Water absorption by polyamide (PA) 6 studied with two-trace two-dimensional (2T2D) near-infrared (NIR) correlation spectroscopy
Water absorption by polyamide (PA) 6 studied with two-trace two-dimensional (2T2D) near-infrared (NIR) correlation spectroscopy
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DOI：
10.1016/j.molstruc.2020.128389
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发表时间：
2020-10-05
影响因子：
3.8
通讯作者：
Mizukado, Junji
中科院分区：
文献类型：
--
作者：
Shinzawa, Hideyuki;Mizukado, Junji
应用双道二维（2T2D）相关光谱技术研究了PA 6干处理和湿处理后的聚合物体系吸水过程中分子水平的变化。当PA 6经受湿处理时，观察到杨氏模量的显著水平的降低。通过2T2D近红外（NIR）相关光谱检查相应的光谱特征的变化的细节。异步相关谱中观察到的相关模式表明，PA 6吸收的水分子作为增塑剂，通过瓦解PA链之间的氢键桥（尤其是在无定形区域）来增加链的流动性。氢键网络的解体反过来又会使PA 6的弹性性能恶化。另一方面，增加的链移动性也触发PA链的链折叠，最终导致额外的晶体结构的发展。因此，水分子的吸收本质上会引起结晶和非晶结构的种群变化以及非晶链之间氢键的破坏。(c)2020 Elsevier B.V.保留所有权利。
The application of two-trace two-dimensional (2T2D) correlation spectroscopy to dry-treated and wettreated PA 6 is presented to elucidate the molecular-level variation of the polymer system induced by the water absorption. A substantial level of decrease in Young modulus are observed when the PA 6 is subjected to a wet treatment. Fine details of the change in the corresponding spectral feature are examined by 2T2D near-infrared (NIR) correlation spectroscopy. The observed correlation pattern in the asynchronous correlation spectra reveals that the water molecule absorbed by the PA 6 works as a plasticizer to increase the chain mobility by disintegrating the H-bonded bridge between the PA chains especially in the amorphous region. The disintegration of the H-bonding network, in turn, deteriorate the elastic property of the PA 6. On the other hand, the increased chain mobility also triggers chain-folding of the PA chains, eventually leading to the development of additional crystalline structure. Consequently, the absorption of the water molecules essentially induces the populational change in the crystalline and amorphous structures as well as the disruption of the H-bonding between the amorphous chains. (c) 2020 Elsevier B.V. All rights reserved.