Ethylene with hexafluoroacetone copolymerization

Copolymerization of Ethylene with Hexafluoroacetone. Conversion curves at — 78° C for three different initial monomer compositions are... 

Radiation induced copolymerization of hexafluoroacetone xcith a-olefins has been done over a broad temperature range. From these experiments, it was confirmed that ethylene can be copolymerized below its critical temperature to give an alternating copolymer. A radical mechanism is involved at relatively high temperatures below —10°C, the mechanism has been confirmed to be ionic and may be cationic. Propylene can be copolymerized in a way similar to that of ethylene however, the rate of copolymerization was much slower. Isobutylene did not copolymerize with hexafluoroacetone at 0°C. A 1 2 adduct compound was obtained as the main product. At low temperatures, copolymerization proceeds to some extent. 

Copolymerization of Propylene with Hexafluoroacetone. The conversion curves of the copolymerization are shown in Figure 12 as a function of irradiation time for equimolar monomer mixtures at 0°, —35°, and — 78°C. The copolymerization rate is much slower than that of the copolymerization of ethylene and hexafluoroacetone. We have data at... 

Other interesting perfluoro ether stmctures can be obtained by copolymerization of hexafluoroacetone with ethylene oxide, propylene oxide, and trimethylene oxide with subsequent fluorination to yield the following stmctures (67) ... 

The copolymerization of carbonyl monomes with alkenes has been even less studied than that between different carbonhyl monomers. The radiation-initiated copolymerization of styrene with formaldehyde proceeds by a cationic mechanism with a trend toward ideal behavior, r = 52 and r2 = 0 at —78°C [Castille and Stannett, 1966]. Hexafluoroacetone undergoes radiation-initiated copolymerization with ethylene, propene, and other a-olefins [Watanabe et al., 1979]. Anionic copolymerizations of aldehydes with isocyanates have also been reported [Odian and Hiraoka, 1972]. 

Low-temperature, liquid-phase, radiation-induced ( Co y-rays) copolymerization of hexafluoroacetone with ethylene yields the alternating copolymer [(CFs)2C 0 CH2 CH2]re propene appears to behave like its lower homologue in this respect, but the reaction proceeds much more slowly isobutene yields a... 

To prepare Teflon AF series, reactions of hexafluoroacetone (HFA) and ethylene oxide (EO) give rise to defluorinated 2,2-bis(trifluoromethyl)-4,5-difluoro-l,3-dioxole (BDD) monomer, followed by the copolymerization with tetrafluoroethylene (TFE). The physical properties of these amorphous copolymers are dependent upon the compositions in the copolymers as shown in Table 4.8. Currently, there are two commercial grades of Teflon AF polymers produced by DuPont, AF-2400 and AF-1600, which contain the composition of copolymers for which n = 0.87 and 0.65, respectively, where n is the molar ratio of the BDD monomers. 

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