WATER PERMEATION MEASUREMENTS (1)
The type of polyisocyanurates has a great influence on the absorbed water volume:
- the coatings obtained from HDI absorb more water than the corresponding IPDI compositions, despite their higher fluorine percentages. This is probably due to the rubbery character of the HDI coatings, which are characterized by TgH values lower than those of the IPDI coatings and lower than the ambient temperature in many cases.