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Performance and structures of urea-formaldehyde resins prepared with different formaldehyde solutions
Wood Science and Technology ( IF 3.4 ) Pub Date : 2021-07-08 , DOI: 10.1007/s00226-021-01280-y
Gaoxiang Xu 1 , Bengang Zhang 1 , Zhigang Wu 1, 2 , Hong Lei 1 , Guanben Du 1 , Jiankun Liang 3
Affiliation  

Two types of urea–formaldehyde (UF) resin adhesives were synthesized with standard formaldehyde solution with 37% concentration and concentrated formaldehyde solution with 45% concentration. For 37% formaldehyde, 10% methanol was used as an inhibitor. For 45% formaldehyde, no more methanol was added. The chemical structure and changes during the resin preparation were analyzed. The performance of particleboards prepared with these resins was evaluated. The results indicated that the main difference between the concentrated formaldehyde and the standard formaldehyde was the higher content of methanol in the latter. Methanol affected the reaction during the preparation of UF resins and the final performance of the resins. Samples of the UF resin with standard formaldehyde taken at different stages during its preparation showed different contents of methylol groups, methylene ether bonds, uron structure, methylene bonds, and other groups compared to the resin prepared from concentrated formaldehyde. The performance concerning water resistance, mechanical performance, and formaldehyde emission of the particleboards prepared with the UF resin with concentrated formaldehyde was better than that with the resin with standard formaldehyde.



中文翻译:

不同甲醛溶液制备的脲醛树脂的性能和结构

用37%浓度的标准甲醛溶液和45%浓度的甲醛溶液合成了两种类型的脲醛(UF)树脂胶粘剂。对于 37% 的甲醛,使用 10% 的甲醇作为抑制剂。对于 45% 的甲醛,不再添加甲醇。分析了树脂制备过程中的化学结构和变化。评估了用这些树脂制备的刨花板的性能。结果表明,浓缩甲醛与标准甲醛的主要区别在于后者甲醇含量较高。甲醇影响了超滤树脂制备过程中的反应和树脂的最终性能。与由浓甲醛制备的树脂相比,在其制备过程中的不同阶段采集的含标准甲醛的 UF 树脂样品显示出不同的羟甲基、亚甲基醚键、脲醛结构、亚甲基键和其他基团的含量。用浓甲醛超滤树脂制备的刨花板的耐水性、力学性能和甲醛释放量均优于标准甲醛树脂。

更新日期:2021-07-08
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