Formation of free radicals in the low-temperature fluorination of polymers

Direct fluorination—Useful tool to enhance commercial properties of polymer articles

“…Formation of radicals has been observed even at T = 77 K for a set of polymers (PE, PP, PS, PMMA, PET, PI, etc.) [12,14,37,38]. The kinetics of formation of radicals ''in situ'' at 77 K is shown in Fig.…”

“…34,000 and 234,000, Aldrich), polyvinyltrimethylsilane (PVTMS) (m.w. 10 6 , Russia), PMMA (produced by gamma-initiated polymerization, Russia), poly(4-methyl-pentene-1), polyimide (PI) Matrimid 5218 1 (CIBA-GEYGI), low-density polyethylene (LDPE) (density 0.918 and 0.926 g cm À3 , Aldrich), high-density polyethylene (HDPE) (industrially available with density 0.945, 0.947, 0.948, 0.946 and 0.949 g cm À3 ; first three without carbon black and latter two containing carbon black; and one from Aldrich with density 9.50 g cm À3 ), polysulfone UDel 3500, polyetheretherketone (PEEK), polycarbonatesiloxane (Carbosil 1 , Russia), polysulphone-polybuthadiene block-copolymers of different composition (Seragel 1 ) (Russia), PVF (Fluorochem Limited, Derbyshire, UK) and PVDF (Scientific Polymer Products Inc., Ontario, Canada) [12][13][14][15]17,19,20,23,32,[36][37][38][39][40][41][42][43][44][45][46][47][48].…”

“…(3) Oxyfluorination accompanied with the graft polymerization. It is well known that in polymers treated with fluorine-oxygen mixtures, a controlled amount of longliving peroxy radicals is generated [11][12][13][14][15]. Additional modification of a polymer may be carried out by a graft polymerization of several monomers having double bonds, e.g.…”

Enhanced anti-graffiti or adhesion properties of polymers using versatile combination of fluorination and polymer grafting

“…In the current paper, we propose to use the following modification of the direct fluorination called "fluorine initiated grafting of monomers". It was shown previously [2,3,9] that rather large concentration of long-lived radicals (fluororadicals and peroxy RO 2…”

Low-temperature fluorination of fluoro-containing polymers

“…After a further temperature increase, heat release was detected due to fluorine addition. The integral of the heat release at this peak is not large ($1.6 cal/g À1 ) and stops completely at T = 200 K. Formation of radicals during fluorination of natural and synthetic polymers has been studied under relatively low fluorine pressure (30 Torr) at 77 K [10]. It has been reported that homolytic cleavage of chemical bonds followed by free radical formation initiates chain halogenation [6].…”