摘要
利用时域核磁共振（TD NMR）技术对无固化剂的脲醛树脂在不同温度下固化过程进行了研究,实验结果表明：脲醛树脂在120℃左右时开始固化,在180℃左右时固化反应基本结束.随着温度的升高,自旋-自旋弛豫时间（T2）的总峰面积逐渐减少,当温度高于140℃时,总峰面积减少的程度较大.在30℃~140℃温度范围内,自旋-晶格弛豫时间T1（1）=0.014ms时,随着温度的升高,峰面积先逐渐减少而后略微增加;T1（2）=327.455 ms时,随着温度的升高,峰面积逐渐减少.在30℃~180℃温度范围内,自旋-晶格弛豫时间（T1）分布的总峰面积随着温度的升高而逐渐减少.在固化过程中,随着温度的升高,脲醛树脂体系的质量逐渐减少,说明脲醛树脂胶黏剂体系发生了缩聚交联反应,同时生成了甲醛和水.
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.
出处
《波谱学杂志》
CAS
CSCD
北大核心
2014年第3期372-380,共9页
Chinese Journal of Magnetic Resonance
基金
国家自然科学基金资助项目(30800866
31160141)
