Chinese Journal of Magnetic Resonance

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Curing Process of Urea-Formaldehyde Resin Studied by Time-Domain Nuclear Magnetic Resonance

SHAO Zhu-wei,ZHANG Ming-hui,LI Xin-yu*   

  1. College of Material Science and Art Design, Inner Mongolia Agricultural University, Huhhot 010018, China
  • Received:2013-10-16 Revised:2014-07-17 Online:2014-09-05 Published:2014-09-05
  • About author:*Corresponding author:ZHANG Ming-hui, Tel: 15849376426,E-mail: zhangmh_email@aliyun.com.
  • Supported by:

    国家自然科学基金资助项目(30800866,31160141).

Abstract:

The curing process urea-formaldehyde resin without the use of hardeners was studied by time-domain nuclear magnetic resonance (TD NMR) at different temperatures. The results showed that urea-formaldehyde resin started curing at about 120 ℃ and ended around 180 ℃. The total peak area for T2 decrease gradually with increasing temperature; and larger changes were observed when the temperature was above 140 ℃. At temperature range between 30 ℃ to 140 ℃, the peak areas decreased gradually and then increased slightly with increasing temperature at T1 (1) = 0.014 ms; the peak areas decreased gradually with increasing temperature at T1 (2) = 327.455 ms. The total peak area for T1 decrease gradually with increasing temperature between 30 ℃ and 180 ℃. The urea-formaldehyde resin system weight decreased gradually with increasing temperature in the solidification process, confirming that cross-linking condensation reaction may occur, giving off formaldehyde and water.

Key words: time-domain nuclear magnetic resonance, solidification, spin-spin relaxation time, spin-lattice relaxation time, urea-formaldehyde resin

CLC Number: