Poly thiocarbonyl fluoride

Free radical polymerization (with free radicals from the boron alkyl/ oxygen reaction, see Section 20.1.3.1) is also possible at low temperatures. Poly(thiocarbonyl fluoride) is a good elastomer due to its low glass- 

Goethals, Sulfur-containing polymers, J. Macromol. Sci. C Rev. Macromol. Chem.) 2, 73 (1968). 

Gaylord, Polyethers, Pt. 3, Polyalkylene Sulfides and Other Polythioethers, Wiley, London and New York, 1962. 

Hockenberger, Herstellung und Verwendung fester und fliissiger organischer Polysulfid-Polymerer, Chem.-Ing.-Technik 36, 1046 (1964). 

Bertozzi, Chemistry and technology of elastomeric polysulphide polymers. Rubber Chem. Technol. 41, 114 (1968). 

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Above 175° C, poly(thiocarbonyl fluoride) decomposes (63) to regenerate thiocarbonyl fluoride monomer. Chains capped with CF3 are stable to 300° C when heated in nitrogen, though they decompose at 200° C or below when heated in air. Chains so capped have been made by reaction of the polymer with antimony pentafluoride. 

Study of infrared and NMR spectra have established that the end groups in poly(thiocarbonyl fluoride) are CF3S—, —SCF=S, and —SCF=0. All three end groups are present in polymer initiated by dimethylformamide, though —SCF=Q appears to be present in smaller amounts than the other two. Identification of these groups is as follows (64) ... 

Because of its chemical inertness, no direct way of curing poly(thiocarbonyl fluoride) has been found. However, creep has been reduced and strength at elevated temperatures improved by milling into the polymer a free-radical generator, such as dicumyl peroxide or azobisisobutyronitrile, and a free-radical acceptor, such as N,N -m-phenylenebismaleimide or triacryloylhexahydro-s-triazine, and curing with heat and pressure (65). A better method is to mill in divinylbenzene and a small amount of benzoyl peroxide and cure with heat and pressure (66). The divinylbenzene forms a crosslinked matrix that mechanically traps poly(thio-carbonyl fluoride) molecules. Since the elastomer is in effect filled with poly(di-vinyl benzene), the final composition is less resilient than untreated poly(thio-carbonyl fluoride). 

In addition to the elastomers already described, others, have been produced on an experimental scale. These include the perfluoroalkylenetriazines with their unsurpassed thermal oxidative stability for an elastomer but with many offsetting disadvantages, and poly(thiocarbonyl fluoride). It is probably true to say that material does not have any outstanding desirable property that cannot now be matched by an alternative and commercially available material. 

Figure 2.4. Schematic illustrations of repeat units of several of the polymers listed in Table 2.2. (a) Poly(thiocarbonyl fluoride), (b) Poly(glycolic acid), (c) Polyepichlorohydrin. (d) Poly(maleic anhydride), (e) Poly(N-methyl glutarimide). (f) Poly(N-phenyl maleimide). (g) Poly[3,5-(4-phenyl-1,2,4-triazole)-1,4-phenylene]. (h) Phenoxy resin, (i) Poly(oxy-1,4-phenylene-oxy-1,4-phenylene-carbonyl-l,4-phenylene). (j) Udel. (k) Victrex. (1) Tori on. (m) Ultem. (n) Resin F.

W. H. Sharkey, Poly(thiocarbonyl fluoride) and related elastomers, in Polymer Chemistry oj Synthetic Elastomers, Pt. II (J. P. Kennedy and E. G. M. Tornqvist, eds.). Interscience, New York, 1969. 

Poly(thiocarbonyl fluoride) and related fluorothiocarbonyl compounds have been the subject of extensive study in recent years and at least two reviews (Sharkey, 1969 1972) have been devoted to these materials. Commercial production of the material in the near future, however, seems unlikely. 

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