Kinetics of early stages of resorcinol-formaldehyde polymerization investigated by solution-phase nuclear magnetic resonance spectroscopy
Kinetics of early stages of resorcinol-formaldehyde polymerization investigated by solution-phase nuclear magnetic resonance spectroscopy
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DOI：
10.1016/j.polymer.2016.12.069
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发表时间：
2017-02-10
期刊：
影响因子：
4.6
通讯作者：
Sefcik, Jan
中科院分区：
文献类型：
--
作者：
Gaca, Katarzyna Z.;Parkinson, John A.;Sefcik, Jan
间苯二酚和甲醛的反应进行了定量监测，通过H-1和C-13 NMR光谱在室温下（293 K）热处理前，导致形成的有机凝胶。我们发现，用甲醛取代间苯二酚开始于一个令人惊讶的快速步骤，然后是一个更渐进的耗尽反应物。在混合试剂后立即观察到具有单体和二聚体羟甲基的取代物质，其中基于甲酰胺的溶液物质的消耗比例在30%和50%之间。取代的间苯二酚物质可以全部通过溶液相NMR在环境条件下在它们在加热时形成纳米尺度簇之前进行解释。因此可以预期，间苯二酚甲醛凝胶的最终性质不仅取决于反应混合物的组成和高温处理的持续时间，而且还取决于试剂混合的方式和时间（迄今为止被忽视的合成步骤），因为在热处理开始之前可以产生不同量的替代取代的间苯二酚。(C)2017爱思唯尔有限公司版权所有
Resorcinol and formaldehyde reactions were quantitatively monitored by means of H-1 and C-13 NMR spectroscopy at room temperature (293 K) before heat treatment leading to formation of organic gels. We found that resorcinol substitution with formaldehyde starts with an initial surprisingly rapid step followed by a more gradual depletion of the reactants. Substituted species with both monomeric and dimeric hydroxymethyl groups were observed immediately after mixing of the reagents with the proportion of formaldehyde-based solution species consumed between 30 and 50%. Substituted resorcinol species can be all accounted for by solution-phase NMR at ambient conditions before they form nano scale clusters upon heating. It can therefore be expected that the final properties of resorcinol formaldehyde gels depend not only on the composition of reaction mixtures and duration of the high temperature treatment but also on the manner and period of reagent mixing (a hitherto overlooked synthesis step), as different amounts of alternatively substituted resorcinol can be produced before heat treatment commences. (C) 2017 Elsevier Ltd. All rights reserved.