A method for forming a functionalized fluorine-containing resinous powder comprises providing a fluorine-containing powder having at least one functional group and a compound having at least one reactive functional group reactive with the at least one functional group. A solvent is combined with the fluorine-containing powder and the compound to form a mixture, wherein the fluorine-containing powder is not dissolved in the solvent. One of the at least one reactive functional group of the dissolved compound is reacted with a corresponding one of the at least one functional group from the non-dissolved powder to form the functionalized fluorine-containing resinous powder including at least one of the at least one reactive functional group. The formed functionalized fluorine-containing resinous powder has an average particle diameter of 400 micrometers or less, such as 80 micrometers or less.