2 2 2 tetrafluorooethoxy 1 1 2 2 tetrafluoroethanesulfonyl fluoride str7 the proportion of dioxole in the amorphous terpolymers of this invention should preferably be at least 12 mole percent of the tetrafluoroethylene content while the mole percent content of the third monomer should be the smallest of all three monomers outside these limits either an amorphous terpolymer may not be obtained or if made its maximum tensile modulus and strength may not be realized copolymerization is carried out in the presence of a free radical generator preferably at a slightly elevated temperature for example 55 u00b0 65 u00b0 c well agitated pressure equipment should be used in addition to tetrafluoroethylene amorphous copolymers may be fabricated from the dioxole and chlorotrifluoroethylene vinylidene fluoride hexafluoropropylene trifluoroethylene perfluoro alkyl vinyl ethers of the formula cf 2 u2550 cfor f where r f is a normal perfluoroalkyl radical having 1 3 carbon atoms fluorovinyl ethers of the formula cf 2 u2550 cfoqz where q is a perfluorinated alkylene radical containing 0 5 ether oxygen atoms wherein the sum of the c and o atoms in q is 2 to 10 and z is a group selected from the class consisting of cn cof and och 3 where r is a c l c4 alkyl vinyl fluoride and perfluoroalkyl ethylene r f ch u2550 ch 2 where r f is a c l c8 normal perfluoroalkyl radical the maximum preferred mole percentage of the comonomer in the copolymers are as follows without further elaboration it is believed that one skilled in the art can using.