Use Of New Renewable Resource For Low VOC Enamel
and cause the change in size-distribution
of water droplets. The first mechanism is
coalescence where fusion of two or more
droplets forms a single larger droplet
by rupturing the films of the continuous
oil phase. The other way destabilization
can occur is if molecules of the dispersed
phases have a relatively higher solubility
in the continuous phase. The smaller the
sizes of the dispersed phase, the less will
be the tendency to sediment due to lower
gravitational pull.
Performance of preserved Sweet Sap
(Trials 1 and 2) was evaluated after 10
months against Additive 1 and Additive
2 (similar commercially available emulsifiers). Both the standard additives and the
trial additive show better stability compared to the emulsion without additive
(Figure 9). Trial 2 showed slightly better
stability in terms of syneresis possibly because of higher viscosity compared to the
other samples.
The graphical representation in Figure 10
shows the extent of syneresis of different
emulsions for a period of 18 days kept
in a measuring cylinder. Initial viscosity
measured before testing is also indicative
of the trend to separate out as intial low
vicosity has greater tendency towards
syneresis.
The stability of the emulsion based
on the extent of syneresis, as is evident
from Figure 10, is also reflected in the final paint. The paint sample made with
trial Sweet Sap kept in an incubator for 96
hours at 60 0C shows more resilience than
standard product and product made without emulsifier as is shown in Figure 11.
As stated earlier, the experiments have
also been extended for co-grind colored
systems like Blue (Phiroza Blue) and Grey
(Smoke Grey). The samples of Phiroza
Blue made without emulsifier, with commercially available additives and with
experimental additive were tested for
pigment flocculation, reversal of grinding and drop in viscosity. These tests were
conducted after a period of ten months
with the samples which were kept at room
temperature and evaluated against a sample initially kept in an incubator for 96
hours at 60 0C. Samples without emulsifier show significant pigment flocculation
which is visible from the drawdown. The
Figure 7: Extent of vehicle separation of the emulsion after seven days storage in a measuring cylinder.
Figure 8: Distribution of water micelles with and without emulsifier.
Figure 9: Emulsions with standard additives, trial additive and emulsion without additive.
