Poly ether precursor

PEEK precursors, 342 PEEKEK. See Poly(arylene ether ether ketone ether ketone) (PEEKEK) PEEKK. See Poly(ether ether ketone ketone) (PEEKK)... 

A potentially valuable characteristic of poly(ether-ketone-carborane)s is that they display enormously enhanced char-yields (up to 95% on pyrolysis in air), compared to the yields obtained from analogous all-aromatic polymers.7 This behaviour suggests that carborane-based polyketones such as 7 could eventually find application as fire-retardants and as precursor polymers for carbon-ceramic materials. 

Poly[ i]catenanes having the structure depicted in Fig. If are significantly more easily prepared than [njpolycatenanes relatively few examples are nevertheless known. Illustrated in Fig. 8 is the formation of a poly-[2]catenane from a precursor 25 containing two covalently linked ringed poly ethers. When treated with the... 

The highly intractable chemical stmcture vMch. inq)arts the outstanding mechanical properties also makes the PATs very difficult to process (4, 5). In the ftilly imidized form PAI is not processable hence a poly(amic acid) (PAA) precursor is the usual form in which they are supplied and bricated. The precursors themselves have very hi viscosities in the melt state and hence the flow characteristics tend to be very poor. Semicrystalline and amorphous polyamides (6) and aromatic sulfone polymers such as poly(phenylene sulfide), poly(ether sulfone) and polysulfone (7) have been blended with the precursor to PAI, to obtain better flow characteristics. 

In an application-oriented feasibility study [46], precursors of polymer microfibrillar-rein-forced composites (MFC) containing poly(ether)-WocA -amide (PEBA) and poly(etliylene terephthalate) (PET) with varying cold-draw ratio are studied. The studied strands are relatively thick, because presently the achievable microbeam at HASYLAB in Hamburg is relatively wide. The results from a direct analysis of the smeared measured patterns are compared to results obtained after tomographic reconstruction. Ideas for advanced practical applications reflect of the XSF-CT method are discussed. 

Finally, syntheses of poly(arylene ether)s by modification of precursors should be mentioned. All the syntheses described in [271-273] were based on poly(ether ketone)s derived from phthaloyl bisfluorobenzene (172). The tertiary amine catalyzed condensation with benzylamine yielded the poly(isoquinoline ether)s (171), whereas condensation with hydrazine produced the polyphthalazines (173). High glass transitions and high thermostabilities are characteristic for all these poly(arylene ether)s. 

Poly(ether sulfide)s were also prepared by a precursor route, 4,4 -Difluorodiphe-nylsulfoxide (234) was used as electrophilic monomer in combination with hydroquinone or 4,4 -dihydroxybiphenyl. The resulting poly(ether sulfoxide)s were then reduced in tetrachloroethane by means of oxalylchloride and tetrabutylammonium fluoride (235) [357]. Furthermore, the preparation of sulfonated poly(phenylene-sulfide) should be mentioned. SO3 served as sulfonating agent and the sulfonated polysulfide was treated with SOCI2, whereby a poly sulfide with SO2CI and Cl substituents was obtained [358]. 

Carr, R.H. Jackson, A.T. Preliminary Matrix-Assisted Laser Desorption Ionization Time-of-Flight and Field Desorption Mass Spectrometric Analyses of Polymeric Methylene Diphenylene Diisocyanate, Its Amine Precursor and a Model Poly ether Prepolymer. Rapid Commun. Mass Spectrom. 1998, 12, 2047-2050. 

These synthetic difficulties can be overcome by the use of a soluble precursor for the target polymer. Thus, conductive polymers such as poly(p-phenylenevinylene)(22-25) and poly(p-phenylene)(26-28) which are insoluble in common solvents, arc synthesized via soluble precursors. Thermostable plastics such as poly(ether ether ketone) (PEEK)( 29) and poly(arylene sulride ketone)(iO) are also obtained via soluble precursors. 

As with poly(phosphazene) precursors, thermolysis of 2 was carried out in evacuated, sealed, heavy-walled glass ampules or in stainless steel Parr reactors. All the N-silylsulfonimidates that were examined, condensed betwen 120 and 170 C, usually to produce a two-phase mixture of solid polymer and liquid silyl ether and any uncondensed precursor (16J8) (equation 6). The extent of condensation was determined primarily by NMR spectroscopy of the liquid content and also by weighing the volatile silyl ether where possible (usually for Me3SiOCH2CF3). 

Diphenol/thiophenol is one of the most important polymer precursors for synthesis of poly(aryl ethers) or poly-(aryl sulfides) in displacement polymerizations. Commonly used bisphenols are 4,4 -isopropylidene diphenol or bisphenol-A (BPA) due to their low price and easy availability. Other commercial bisphenols have also been reported [7,24,25]. Recently, synthesis of poly(aryl ethers) by the reaction of new bisphenol monomers with activated aromatic dihalides has been reported. The structures of the polymer precursors are described in Table 2. Poly(aryl ether phenylquinoxalines) have been synthesized by Connell et al. [26], by the reaction of bisphenols containing a preformed quinoxaline ring with... 

There have been a number of different synthetic approaches to substituted PTV derivatives proposed in the last decade. Almost all focus on the aromatic ring as the site for substitution. Some effort has been made to apply the traditional base-catalyzed dehydrohalogenation route to PTV and its substituted analogs. The methodology, however, is not as successful for PTV as it is for PPV and its derivatives because of the great tendency for the poly(u-chloro thiophene) precursor spontaneously to eliminate at room temperature. Swager and co-workers attempted this route to synthesize a PTV derivative substituted with a crown ether with potential applications as a sensory material (Scheme 1-26) [123]. The synthesis employs a Fager condensation [124] in its initial step to yield diol 78. Treatment with a ditosylate yields a crown ether-functionalized thiophene diester 79. This may be elaborated to dichloride 81, but pure material could not be isolated and the dichloride monomer had to be polymerized in situ. The polymer isolated... 

Hedrick et al. reported imide aryl ether ketone segmented block copolymers.228 The block copolymers were prepared via a two-step process. Both a bisphenol-A-based amorphous block and a semicrystalline block were prepared from a soluble and amorphous ketimine precursor. The blocks of poly(arylene ether ether ketone) oligomers with Mn range of 6000-12,000 g/mol were coreacted with 4,4,-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) diethyl ester diacyl chloride in NMP in the presence of A - me thy 1 morphi 1 i nc. Clear films with high moduli by solution casting and followed by curing were obtained. Multiphase morphologies were observed in both cases. 

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