A process comprising a) carrying out the polymerization of tetrafluoroethylene and at least one comonomer comprising a functional group by an aqueous dispersion polymerization process in a vessel in the presence of a dispersing agent and a polymerization initiator, upon agitation and under autogenous TFE pressure of 10-40 kg/cm 2 to form a functional TFE copolymer fine powder resin, wherein the addition of the comonomer to the vessel is controlled to assure that the comonomer is essentially completely reacted or consumed before the polymerization is 80-90% complete, and the TFE is polymerized for the final 10-20% of the polymerization in the absence of comonomer; b) expanding the functional TFE copolymer fine powder resin to form an expanded TFE copolymeric material having functional groups and a microstructure characterized by nodes interconnected by fibrils; and c) reacting the functional groups after the step of expanding the functional TFE copolymer to change a chemical or physical property of the expanded functional TFE copolymer material, wherein the at least one comonomer having functional groups is a compound having the general formula CX 2 =CXZ, CX 2 =CX-R-Z, or CF 2 =CF-OR f Z, wherein X is H, halogen, alkyl, or fluoroalkyl; R is alkyl, alkyl ether, fluoroalkyl ether, or perfluoroalkyl ether; R f is fluoroalkyl, or fluoroalkyl ether; and Z is selected from the group consisting of: alcohols -C-OH; aldehydes -CHO; ketones -C=O; carboxylic acids -COOH or salts; esters -COOR or -OCOR, where R is alkyl or aryl group; cyano or nitriles -CN; amines -C-NH 2, -C-RNH, or -C-R 2 NR 1. where R, R 1, and R 2 are alkyl or fluoroalkyl; amide -C NH 2 or -C N(R 1)(R 2), where R 1 and R 2 are alkyl or fluoroalkyl; carbonyl halide -XC=O where X is F or Cl; sulfonyl halide -S0 2 X where X is F or Cl; sulfonic acid -S0 3 H or salts; sulphonamide -S0 2 NH 2; sulfonimide -SO 2 -N H N-SO 2 -; anhydrides -C -O- C-; carbamates O=CONH-; sulfides C-S-C; cyanate -O-CN; phosphonic O-P(=O)OH 2; triazine amidine -C(=NH)-NH 2; or isocynate -N=C=O, and wherein the functional TFE copolymer fine powder resin further comprises at least one additional melt-processable fluoropolymer. a) carrying out the polymerization of tetrafluoroethylene and at least one comonomer comprising a functional group by an aqueous dispersion polymerization process in a vessel in the presence of a dispersing agent and a polymerization initiator, upon agitation and under autogenous TFE pressure of 10-40 kg/cm 2 to form a functional TFE copolymer fine powder resin, wherein the addition of the comonomer to the vessel is controlled to assure that the comonomer is essentially completely reacted or consumed before the polymerization is 80-90% complete, and the TFE is polymerized for the final 10-20% of the polymerization in the absence of comonomer; b) expanding the functional TFE copolymer fine powder resin to form an expanded TFE copolymeric material having functional groups and a microstructure characterized by nodes interconnected by fibrils; and c) reacting the functional groups after the step of expanding the functional TFE copolymer to change a chemical or physical property of the expanded functional TFE copolymer material, X is H, halogen, alkyl, or fluoroalkyl; R is alkyl, alkyl ether, fluoroalkyl ether, or perfluoroalkyl ether; R f is fluoroalkyl, or fluoroalkyl ether; and Z is selected from the group consisting of: alcohols -C-OH; aldehydes -CHO; ketones -C=O; carboxylic acids -COOH or salts; esters -COOR or -OCOR, where R is alkyl or aryl group; cyano or nitriles -CN; amines -C-NH 2, -C-RNH, or -C-R 2 NR 1. where R, R 1, and R 2 are alkyl or fluoroalkyl; amide -C NH 2 or -C N(R 1)(R 2), where R 1 and R 2 are alkyl or fluoroalkyl; carbonyl halide -XC=O where X is F or Cl; sulfonyl halide -S0 2 X where X is F or Cl; sulfonic acid -S0 3 H or salts; sulphonamide -S0 2 NH 2; sulfonimide -SO 2 -N H N-SO 2 -; anhydrides -C -O- C-; carbamates O=CONH-; sulfides C-S-C; cyanate -O-CN; phosphonic O-P(=O)OH 2; triazine amidine -C(=NH)-NH 2; or isocynate -N=C=O,