Due to the nature of the aldol condensation reaction
employed in the in this study, it is possible that some [alpha]-Ketoacid compounds might interfere during the color formation reaction.
In the condensation reaction
of UF resin, methylolureas formed big molecules, containing a lot of active end groups such as hydroxymethy (-C[H.
The effect of the different structures of the reactants was studied at 80 C by varying the substituted aromatic aldehydes with thiophenol for condensation reaction
29) As shown in reference (3), chemical bonding is ensured by hydrolysis and condensation reaction
between hydroxyl functional groups on the metal substrate and hydroxyl/alkoxy counterparts on either the side chains of the methyl phenyl polysiloxane resin or the organo-silane (VTEOS) interlayer.
This fact may be attributed to the induced condensation reaction
between the carboxyl end group of the aminoacid and the--OH groups of the formaldehyde in aqueous acidic solution, thus acting like an anchoring point between the layers and the resin, as previously reported (34).
Figure 2d shows a possible structure derived from the different condensation reactions
involved in the sol-gel process.
RTMS can form poly(silsesquioxane)s through the hydrolysis and condensation reaction
According to the ATR-IR analysis increasing the annealing temperature increases the absorption peak due to the more performed condensation reaction
Especially, the polymer chain grows more rapidly at higher temperature, which was consistent with step- condensation reaction
of low molecular.
So in the presence of potassium fluoride-coated alumina (KF-alumina) , using grinding method, the condensation reaction
of acetyl ferrocene and aromatic aldehyde, which compared with the conventional thermal reaction, resulting in higher yield, shorter reaction time and easier post-processing.
1] decreases with the increase of silica contents, indicating that some of the hydroxyl groups of PVA were involve in condensation reaction
with silanol groups, forming covalently bonded crosslinks between polymer segment.
The other is chemically polymerizing aniline monomer and then proceeding the condensation reaction
of silica precursors [16, 17, 20-22].