Curing mechanism of resole phenolic resin based on variable temperature FTIR spectra and thermogravimetry-mass spectrometry
Curing mechanism of resole phenolic resin based on variable temperature FTIR spectra and thermogravimetry-mass spectrometry
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DOI：
10.1177/09673911221102114
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发表时间：
2022-05-01
影响因子：
2.1
通讯作者：
Wang, Jinming
中科院分区：
文献类型：
--
作者：
Hu, Honglin;Wang, Wei;Wang, Jinming
针对Ba（OH）（2）催化酚醛树脂固化反应机理尚不清楚的问题，引入对-对亚甲基指数、邻-对亚甲基指数、邻-邻亚甲基指数、羟甲基指数和醚化指数，定量研究了树脂在90-230 ℃固化温度范围内的化学结构.采用变温红外光谱（FT-IR）分析了固化产物的化学结构，采用热重-质谱（TGA-MS）分析了固化温度对固化产物的影响。最后总结了90 ~ 230 ℃的固化机理。结果表明，在90-120 ℃范围内，主要反应是生成对-对亚甲基。现阶段很难形成邻位亚甲基桥。在120-160 ℃的范围内，主要反应是形成对-对亚甲基。从160 ℃到190 ℃，主要反应是醚键的断裂，羰基和丙基桥的形成。在190 ℃以上，主要反应为酚羟基之间的缩聚反应和羰基的生成反应。醚键在230摄氏度以上完全断裂。本工作为研究其固化机理提供了一种新的方法。这对合理设计酚醛树脂基复合材料的固化工艺具有一定的指导意义。
To solve the problem that the curing mechanism evolution of phenolic resin catalyzed by Ba(OH)(2) remained unclear, the p-p methylene index, o-p methylene index, o-o methylene index, hydroxymethyl index, and ether index were introduced to quantitatively investigate the chemical structure of resin in the curing temperature range of 90-230 degrees C. The chemical structures were investigated by variable temperature FT-IR. The gas products released with the increase of curing temperature were characterized by Thermogravimetry-Mass Spectrometry. The curing mechanism from 90 degrees C to 230 degrees C was concluded finally. The results show that the main reaction is the formation of the p-p methylene group in the range of 90-120 degrees C. It is difficult to form the o-p methylene bridge at this stage. In the range of 120-160 degrees C, the main reaction is the formation of the p-p methylene group. From 160 degrees C to 190 degrees C, the main reactions are the breaking of the ether bond, the formation of the carbonyl group and the propyl bridge. Above 190 degrees C, the main reactions are polycondensation reaction among phenolic hydroxyl groups, and the formation reaction of carbonyl groups. The ether bond breaks completely above 230 degrees C. This work provides a new method to investigate the curing mechanism. It is a benefit for the rational design of the curing process of phenolic resin-based composites.