions or associated with the presence of capped interfaces with polystyrene.

通过快速扫描量热法（FSC）研究了无定形聚丙交酯在多层复合共挤出过程中在300 nm层中对聚苯乙烯的约束，其物理老化行为。通过以非常快的扫描速率将样品从液态冷却到玻璃态，可以研究聚合物玻璃在高温下的结构弛豫，从而缩短了达到平衡所需的时间。因此，有可能在实验条件下进行物理老化的研究，从而为较短的老化时间提供结构弛豫的扩展视图。利用该性质，强调了与大块非晶膜相比，聚丙交酯的老化动力学在多层膜中发生得显着更慢。发现在多层体系中的恢复过程以相似的速率发生，甚至比在其中丙交酯达到最大结晶度的三层薄膜中发生的过程更慢。这归因于流动性障碍，这可能是挤出条件所固有的，或者与聚苯乙烯封端的界面有关。