As surface coating industry is growing rapidly in these years, studies related with synthesis of new materials are also increasing rapidly. Fluorinated polymers possess a whole range of very interesting bulk and surface properties, such as excellent environmental stability, water and oil repellency, low coefficient of friction, biocompatibility, excellent thermal stability and chemical resistance and low interfacial free energy. Polyisocyanate is one material that could benefit from characteristic properties of fluorinated polymers, as mentioned above. Fluorinated polyurethane is class of new material. However, the high sensitivity of -NCO group towards moisture and its susceptibility to undergo undesirable side reactions makes the use of polyisocyanate with -NCO groups problematic. This problem can be overcome by blocking isocyanate groups with phenols through the formation of carbamate having a labile bond which can dissociate at an elevated temperature to regenerate -NCO functionality. Then the free isocyanate groups are able of reacting with the hydroxyl component during cure.
展开▼
