| 脲醛树脂化学结构及反应的13C-NMR研究 |
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| 引用本文： | 韩书广,吴羽飞.脲醛树脂化学结构及反应的13C-NMR研究[J].南京林业大学学报(自然科学版),2006,30(5):15-20. |
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| 作者姓名： | 韩书广 吴羽飞 |
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| 作者单位： | 南京林业大学木材工业学院,江苏,南京,210037 |
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| 基金项目： | 南京林业大学校科研和教改项目 |
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| 摘 要： | 通过13C-NMR可以很好地解析采用传统工艺(碱—酸—碱工艺)合成脲醛树脂反应过程中的结构变化,并可推测可能发生的反应。研究表明:碱性条件下,甲醛与尿素的反应以加成反应为主,反应生成大量的一羟甲脲,尿素全部参与反应,甲醛此时以聚合状态存在,同时伴有缩聚反应的发生;酸性反应阶段以缩聚反应为主,形成以亚甲基键或醚键联接大分子体系,聚合状态的甲醛已全部分解,并以甲二醇的形式参与缩聚反应;第3次尿素的加入可以明显地降低反应体系中的游离甲醛含量,同时主要生成为一羟甲脲。
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| 关 键 词： | 脲醛树脂 化学位移 化学结构 |
| 文章编号： | 1000-2006(2006)05-0015-06 |
| 收稿时间： | 2005-11-14 |
| 修稿时间： | 2006-06-17 |
A Study on Chemical Structure and Reaction of Urea-formaldehyde Resin by 13C-NMR Spectrometry |
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| HAN Shu-guang,WU Yu-fei.A Study on Chemical Structure and Reaction of Urea-formaldehyde Resin by 13C-NMR Spectrometry[J].Journal of Nanjing Forestry University(Natural Sciences ),2006,30(5):15-20. |
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| Authors: | HAN Shu-guang WU Yu-fei |
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| Institution: | College of Wood Science and Technology Nanjing Forestry University, Nanjing 210037, China |
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| Abstract: | The very good method to analyze the structural change of reaction process of UF resin synthesized by the traditional process alkali-acid-alkali is ~(13)C-NMR,and it may extrapolate the possible reaction.The structure analysis indicated that,under alkalinity condition,formaldehyde and urea reacted by addition reaction was primary.The reaction production was mainly monomethylolurea.The urea participated in the reaction completely.The formaldehyde this time still had existence by polymerization,at the same time had the occurrence of polycondensation reaction.At the acid reaction stage the polycondensation reaction was primary and formed the macro-molecule system with the methylene or the ether linkage,and the polymerization formaldehyde decomposed completely,and as the form of methylene glycol participated in condensation reaction. The third urea joined may obviously reduce the free formaldehyde content of the reacting system,at the same time the reaction production was mainly monomethylolurea. |
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| Keywords: | 13C-NMR |
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