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首页> 外文期刊>Journal of Applied Polymer Science >The Curing of UF Resins Studied by Low-Resolution ~1H-NMR
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The Curing of UF Resins Studied by Low-Resolution ~1H-NMR

机译：低分辨〜1H-NMR研究超滤树脂的固化

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摘要

A series of UF resins and one MUF resin were studied by low-resolution ~1H-NMR. The mobility of the resin during curing could be followed by measuring the spin-spin relaxation time (T_2) with curing time. The relative curing behavior was similar to that found by traditional gel time measurements. In addition, extra features in the T_2 plots with curing time time showed at what point the bulk of the condensation reactions took place. The speed of cure was also related to the chemical groups in the liquid resin, and it was found that the linear methylol groups were mainly responsible for the curing speed of the resins. By studying the curing with different hardener levels and glue concentrations it was found that a UF resin is more sensitive to the glue mix concentration than an MUF resin. A cured resin was also studied after curing to investigate postcuring effects. Water seemed to play the biggest role in the postcure, with substantial amounts pressent immediately after cure, whcih decreased with curing time and aging. For the low mol ratio resins studied here further curing reactions did not seem to play a major role in the post curing phenomenon.
机译：通过低分辨〜1H-NMR研究了一系列的UF树脂和一种的MUF树脂。固化过程中树脂的迁移率可以通过测量自旋-自旋弛豫时间（T_2）和固化时间来跟踪。相对固化行为与传统的胶凝时间测量结果相似。此外，T_2图中具有固化时间的其他特征显示了大部分缩合反应发生在什么时候。固化速度还与液态树脂中的化学基团有关，并且发现线性羟甲基基团主要负责树脂的固化速度。通过研究不同固化剂含量和胶水浓度的固化，发现UF树脂比MUF树脂对胶水混合浓度更敏感。固化后还研究了固化树脂以研究后固化效果。水似乎在后固化中起着最大的作用，固化后立即施加大量压力，但随着固化时间和老化而降低。对于此处研究的低摩尔比树脂，进一步的固化反应似乎在后固化现象中没有发挥主要作用。

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