Work

Quantitative characterization of crystallinity in semi-crystalline fluoropolymer through 19F LF-NMR relaxometry

Year: 2024

Type: article

Abstract: Crystallinity is important to the properties of a semi-crystalline fluoropolymer, such as solubility, mechanical property, bonding strength, etc. This study extended the use of 19F Low-Field Nuclear Magnetic Resonance (19F LF-NMR) to the measurement of crystallinity in the semi-crystalline fluoropolymer F2314, which is the copolymer of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE) with a molar ratio of 1:4 and commonly used as binder in polymer-bonded explosives (PBXs). Based on the difference between spin-spin relaxometry of the 19F in crystalline region and in amorphous region, the crystallinity of F2314 can be qualitatively characterized. The obtained crystallinity exhibited a positive correlation to the time duration of thermal treatment, which is in consistent to the result of Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). Moreover, 19F LF-NMR detected the slight decrease in segmental motion of crystalline region with the increase of crystallinity, and on-line monitored the evolution of segmental motion during heating. This study not only demonstrates the practicality and reliability of 19F LF-NMR in quantification of crystallinity, but also laid the foundation for in-situ characterization of fluoropolymers in PBXs in future work.

Source: Polymer Testing

DOI: 10.1016/j.polymertesting.2024.108654

Authors: Zhangyu Wu, Xianru He, Chunhua Zhu, Huaisong Yong, Xueyan Zhao

Institutions: Southwest Petroleum University, China Academy of Engineering Physics, Leibniz Institute of Polymer Research, University of Twente

Language: English

Topic: NMR spectroscopy and applications

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,580

Funder: National Natural Science Foundation of China