Results 251 to 260 of about 106,553 (284)

Formaldehyde levels in homes insulated with urea-formaldehyde foam

Environmental Monitoring and Assessment, 1982
Twenty seven UFFI homes in Colorado and Wisconsin were sampled for formaldehyde levels. The formaldehyde concentrations found in these homes averaged 0.059 ppm. Two homes were monitored for an extended period to determine the impact of ambient climatic conditions.
W C, Schutte, R S, Cole, K R, Long, C W, Frank   +3 more
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Urea–Formaldehyde and Melamine–Formaldehyde Polymers

1989
According 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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Urea–formaldehyde resin prepared with concentrated formaldehyde

Journal of Adhesion Science and Technology, 2016
AbstractThe characteristics of UF resin prepared with concentrated formaldehyde were studied in this paper. With the molar ratio F/U = 1.1, the UF resin prepared with concentrated formaldehyde showed better mechanical properties than that with formalin. The 13C-NMR and FTIR results indicated that there were more methylene groups, ether groups and urons
Zhigang Wu, Hong Lei, Guanben Du, Ming Cao, Xuedong Xi, Jiankun Liang   +5 more
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Pyrolysis of melamine–formaldehyde and urea–formaldehyde resins

Journal of Applied Polymer Science, 1991
AbstractPyrolysis 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, Sumire Kawamoto, Akio Okuro   +2 more
openaire   +1 more source

Epoxy resin modified urea formaldehyde and silicon urea formaldehyde as microwave absorbers

2008 International Conference on Recent Advances in Microwave Theory and Applications, 2008
In 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, V.K. Kokate, A.A. Athawale, M.H.M. Alhousami   +3 more
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Modification of the hardener of urea formaldehyde resins with a low molar ratio of formaldehyde to urea

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.
openaire   +1 more source

Comparison of the properties of urea-formaldehyde resins by the use of formalin or urea formaldehyde condensates

Journal of Adhesion Science and Technology, 2018
In industry, formalin and urea formaldehyde condensates (UFC) are used for the preparation of urea-formaldehyde adhesives. The aim of this study was to evaluate the characteristics of a UF resin prepared with formalin (42% concentration) and two kinds of UFC with various urea content (F/U ∼ 5 and 4.3 malar ratio).
Dorieh, Ali, Mahmoodi, Nosratollah, Mamaghani, Manouchehr, Pizzi, Antonio, Mohammadi Zeydi, Massoud   +4 more
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Colloidal aggregation of aminoplastic polycondensation resins: Urea–formaldehyde versus melamine–formaldehyde and melamine–urea–formaldehyde resins

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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Reactions of molten urea with formaldehyde

Industrial & Engineering Chemistry Product Research and Development, 1985
Etude par chromatographie phase liquide haute performance de la reaction du titre.
Thomas P. Murray, Ernest R. Austin, Robert G. Howard, Timothy J. Bradford   +3 more
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Formaldehyde and urea formaldehyde cavity wall insulation

Structural Survey, 1984
Formaldehyde 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.
openaire   +1 more source