Polyarylether

As a variation on the base-catalyzed nucleopbilic displacement chemistry described, polysulfones and other polyarylethers have been prepared by cuprous chloride-catalyzed polycondensation of aromatic dihydroxy compounds with aromatic dibromo compounds. The advantage of this route is that it does not require that the aromatic dibromo compound be activated by an electron-withdrawing group such as the sulfone group. Details of this polymerization method, known as the Ullmaim synthesis, have been described (8). 

Polyarylether Ketones. The aromatic polyether ketones are tme thermoplastics. Although several are commercially available, two resins in particular, poly ether ether ketone [31694-16-3] (PEEK) from ICI and poly ether ketone ketone (PEKK) from Du Pont, have received most of the attention. PEEK was first synthesized in 1981 (20) and has been well studied it is the subject of numerous papers because of its potential use in high performance aircraft. Tough, semicrystalline PEEK is prepared by the condensation of bis(4-fiuorophenyl) ketone with the potassium salt of bis(4-hydroxyphenyl) ketone in a diaryl sulfone solvent, such as diphenyl sulfone. The choice of solvent is critical other solvents, such as Hquid HE, promote the reaction but lead to premature low molecular-weight crystals, which do not exhibit sufficient toughness (21). 

Fig. 1. Engineering resins cost vs annual volume (11) (HDT, °C) A, polyetheretherketone (288) B, polyamideimide (>270) C, polyarylether sulfone (170- >200) D, polyimide (190) E, amorphous nylons (124) F, poly(phenylene sulfide) (>260) G, polyarylates (170) H, crystalline nylons (90—220) I, polycarbonate (130) J, midrange poly(phenylene oxide) alloy (107—150) K, polyphthalate esters (180—260) and L, acetal resins (110—140).

Although the synthesis of fluorinated polyarylethers by the reaction between decafluorobiphenyl with bisphenols had previously been described by others [18,19], those polymers were not fully characterized and no particular utility was ascribed to them. 

Table 10 Tg and Thermal Stability of Polyarylethers Synthesized by Displacement Reaction...

R. J. Cotter, Engineering Plastics Handbook of Polyarylethers, Gordon and Breach, Basel, Switzerland, (1995). 

On the basis of the above studies reported thus far, we have designed and synthesized a series of novel poly(aryl ether)s containing both hexafluoroisopropylidene and 1,4-naphthalene moieties. We found these new polyarylethers to have good solubility, high Tg s, and excellent thermal stability. We report herein the synthesis and characterization of these poly(aryl ether)s containing fluorinated 1,4-naphthalene moieties. 

Nylon, polyacetal, polycarbonates, poly(2,6-dimethyl)phenylene oxide (PPO), polyimides, polyphenylene sulfide (PPS), polyphenylene sulfones, polyaryl sulfones, polyalkylene phthalates, and polyarylether ketones (PEEK) are stiff high-melting polymers which are classified as engineering plastics. The formulas for the repeating units of some of these engineering plastics are shown in Figure 1.15. 

Industrially this is often called a polyctherether ketone to emphasize the ether character hence the abbreviation PEEK. In actuality it is a polyarylether ketone. 

Stiff polymers, such as polyphenylene, nylon 66, polyphenylene sulfone, and polyarylether ketone (PEEK), have relatively high Tg values because of the presence of phenylene and sulfone or carbonyl stiffening groups in the chain. 

Aromatic polymers such as PS are readily attacked by chlorine bromine, concentrated sulfuric acid, and nitric acid. These reactions do not decrease the degree of polymerization of the polymers. Aromatic polymers with stiffening groups, such as PPO, polyarylsulfone, polyarylether ketone (PEEK), and polyphenylene sulfide (PPS), are more resistant to attack by corrosives than those with flexibilizing groups. 

Polyarylether ketone (PEEK) has the following repeating unit ... 

In earlier investigations by the authors (2,3) solid sulfonic acid resins containing polyarylether and cyano substituents, (II) and (III), respectively, were prepared and used as proton-conductive membranes, electrode electrolytes, electrode paste, and in membrane electrode assemblies. 

Polymer Compatibilization Blends of Polyarylethers with Styrenic Interpolymers... 

NMR Characterization. The structures of the polyarylethers A-K (Table I) were confirmed through their NMR spectra. As an example of the NMR data, observe the spectrum in Figure 1 for sample K, the condensation product of disodium salt of diphenolic acid and 2,6-di-chlorobezonitrile which was subsequently methylated as discussed above. 

More or less similar behavior has been observed (8) in the blends of the copolymer or the terpolymer with the following bis-A polycarbonate, polyvinyl chloride, poly (ethyl methacrylate), and a terpolymer made from methyl methacrylate, N,N -dimethyl acrylamide, and N-phenyl-maleimide. Because of this unique miscibility characteristic of the a-methyl styrene interpolymers, an attempt was made at compati-bilizing polyarylethers with the interpolymers by attaching pendant chemical groups known to exist in systems with which the interpolymers are miscible. 

Table I illustrates the structures of the modified polyarylethers, their glass-transition temperatures, and their reduced specific viscosities (RV) measured in chloroform at 25°C at a concentration of 0.2 g/100 mL.

Table II contains the mechanical properties and the glass-transition temperatures of the styrenic interpolymers, the various polyarylethers, and their 50/50 blends.

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