Method for the preparation of nitrated styrenic fluoropolymers

A method for the preparation of a nitrated styrenic fluoropolymer having an average degree of substitution (DS) ranging from about 0.2 to about 1 of the nitro group on the styrenic ring comprising the steps of:

• i. providing a styrenic fluoropolymer having a styrenic unit of:
• wherein R1, R2, and R3 are each independently hydrogen atoms, alkyl groups, substituted alkyl groups, or halogens, wherein at least one of R1, R2, and R3 is a fluorine atom, and wherein R is hydrogen or a substituent on the styrenic ring;
• ii. optionally mixing the styrenic fluoropolymer with an organic solvent;
• iii. mixing the styrenic fluoropolymer of (i) or (ii) with a combination of nitric acid in an amount from about 0.2 to about 5 moles per styrenic unit and sulfuric acid in an amount from about 1 to about 20 moles per styrenic unit;
• and
• iv. reacting the mixture of (iii) for a period of time to obtain the nitrated styrenic fluoropolymer having an average DS of from about 0.2 to about 1 of the nitro group.