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| Curing and Aging of Adhesives by Low-field Nuclear Magnetic Resonance |
| Received:September 24, 2023 Revised:October 09, 2023 |
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| DOI：10.7643/issn.1672-9242.2023.10.014 |
| KeyWord:low-field nuclear magnetic resonance (LF-NMR) adhesive curing aging cross-linked structure relaxation time curing mechanism |
| Author | Institution |
| ZHAO Min |
Department of Chemical Engineering, Tsinghua University, Beijing , China |
| ZHANG Qian |
Department of Chemical Engineering, Tsinghua University, Beijing , China |
| YANG Rui |
Department of Chemical Engineering, Tsinghua University, Beijing , China |
| LIN Yue-long |
Inner Mongolia Institute of Dynamical Machinery, Hohhot , China |
| BIAN Lei |
Inner Mongolia Institute of Dynamical Machinery, Hohhot , China |
| ZHOU Wen-qing |
Department of Chemical Engineering, Tsinghua University, Beijing , China |
| ZHAO Meng |
Inner Mongolia Institute of Dynamical Machinery, Hohhot , China |
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| Abstract: |
| The work aims to study the curing degree of adhesive and its changes in natural storage and temperature cycle. With the help of the low-field nuclear magnetic resonance (LF-NMR) technology, the change of transverse relaxation time T2 of hydrogen atom in the adhesive during curing and aging was measured to reflect the development of cross-linked structure during curing and the change of the cross-linked structure during 6 months of natural storage and 100 high and low temperature cycles, and clarify the aging mechanism of the adhesive. The results showed that the photo-cross-linking reaction of the light-cured adhesive was completed in 20 min minutes. The thermosetting adhesive reached a high degree of cross-linking after curing at 60 ℃ for 4 h. Curing at 120 ℃ had little effect on the cross-linking degree, but improved the cross-linked structure further. After 100 high and low temperature cycles at ‒45~75 ℃, the cross-linked structure of the adhesive did not change obviously. However, after natural storage for 6 months, the adhesive not only continued to cross-link, but also had a certain relaxation in structure, which would affect its long-term use stability. Low-field nuclear magnetic resonance is sensitive to the mobility of hydrogen atoms, simple in preparation and fast in testing. It is a powerful tool to study the changes of the cross-linked structure, and has important application value in the development of adhesives, the optimization of curing process and the study of curing mechanism. |
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