Studies on Unstable Structures in Urea\-ormaldehyde Resins Prepared in Strong Acid Medium

Chem. J. Chinese Universities

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Studies on Unstable Structures in Urea\-ormaldehyde Resins Prepared in Strong Acid Medium

LI Ai-Ping, KAN Cheng-You, DU Yi, LIU De-Shan

Institute of Polymer, Department of Chemical Engineering, Key Laboratory of Advanced Materials of Ministry of Education, Tsinghua University, Beijing 100084, China

Received:2005-12-12 Revised:1900-01-01 Online:2006-09-10 Published:2006-09-10
Contact: LIU De-Shan

Abstract

Abstract: The variations of unstable structures in the synthesized urea-formaldehyde (UF) resin systems with the change of the molar ratios of formaldehyde to urea were discussed by ¹³C NMR spectroscopy. The results show that the relative contents of dimethylene ether groups, methylols and unreactive formaldehyde increased gradually with the increase of the molar ratios of formaldehyde to urea from 0.5 to 3.0, which implied that the structure of UF resins can be optimized by controlling the molar ratios of formaldehyde to urea in the process of synthesizing UF resin. It is optimal for the molar ratios of formaldehyde to urea in the range of 1.5 to 2.0, as evidenced by small amounts of unstable structures and significant amounts of stable structures in UF resins prepared.

Key words: Urea-formaldehyde resin, Unstable structure, 13C NMR, Molar ratio

CLC Number:

O631

TrendMD:

LI Ai-Ping, KAN Cheng-You, DU Yi, LIU De-Shan. Studies on Unstable Structures in Urea\-ormaldehyde Resins Prepared in Strong Acid Medium[J]. Chem. J. Chinese Universities, doi: .

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Studies on Unstable Structures in Urea\-ormaldehyde Resins Prepared in Strong Acid Medium

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