转化(遗传学)
材料科学
相(物质)
单体
尼龙6
高分子科学
结晶学
Crystal(编程语言)
化学工程
聚合物
高分子化学
复合材料
化学
有机化学
计算机科学
工程类
生物化学
基因
程序设计语言
作者
Zihan Li,Pengpeng Yang,Haodong Liu,Jun Liu,Sha Zhu,Xiaojie Li,Wei Zhuang,Jinglan Wu,Hanjie Ying
出处
期刊:Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
[Wiley]
日期:2020-07-01
卷期号:76 (4): 524-533
被引量:12
标识
DOI:10.1107/s2052520620006265
摘要
Nylon 5T is one of the bio-based nylons, its raw material 1,5-pentanediamine is derived from biomass resources and produced by biological methods. 1,5-pentanediamine-terephthalate (PDA-TPA) is the monomeric salt for nylon 5T polymerization, and its own product quality has a significant impact on the performance of nylon 5T. PDA-TPA was prepared by anti-solvent crystallization in this study. It exists in two solid forms, a monohydrate [form (I)] and an anhydrous phase [form (II)]. The transition temperature of the two phases was around 65°C in the given ethanol–water binary (7:1) mixture. The characterization of monohydrate and anhydrate phases regarding structures and stabilities was carefully carried out using powder X-ray diffraction, single crystal X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, hot-stage microscopy and Fourier transform infrared spectroscopy. The relationship between the molecular interactions of monohydrate and anhydrate phases under different packing architectures and their thermal behaviours was analysed and established. In addition, the relationships between the structures and thermal behaviours for the two solid forms were analysed and established. In addition, the effect of solvent on phase conversion, the relationships between the temperature and water activity, as well as the relative stability of monohydrate and anhydrate phases under different thermodynamic conditions, were investigated by solid–solid transformation and solvent-mediated transformation experiments. It was obvious that the transition temperature of monohydrate and anhydrate phases of PDA-TPA was significantly influenced by water activity, and the larger the value of water activity is, the higher is the transition temperature. These studies give insight into the transformation of nylon 5T monomer salt and contribute to the control of target crystal preparation.
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