Thermal behavior of semicrystalline polymers is notoriously complex due to the metastable nature of polymer crystals. This complexity is evidenced in the multiple melting endotherms frequently observed in the heating traces of various plastics, a phenomenon known as ‘multiple melting behavior’. Extensive research indicates that calorimetric analysis alone may not suffice to fully elucidate the processes occurring during thermal experiments. In this study, we introduce an experimental setup that integrates Fast Scanning Chip Calorimetry, or nanocalorimetry, with real-time polarized optical microscopy. This combination enables in-situ morphological observations during rapid heating/cooling experiments. The setup not only complements thermal analysis but also rivals the capabilities of fast in situ X-ray scattering experiments conducted at synchrotron sources. Our findings show that the obtained data help in identifying melting/recrystallization processes and, therefore, enable the determination of the critical heating rate above which reorganization processes during heating are kinetically bypassed. This ensures that the thermal events detected in calorimetric curves are exclusively due to the initial sample structure, without being influenced by any reorganization that may occur during the heating process. [Display omitted]

中文翻译：

---

检测加热过程中半结晶聚合物的重组：快速扫描芯片量热法与实时光学显微镜相结合的见解

由于聚合物晶体的亚稳态性质，半结晶聚合物的热行为非常复杂。这种复杂性在各种塑料的加热痕迹中经常观察到的多重熔化吸热中得到了证明，这种现象被称为“多重熔化行为”。广泛的研究表明，仅量热分析可能不足以完全阐明热实验期间发生的过程。在这项研究中，我们介绍了一种将快速扫描芯片量热法或纳米量热法与实时偏振光学显微镜相结合的实验装置。这种组合使得能够在快速加热/冷却实验期间进行原位形态观察。该装置不仅补充了热分析，而且还可以与同步加速器源进行的快速原位 X 射线散射实验的能力相媲美。我们的研究结果表明，获得的数据有助于识别熔化/再结晶过程，因此能够确定临界加热速率，高于该速率，加热过程中的重组过程在动力学上被绕过。这确保了量热曲线中检测到的热事件完全归因于初始样品结构，而不受加热过程中可能发生的任何重组的影响。[显示省略]