Radiation-induced copolymerization of tetrafluoroethylene and styrene at high pressure

The radiation-induced copolymerization of tetrafluoroethylene (A) and styrene (B) was studied in bulk and in perfluorotoluene at 220C at autogenous pressure and 260 and 510 MPa. The reactivity ratio for addition to A-ended radicals, r/sub A/ is effectively zero at the two lower pressures and is in the range 0.002 to 0.008 at 510 MPa. The other reactivity ratio, r/sub B/, is 6 at autogenous pressure and also at 260 and 510 MPa if the A content of the charge is less than 50%. If the A content is greater than 95%, r/sub B/ appears to be 100 at pressures of 260 and 510 MPa. The apparent variation in r/sub B/ cannot be explained by invoking a penultimate unit effect for B-ended radicals. Polymerization rates scatter somewhat, but all rates are quite small when the A content of the charge is in the range 95 to 99.8%. Polymers containing as much as 66% A appear to be inherently benzene soluble but frequently contain some gel because of radiation-induced crosslinking after their formation. No very high polymers were formed that contained more than a few percent A, even at high pressure. Features that complicated the study were immiscibility of the liquid monomers, extreme variation of the monomer-copolymer compatibility with charge composition, and freezing of B at high pressure. 5 tables