Premium
Alkaline PF resins linear extension by urea condensation with hydroxybenzylalcohol groups
Author(s) -
Pizzi A.,
Stephanou A.,
Antunes I.,
De Beer G.
Publication year - 1993
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.1993.070501221
Subject(s) - urea , chemistry , formaldehyde , urea formaldehyde , molar ratio , polymer chemistry , condensation reaction , organic chemistry , catalysis , adhesive , layer (electronics)
The linear increase of phenol–formaldehyde (PF) resins by reaction under alkaline conditions of the ortho‐ and para‐hydroxybenzylalcohol groups of the PF resin with small molar percentages of urea was followed by model compounds reactions. Apparent rate constants of the reactions of urea with o ‐and p ‐hydroxybenzylalcohols were obtained. Both the ortho‐ and para‐isomerides appeared to react faster with urea than for their autocondensation. The ortho‐isomeride appears to react faster with urea than the para‐isomeride, under alkaline conditions. Autocondensation under alkaline conditions instead appears to be faster in the case of p ‐hydroxybenzylalcohol. The properties of PF resins prepared with the addition of small amounts of urea appear to be consistent with what is observed in the model compounds reactions: Their gel times become faster and viscosity increases with increasing amounts of urea addition. © 1993 John Wiley & Sons, Inc.