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A rheological study of the gelling of UF polycondensates
Author(s) -
Halász L.,
Vorster O.,
Pizzi A.,
Alphen J. Van
Publication year - 2000
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/(sici)1097-4628(20000307)75:10<1296::aid-app11>3.0.co;2-f
Subject(s) - rheology , urea formaldehyde , curing (chemistry) , activation energy , materials science , polymer chemistry , gel point , molar ratio , molar mass , chemistry , thermodynamics , chemical engineering , composite material , catalysis , organic chemistry , polymer , physics , adhesive , layer (electronics) , engineering
The gelling process of urea–formaldehyde resins has been investigated by rheological methods. The gel point values were determined by three methods, and compared with those obtained by low resolution impulsional 1 H‐nuclear magnetic resonance. The activation energy of the curing process was determined and the effect of the molar ratio was investigated. In addition, the critical power exponents were calculated and the parameters of the relaxation modulus function were also determined. Equations describing the gel time as a function of degree of conversion and reactants molar ratio are presented. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1296–1302, 2000