Polyurethane Coatings
December 2014 www.coatingsworld.com Coatings World | 37
polycarbonate diol (PCD) in the polyols
mixture and lower NCO/OH ratio value.
The influence of the content of polycarbonate diol in the polyols mixture
can be better observed in the response
surface plots (Figure 6a) and its corresponding curve-level 2D plot (Figure 6b).
Both plots show that the weight loss after abrasion is lower than 40 mg in the
polyurethanes with PCD content higher
than 20wt%, irrespective of the NCO/
OH ratio, and thus the polycarbonate
diol content has a dominant effect on the
abrasion resistance of the polyurethanes.
Furthermore, the response surface and
curve-level 2D plots show that 60wt%
PCD in the polyurethanes produces the
highest abrasion resistance.
Figure 7 shows some optical microscope images of the surfaces of the
polyurethane coatings before and after
abrasion test was carried out. The images
Figure 6. (a): Surface response of abrasion in the polyurethanes as a function of the PCD content and NCO/OH ratio. (b): Curvelevels 2D of the abrasion drawn
over the experimental domain.
Figure 7. Optical microscope images of the
surfaces of the polyurethane coatings before and
after abrasion test. [Photos by José A. Jofre-Reche,
Andrés J. Yáñez-Pacios and José Miguel Martín-Martínez - Adhesion and Adhesives Laboratory –
University of Alicante]
