Real-Time Monitoring of Structural Changes in Poly(lactic acid) during Thermal Treatment by High-Speed Terahertz Time-Domain Spectroscopy for Nondestructive Inspection
Real-Time Monitoring of Structural Changes in Poly(lactic acid) during Thermal Treatment by High-Speed Terahertz Time-Domain Spectroscopy for Nondestructive Inspection
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DOI：
10.1021/acsapm.9b00703
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发表时间：
2019-10
影响因子：
5
通讯作者：
Madoka Nakamura;M. Okano;S. Watanabe
中科院分区：
文献类型：
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作者：
Madoka Nakamura;M. Okano;S. Watanabe
聚合物材料中的热致结构变化通常伴随着重要性质的变化，例如机械稳定性。我们展示了一种新兴的技术，用于实时监测聚乳酸（PLA）的热致结构变化。该技术是基于太赫兹时域光谱（THz-TDS），因为在太赫兹频率范围内的PLA的介电函数的光谱反映了宏观分子振动模式，这是密切相关的PLA的形态和结构。通过与传统的X-射线衍射数据的比较，我们确认了聚合物的结构和介电函数的光谱之间的强相关性。我们实现了两个基本的热致结构变化的实时监测：从非晶相到结晶α相的冷结晶过程和玻璃化转变过程。该技术有助于理解聚合物材料的结构变化引起的热处理。
Thermally induced structural changes in polymeric materials are usually accompanied by a change of vital properties such as mechanical stability. We demonstrate an emerging technique for real-time monitoring of thermally induced structural changes of poly(lactic acid) (PLA). The technique is based on terahertz time-domain spectroscopy (THz-TDS) because spectra of the dielectric function of PLA in the terahertz frequency range reflect macroscopic molecular vibration modes which are strongly linked to the PLA morphology and structure. By comparison with conventional X-ray diffraction data, we confirm a strong correlation between the polymer structure and the spectra of the dielectric function. We achieve real-time monitoring of two essential thermally induced structural changes: the cold crystallization process from amorphous phase to the crystalline α-phase and the glass transition process. The proposed technique is useful for understanding the structural changes in polymeric materials induced by thermal t...