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Journal of Polymers and the Environment, 2020
In view of the fact that a large amount of formaldehyde was involved in the production of urea–formaldehyde fertilizer, and the residual and decomposed formaldehyde has never been paid attention to. In this paper, the determination method of free formaldehyde content in urea–formaldehyde fertilizer was studied.
Yan Liu +8 more
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In view of the fact that a large amount of formaldehyde was involved in the production of urea–formaldehyde fertilizer, and the residual and decomposed formaldehyde has never been paid attention to. In this paper, the determination method of free formaldehyde content in urea–formaldehyde fertilizer was studied.
Yan Liu +8 more
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The reaction of urea with formaldehyde
Recueil des Travaux Chimiques des Pays-Bas, 1952AbstractThe reaction of urea and formaldehyde, giving monomethylolurea, is reversible in a neutral, acid or alkaline aqueous solution, the forward reaction being bimolecular and the reverse reaction monomolecular.The forward and reverse reactions are catalyzed to the same extent by hydrogen ions as well as by hydroxyl ions.
J. I. de Jong, J. de Jonge
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Urea-Formaldehyde Resins and Free Formaldehyde Content
Acta Biologica Hungarica, 1998Specifications of wood adhesives must be in correlation with the requirements for the corresponding wood products, for which they will be used. Formaldehyde emission of wood products bonded with urea-formaldehyde resin based adhesives is strictly regulated by standards and there is a compromise is between formaldehyde emission and performance, such as ...
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Urea–Formaldehyde and Melamine–Formaldehyde Polymers
1989According to Meyer1 the history of urea–formaldehyde (UF) resins can be divided into five different periods: (i) Synthesis of the raw materials urea and formaldehyde. This period started with the synthesis of urea by Wohler in 1824. Formaldehyde was first recognized by Butlerov in 1859 when attempting to synthesize methanediol.
Dietrich Braun, Hans-Josef Ritzert
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Pyrolysis of melamine–formaldehyde and urea–formaldehyde resins
Journal of Applied Polymer Science, 1991AbstractPyrolysis of melamine–formaldehyde and urea–formaldehyde resins in helium and air was investigated by means of TG and gravimetry with isothermal heating, as well as elemental and HCN analyses. Weight loss curves suggest three kinds of reactions involved in the pyrolysis, namely, initiation reactions, reactions splitting off volatile fragments ...
Toshimi Hirata +2 more
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Epoxy resin modified urea formaldehyde and silicon urea formaldehyde as microwave absorbers
2008 International Conference on Recent Advances in Microwave Theory and Applications, 2008In recent days, various microwave absorbers are used for electromagnetic interference and compatibility measurements in anechoic and semi-anechoic chambers. The authors have synthesized three different polymer composites of epoxy resin modified by urea formaldehyde and silicon urea formaldehyde of different wt%.
M. Murugan +3 more
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Известия СПбЛТА, 2023
Для снижения токсичности древесностружечных плит применяют карбамидоформальдегидные смолы с низким мольным соотношением формальдегида и карбамида - 1,0 и менее. Плиты на основе этих смол имеют пониженную прочность и водостойкость и увеличенное время прессования. Указанные недостатки объясняются особенностями новых смол.
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Для снижения токсичности древесностружечных плит применяют карбамидоформальдегидные смолы с низким мольным соотношением формальдегида и карбамида - 1,0 и менее. Плиты на основе этих смол имеют пониженную прочность и водостойкость и увеличенное время прессования. Указанные недостатки объясняются особенностями новых смол.
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Journal of Applied Polymer Science, 2006
AbstractColloidal particles formation followed by their clustering have been shown to be the normal way of ageing of aminoplastic resins, namely urea–formaldehyde (UF) resins, melamine–formaldehyde (MF) resins, and melamine–urea–formaldehyde (MUF) resins. Ageing or further advancement of the resin by other means such as longer condensation times causes
A. Despres, A. Pizzi
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AbstractColloidal particles formation followed by their clustering have been shown to be the normal way of ageing of aminoplastic resins, namely urea–formaldehyde (UF) resins, melamine–formaldehyde (MF) resins, and melamine–urea–formaldehyde (MUF) resins. Ageing or further advancement of the resin by other means such as longer condensation times causes
A. Despres, A. Pizzi
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Curing of urea-formaldehyde resins with a molar ratio of formaldehyde to urea less than one
Известия СПбЛТА, 2022В ходе исследований установлено, что отверждение карбамидоформальдегидных смол (КФС) с образованием пространственно сшитой структуры при мольном соотношении формальдегида к карбамиду менее единицы происходит благодаря образованию инертного соединения – метилендикарбамида (МДК).
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Formaldehyde and urea formaldehyde cavity wall insulation
Structural Survey, 1984Formaldehyde and UF foam cavity wall insulation Urea formaldehyde (UF) foam cavity wall insulation was introduced into this country, from Denmark, in 1959. Relatively little was installed until after the oil crisis which followed the Arab‐Israeli War of 1973. In total, some 1.5 million buildings have been insulated with it.
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