Chemistry Reference
In-Depth Information
Rubber 4.8%
Printing 3.7%
Coating 12.9%
Soap 43.9%
Paper making 35.2%
Figure 5.2
Gun rosin usage in industry, the data adapted from reference [63]
Most rosin soaps have water-loving carboxylate groups, and the remainder of the
rosin molecule has a water-hating hydrocarbon group. The rosin soap exists as
micelles in solution, and the groups of soap molecules associate with each other so
that the water-hating parts face each other to avoid contact with water. Aluminum
compounds are needed for paper making furnish. Aluminum ions react with the
carboxylate groups in the rosin, which causes the rosin to precipitate on to the fibre
surface. The recommended pH conditions for rosin soap sizing are dictated by the
effect of pH on the predominant species of the aluminum ions. Low pH conditions
favour the presence of trivalent aluminum, a hydrated form of Al
3+
.
This is the species
that appears to be most useful for the retention and setting of rosin soap size [64].
Rosin soaps are designed for use as an emulsifier in the polymerisation of styrene-
butadiene rubber and other synthetic rubbers. It was used for the polymerisation
of styrene-butadiene rubber emulsifiers. When dispersed in the aqueous phase of
the monomer emulsion they facilitate micelle formation, thereby forming stable
monomers. Rosin calcium soap is used in paints. Lead, cobalt and manganese have
been used traditionally as driers in these paints.
5.4.2 Antibacterial Activity
The antibacterial activity of rosin-based surfactants has been mostly focused on
cationic surfactants (quaternary ammonium salts). Quaternary ammonium salts
are frequently used as antibacterial agents because they can disrupt cell membranes
