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Phenolic and tannin‐based adhesive resins by reactions of coordinated metal ligands. II. Tannin adhesive preparation, characteristics, and application
Author(s) -
Pizzi A.
Publication year - 1979
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.1979.070240511
Subject(s) - tannin , formaldehyde , metal ions in aqueous solution , adhesive , metal , curing (chemistry) , chemistry , steric effects , phenol , materials science , polymer chemistry , organic chemistry , nuclear chemistry , food science , layer (electronics)
The accelerating effect due to bivalent metal ions observed in simple phenol–formaldehyde reactions are also observed in tannin–formaldehyde resins. Tannin steric hindrance prevents the retarding effect of trivalent metallic ions on tannin–formaldehyde reactions. Small amounts of metal ions do not significantly increase flavonoid B‐ring participation to the crosslinking of tannin–formaldehyde networks. Improved plywood strength and shorter pressing times are obtained by the addition of metal ions to tannin/formaldehyde resins. These results are due to faster curing promoted by the presence of the metal ions.