Chemistry Reference
In-Depth Information
Other reactions can also cross-link resins with pendant carboxylic acid groups. For instance, one
can add a melamine formaldehyde condensate:
N
O
2
+
N
N
n
+
n
COOH
O
O
N
N
N
COOH
2
2
O
N
OO
N
N
n
O
N
N
N
O
O
n
A diisocyanate, a phenolic, or a melamine-formaldehyde resin can be used as well. Resins with
pendant hydroxyl groups can also be cross-linked by these materials. A diisocyanate is effective in
forming urethane linkages:
When the pendant groups are epoxides, like glycidyl esters, cross-linking can be carried out
with dianhydrides or with compounds containing two or more carboxylic acid groups [
241
].
Aminoplast resins (urea-formaldehyde or melamine-formaldehyde and similar ones) are also very
effective [
242
].
Pendant amide groups from terpolymers containing acrylamide can be reacted with formaldehyde
to form methylol groups for cross-linking [
243
]:
