Fundamental Properties of Asphalts and Modified Asphalts, III

KAO Gripper. The minor resonance was not assigned, but is assumed to be due to a dimer of the
2-ethyl hexanol phosphate formed during preparation of the antistrip. The spectra of the Innovalt
W and KAO gripper show partial hydrolysis of the PPA caused by residual water which is
present in the antistrip agents. This is shown by the increase of the phosphoric acid resonance at
~1.7 ppm relative to the phosphate ester resonance at ~0.7 pm with time of setting.
There do not appear to be any reactions between the Innovalt W and KAO Gripper phosphate
ester antistrip agents and PPA. Presumably, there would not be any such reactions when the
antistrip and PPA were added to asphalt. To test this assumption, Innovalt W and KAO Gripper
antistrips were added to asphalt AAM followed by PPA (115%) addition (figure 2-5.7). Both the
antistrips and PPA were added at a level of 1 wt %. The purpose of these experiments was
twofold: (1) to determine if 31 P NMR can detect signals at the 1% level in a reasonable amount
of time, and (2) to determine if there might possibly be reactions between the PPA and antistrip
in asphalt.
In the case of the phosphate ester antistrip agents, there is a single resonance at a chemical shift
(~1.7 ppm) near that of phosphoric acid (~1.4.ppm). In both cases spectra with reasonable
signal-to-noise, S/N, ratios were obtained after 3 h of signal averaging. When added to asphalt
in the presence of PPA, the ester antistrip resonance could not be resolved from that of
phosphoric acid at the resolution of the WRI magnet. Under high resolution conditions, it is
expected that these resonances could be resolved.
Innovalt W in
PPA (115%)
At 99 h
Innovalt W in
PPA (115%)
at 0 h
Innovalt W neat
30 25 20 15 10 5 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 30 25 20 15 10 5 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50
Phosphorous Chemical Shift, ppm Phosphorous Chemical Shift, ppm
Figure 2-5.6. 31 P NMR spectra of phosphate ester antistrips, neat and with PPA (115%)
at different times.
64
KAO Gripper in
PPA (115%)
At 360 h
KAO Gripper
In PPA (115%)
At 0 h
KAO Gripper neat