Perfluoroelastomer compositions and methods of preparing same

A curable perfluoroelastomeric composition comprising:

• a first curable perfluoropolymer comprising tetrafluoroethylene, a first perfluoroalkylvinyl ether and at least one first cure site monomer having a cure site, wherein a molar ratio of the tetrafluoroethylene to the perfluoroalkylvinyl ether is about 0:100 to about 65:35 molar percentage in the perfluoropolymer;
• a second curable perfluoropolymer comprising tetrafluoroethylene, a second perfluoroalkylvinyl ether which may be the same or different from the first perfluoroalkylvinyl ether, and at least one second cure site monomer having a cure site which may be the same or different from the at least one first cure site monomer, wherein a molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether is about 65:35 to about 95:5 in the polymer and wherein when the first and second curable perfluoropolymers include the same monomers, the molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether in the second curable perfluoropolymer is different from the molar ratio of the tetrafluoroethylene to the first perfluoroalkylvinyl ether of the first curable perfluoropolymer;
• and
• at least one curative capable of curing the at least one first cure site monomer and the at least one second cure site monomer, wherein the subtracted difference in molar percentage content between the first perfluoroalkylvinyl ether and the second perfluoroalkylvinyl ether is about 5% to about 25% and wherein the weight percentage ratio of the first perfluoropolymer to the second perfluoropolymer in the composition is about 65:35 to about 35:65.

A cured perfluoroelastomeric composition, comprising:

• a first perfluoroelastomer formed from a first curable perfluoropolymer comprising tetrafluoroethylene, a first perfluoroalkylvinyl ether and at least one first cure site monomer having a cure site, wherein a molar ratio of the tetrafluoroethylene to the perfluoroalkylvinyl ether is about 0:100 to about 65:35 molar percentage in the perfluoropolymer;
• and
• a second perfluoroelastomer formed from a second curable perfluoropolymer comprising tetrafluoroethylene, a second perfluoroalkylvinyl ether which may be the same or different from the first perfluoroalkylvinyl ether, and at least one second cure site monomer having a cure site which may be the same or different from the at least one first cure site monomer, wherein a molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether is about 65:35 to about 95:5 in the second curable perfluoropolymer and wherein when the first and second curable perfluoropolymers include the same monomers, the molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether in the second curable perfluoropolymer is different from the molar ratio of the tetrafluoroethylene to the first perfluoroalkylvinyl ether of the first curable perfluoropolymer, wherein the cured composition has a compression set of less than 25% at 70 hours at 300° C. and are plasma resistant upon exposure to NF3 plasma.

A method for making a cured perfluoroelastomeric composition comprising:

• (a) preparing a curable perfluoroelastomeric composition by combining:
• (i) a first curable perfluoropolymer comprising tetrafluoroethylene, a first perfluoroalkyl vinyl ether and at least one first cure site monomer having a cure site, wherein a molar ratio of the tetrafluoroethylene to the first perfluoroalkyl vinyl ether is about 0 to about 100 to about 65:35 in the perfluoropolymer;
• (ii) a second curable perfluoropolymer comprising tetrafluoroethylene, a second perfluoroalkylvinyl ether which may be the same or different from the first perfluoroalkylvinyl ether, and at least one second cure site monomer having a cure site which may be the same or different from the at least one first cure site monomer, wherein a molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether is about 65:35 to about 95:5 in the polymer and wherein when the first and second curable perfluoropolymers include the same monomers, the molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether in the second curable perfluoropolymer is different from the molar ratio of the tetrafluoroethylene to the first perfluoroalkylvinyl ether of the first curable perfluoropolymer;
• and
• (iii) at least one curative capable of curing the cure site of the at least one first cure site monomer and the cure site of the at least one second cure site monomer;
• and
• (b) curing the first and second curable perfluoropolymers in the perfluoroelastomeric composition to form a cured perfluoroelastomeric composition, wherein the cured composition has a compression set of less than 25% at 70 hours at 300° C. and are plasma resistant upon exposure to NF3 plasma.

A curable perfluoroelastomeric composition comprising:

• a first curable perfluoropolymer comprising tetrafluoroethylene, a first perfluoroalkylvinyl ether and at least one first cure site monomer having a cure site, wherein a molar ratio of the tetrafluoroethylene to the perfluoroalkylvinyl ether is about 0:100 to about 65:35 molar percentage in the perfluoropolymer;
• a second curable perfluoropolymer comprising tetrafluoroethylene, a second perfluoroalkylvinyl ether which may be the same or different from the first perfluoroalkylvinyl ether, and at least one second cure site monomer having a cure site which may be the same or different from the at least one first cure site monomer, wherein a molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether is about 65:35 to about 95:5 in the polymer, and wherein when the first and second curable perfluoropolymers include the same monomers, the molar ratio of the tetrafluoroethylene to the second perfluoroalkylvinyl ether in the second curable perfluoropolymer is different from the molar ratio of the tetrafluoroethylene to the first perfluoroalkylvinyl ether of the first curable perfluoropolymer;
• and
• at least one curative capable of curing the at least one first cure site monomer and the at least one second cure site monomer, wherein the composition comprises from about 0.6 to about 0.9 weight percentage of the curative, wherein the weight percentage ratio of the first perfluoropolymer to the second perfluoropolymer in the composition is about 65:35 to about 35:65 and the subtracted difference in molar percentage content between the first perfluoroalkylvinyl ether and the second perfluoroalkylvinyl ether is about 5% to about 25% and, wherein, upon cure, the cured compositions have a compression set of less than 25% at 70 hours at 300° C. and are plasma resistant upon exposure to NF3 plasma.