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Curing behavior of anionic poly(urethane urea) dispersions crosslinked with partially methylated melamine formaldehyde
Author(s) -
Chiu HsienTang,
Huang YiChin,
Chiang ChihHsin
Publication year - 2007
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.26520
Subject(s) - curing (chemistry) , materials science , urea formaldehyde , polymer chemistry , thermogravimetric analysis , melamine , formaldehyde , composite material , chemical engineering , chemistry , organic chemistry , adhesive , layer (electronics) , engineering
A rigid‐body pendulum rheometer was used to observe the isothermal cure behavior of an anionic poly(urethane urea) dispersion crosslinked with different amounts of partially methylated melamine formaldehyde (PMMF). In this experiment, the anionic poly(urethane urea) dispersion had a large number of >NH crosslinking or branching sites in urethane and urea groups per molecule, which allowed a large amount of PMMF to couple with the elastic polyurethane (PU) backbone. The test results showed that the cure response of the PU dispersion crosslinked with PMMF was a function of the concentration of PMMF and indicated that 30 phr PMMF could be the optimum amount of the crosslinking agent and that 120°C was the optimum temperature for the curing process. In addition, PMMF self‐condensation could take place during the curing process. The self‐condensation of PMMF also was monitored by a thermogravimetric method. Moreover, the dynamic mechanical properties of PMMF‐crosslinked PU films were affected by the concentration of PMMF. From the curing behavior and dynamic mechanical analysis test results, it was reasonable to assume that highly PMMF branched PUs with partial crosslinking structures could be formed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007