Synthesis and characterization of novel polysiloxane-grafted fluoropolymers

Abstract

Fluorosilicone polymers combine the properties of both fluorocarbons and siloxanes, yielding materials with unique properties. Novel crosslinked fluorosilicone polymers were synthesized by grafting diisocyanate-terminated polydimethylsiloxane (PDMS) to hydroxyl-functionalized fluoropolymers of poly(tetrafluoroethylene-co-vinyl acetate-co-vinyl alcohol) (PTFE-VAc-VA), as confirmed by elemental bulk and surface analysis. The fluorosilicone polymers containing 34 mol% of TFE were thermally stable with a degradation temperature of 267 °C. Fluorosilicone films were found to be more hydrophobic than the parent, non-grafted fluoropolymers; dynamic advancing and receding water contact angles for PTFE-co-VAc-co-VA-g-PDMS were 104° ± 1° and 61° ± 1°, respectively, whereas for PTFE-co-VAc they were 90° ± 2° and 59° ± 2°. The combined properties of thermal stability and hydrophobicity suggest that these fluorosilicones may be useful for coating and paint applications.Key words: fluoropolymers, fluorosilicone, polydimethylsiloxane, supercritical carbon dioxide.

Fluorosilicones and Other Fluoropolymers

“…[39]. To overcome this void in thermal stability, Baradie et al [43] synthesized fluorosilicone polymers consisting of a fluorocarbon backbone and siloxane pendant groups, where urethane chemistry was used for grafting; the structure of the polymer is shown in Scheme 6.9. Suzuki et al [41] grafted PDMS onto a poly(chlorotrifluoroethylene) (CTFE) via an epoxide, but this ether bond was non-ideal, with a low cohesion energy of 4.2 kJ/mol compared with a urethane bond at 36.5 kJ/mol [41,42].…”

“…[40]; (b) polydimethylsiloxane with an epoxide end group grafted onto a fluoropolymer, taken from Ref. [43]. [43].…”

The Preparation and Properties of Fluoroacrylate-Modified Polysiloxane as a Fabric Coating Agent

“…Currently, concerning fluoropolymer-modified polysiloxane materials, preparation methods mainly include hydrosilylation, emulsion polymerization, atom transfer radical polymerization (ATRP), photopolymerization, and grafting methods [6][7][8][9][10][11][12][13][14]. Furukawa et al [6,7] utilized the hydrosilylation of fluorinated olefins with polyhydromethylsiloxane to synthesize a series of fluorosilicones and used them hydrosilylation of fluorinated olefins with polyhydromethylsiloxane to synthesize a series of fluorosilicones and used them as finishing agents for polyester fabrics.…”

Polydimethylsiloxane- (PDMS-) Grafted Fluorocopolymers by a “Grafting through” Strategy Based on Atom Transfer Radical (Co)polymerization

“…Fluoropolymers and polysiloxanes are important types of polymers with useful properties. In general, fluoropolymers have low surface energy, low coefficient of friction, excellent dielectric properties and weatherability, and considerable solubilities in supercritical carbon dioxide. − Polysiloxanes are thermally stable and elastomeric, with low surface energy and high gas permeability. − With exceptionally good chemical, thermal, and thermooxidative resistance, fluorosilicones (i.e., fluorinated polysiloxanes) have been used as commercial high-temperature lubricants and elastomers. − Moreover, a variety of complex polymers consisting of fluoropolymer and polysiloxane building blocks have also been prepared for the development of new types of polymer materials with excellent properties. − For instance, Baradie and Shoichet synthesized graft copolymers with a fluorinated backbone and polydimethylsiloxane (PDMS) grafts by conventional radical copolymerization via a “grafting through” approach and used the thermoplastic graft copolymers for the preparation of hydrophobic and thermally stable coatings …”

“…All these copolymers were prepared based on the ATRP technique via a “grafting through” approach using methacryloxypropyl-terminated PDMS (PDMSMA) as the macromonomer. − The copolymers 1 , with a linear fluorinated backbone and linear PDMS grafts, were prepared by atom transfer radical copolymerization (ATRCP) of 2,3,4,5,6-pentafluorostyrene (PFS) with PDMSMA. In contrast to polymers reported with similar grafting features, − 1 possesses poly(PFS)-based backbones having reactive pentafluorophenyl functionalities that allow for further derivatization, chain growth, and cross-linking. ,, The copolymers 2 , with a hyperbranched fluorinated backbone and linear PDMS grafts, were prepared by atom transfer radical self-condensing vinyl copolymerization (ATR−SCVCP) of an inimer, p -chloromethylstyrene (CMS), with PFS and PDMSMA. The copolymers 3 , having HBFP-based cores and linear PDMS chains, were prepared by ATRP of PDMSMA initiated by HBFP containing benzylic chloride functionalities .…”