Poly ethers with fluorinated

Poly(oxyethylene) Ethers with Fluorinated End Groups... 

The inability to process PTFE by conventional thermoplastics techniques has nevertheless led to an extensive search for a melt-processable polymer but with similar chemical, electrical, non-stick and low-friction properties. This has resulted in several useful materials being marketed, including tetrafluoro-ethylene-hexafluoropropylene copolymer, poly(vinylidene fluoride) (Figure 13.1(d)), and, most promisingly, the copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether. Other fluorine-containing plastics include poly(vinyl fluoride) and polymers and copolymers based on CTFE. 

Four poly(ether ketone)s obtained from 2,2-bis[4-(4-fluorobenzoyl)-phenyl]-1,1,1,3,3,3-hexafluoropropane (9) or 2,2-bis[4-(4-fluorobenzoyl)-phenyl]propane (10) with Bisphenol AF (1) or Bisphenol A (4) are all soluble in chloroform, benzene, THF, and aprotic polar solvents such as DMF, DMAc, and NMP.15 Poly(ether ketone) from 9 and 1, which has the highest fluorine content, dissolves easily in ethyl acetate. 

Crystallinity of these hexafluoroisopropylidene-unit-containing poly(ketone)s is low except for poly(sulfide ketone) (13). The water contact angle for the fluorine-containing poly(ketone) films is high, being 98° for poly(ether ketone) (11), from 2,2-bis(4-carboxyphenyl)-l,l, l,3,3,3-hexafluoropropane(15) and 96° for poly(sulfide ketone) (13) from 15, whereas it is 78° for poly(ether ketone) from 2,2-bis(4-carboxy-phenyl)propane (16) and 74° for the poly(sulfide ketone) from 16. This result indicates that the substitution of isopropylidene units of poly-(ketone)s with hexafluoroisopropylidene units has a remarkable effect on the surface properties of poly(ketone) films. 

Diazotization in the presence of boron trifluoride enables diazonium tetrafluoroborates to be isolated from the reaction mixture and purified. Subsequent controlled decomposition produces the required fluoroaromatic. Although explosion hazards and the toxicity of the isolated salts are significant concerns with this process, known as the Balz-Schiemann process, 4,4 -di-fluorobenzophenone (BDF. 6) has been prepared by this route as a monomer for the production of the engineering plastic poly(ether ether ketone) , or PEEK , by condensation with 1,4-dihydroxybenzene in the presence of potassium carbonate. BDF 6 is superior to its chlorine analog because in aromatic systems the nucleophilic displacement of fluorine is more facile than that of chlorine, leading to a shorter polymerization time and a better quality product containing less degradation impurities. 

The acid-base Nafion composite membranes include blends of Nafion with polypyrrole (PPy) [98-104], polybenzimidazole (PBI) [105-107], poly (propyleneoxide) (PPO) [108, 109], polyfurfuryl alcohol (PFA) [110], poly(vinyl alcohol) (PVA) [111-115], sulfonated phenol-formaldehyde (sPF) [116], polyvinylidene fluoride (PVdF) [117-122], poly(p-phenylene vinylene) (PPV) [123], poly(vinyl pyrrolidone) (PVP) [124] polyanifine (PANI) [125-128], polyethylene (PE) [129], poly(ethylene-terephtalate) [130], sulfated p-cyclodextrin (sCD) [131], sulfonated poly(ether ether ketone) (sPEEK) [132-135], sulfonated poly(aryl ether ketone) (sPAEK) [136], poly(arylene ether sulfone) (PAES) [137], poly(vinylimidazole) (PVl) [138], poly(vinyl pyridine) (PVPy) [139], poly (tetrafluoroethylene) (PTFE) [140-142], poly(fluorinated ethylene-propylene) [143], sulfonated polyhedral oligomeric silsesquioxane (sPOSS) [144], poly (3,4-ethylenedioxythiophene) (PEDT) [145, 146], polyrotaxanes (PR) [147], purple membrane [148], sulfonated polystyrene (PSSA) [149, 150], polystyrene-b-poly(ethylene-ran-butylene)-bpolystyrene (SEES) [151], poly(2-acrylamido-2-methyl-l-propanesulphonic acid-co-l,6-hexanediol propoxylate diacrylate-co-ethyl methacrylate) (AMPS) [152], and chitosan [31]. A binary PVA/chitosan [153] and a ternary Nafion composite with PVA, polyimide (PI) and 8-trimethoxy silylpropyl glycerin ether-1,3,6-pyrenetrisulfonic acid (TSPS) has also been reported [154]. 

Xie J, Peng WY, Li G, Jiang JM. Synthesis and characterization of poly(aryl ether ketone)s with fluorinated phenyl in the side chain. Polym Bull 201 l 67(l) 45-56. 

Phosphonated polymers with fluorinated backbones have been obtained by reacting fluorinated poly(atylene ether)s with a H-phosphonate diester in the presence of Pd(PPh3)4 (Scheme 13.3d). Using fluorinated aromatic polymers as the backbone can be expected to improve the dimensional stability of the membranes compared to aromatic polymers with hydrocarbon backbones because of the increased hydrophobicity induced by the presence of the fluorocarbon. The phosphonated polymers with fluorinated aromatic backbones reached a conductivity of 6 mS cm at 95% RH at 80 °C and 2.6 mS cm in water at room temperature, which was below that of Nafion 117. 

Banerjee et al. [47] synthesized a diamine monomer, namely, 4,4 -(7w(aminophenoxy)-3,3-trifluoromethyl terphenyl, and furthermore prepared fluorinated polyimides (3-70 to 3-72 in Table 3.4). The Tg of the polyimides depended on the rigidity of the dianhydride unit. The polyimide with PMDA as dianhydride had the highest Tg of 294 °C in the series, with a thermal stability as high as 532 °C in an air atmosphere. The TS of the poly(ether imide) s were in the range 96-112 MPa with an EB in the... 

A new aromatic diamine monomer with four pendant -CF3 groups was successfully synthesized by a three-step reaction using w(4-fluorophenyl)sulfone and A-bromosuccinimide as starting materials. Then, a series of fluorinated poly(ether sulfone imide)s was conveniently prepared from the diamine and three aromatic dianhydrides (BPDA, BTDA, and ODPA) via one-step solution polycondensation. 

Y. Liu, Y. Zhang, S. Guan, L. Li, Z. Jiang, Synthesis and properties of soluble fluorinated poly(ether imide)s with different pendant groups. Polymer 49 (25) (2008) 5439-5445. 

C. Wang, W. Chen, Y. Chen, X. Zhao, J. Li, Q. Ren, New fluorinated poly(ether sulfone imide) s with high thermal stability and low dielectric constant, Mater. Chem. Phys. 143 (2) (2014) 773-778. 

E.A. Mistri, A.K. Mohanty, S. Banerjee, Synthesis and characterization of new fluorinated poly(ether imide) copolymers with controlled degree of sulfonation for proton exchange membranes, J. Membr. Sci. 411 (2012) 117-129. 

---