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Blocked melamine–urea–formaldehyde resins and their usage in agglomerated cork panels
Author(s) -
Antunes Ana,
Gomes Ana,
Paiva Nádia,
Ferra João,
Martins Jorge,
Carvalho Luísa,
BarrosTimmons Ana,
Magalhães Fernão D.
Publication year - 2018
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.46663
Subject(s) - melamine , cork , melamine resin , materials science , formaldehyde , urea formaldehyde , caprolactam , tetramine , composite material , fourier transform infrared spectroscopy , synthetic resin , chemical engineering , polymer chemistry , adhesive , chemistry , organic chemistry , layer (electronics) , engineering , metallurgy , coating
Caprolactam and o ‐ p ‐toluenesulfonamide are tested as chain‐growth blockers for melamine–urea–formaldehyde (MUF) resins, in an attempt to reduce the crosslinking density of the cured resin and hence improve its flexibility. Agglomerated cork panels, for which flexibility is a technical demand, were produced with the modified resins and tested. The blockers were added at three different steps in the synthesis process: methylolation, condensation, and at the end of the synthesis. Besides evaluation of standard properties, resins were characterized using gel permeation chromatography and Fourier transform infrared. Blocked resins showed better storage stability and improved water tolerance, especially when caprolactam was employed. When used as binders in agglomerated cork panels, the blocked resins allowed for significantly better flexibility, evaluated in terms of mandrel bending test. The tensile resistance of the panels remained well within the desired limits for this type of material. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46663.