Oligomers, aryl-ether

Decafluorobiphenyl [434-90-2] C F C F (mol wt, 334.1 mp, 68°C bp, 206°C), can be prepared by I Jllmann coupling of bromo- [344-04-7] chloro- [344-07-0] or iodopentafluorobenzene [827-15-6] with copper. This product shows good thermal stabiHty decafluorobiphenyl was recovered unchanged after 1 h below 575°C (270). Decafluorobiphenyl-based derivatives exhibit greater oxidative stabiHty than similar hydrocarbon compounds (271). Therm ally stable poly(fluorinated aryl ether) oligomers prepared from decafluorobiphenyl and bisphenols show low dielectric constant and moisture absorption which are attractive for electronic appHcations (272). 

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. 

Table 1. Characteristics of amine terminated aryl ether oligomers ...

The synthesis of the bis(amino) aryl ether ketimine oligomer was carried out in an analogous fashion to the poly(aryl ether) oligomers described before (Scheme 5) [43]. The ketimine functional 4,4 -bisfluoride was reacted with hyd-roquinone and 3-aminophenol in an NMP/toluene solvent mixture in the presence of potassium carbonate. The characteristics of the oHgomer synthesized are shown in Table 1 (sample le). 

Table 2 contains the characteristics of the amic ester-aryl ether copolymers including coblock type, composition, and intrinsic viscosity. Three series of copolymers were prepared in which the aryl ether phenylquinoxaline [44], aryl ether benzoxazole [47], or aryl ether ether ketone oligomers [57-59] were co-re-acted with various compositions of ODA and PMDA diethyl ester diacyl chloride samples (2a-k). The aryl ether compositions varied from approximately 20 to 50 wt% (denoted 2a-d) so as to vary the structure of the microphase-separated morphology of the copolymer. The composition of aryl ether coblock in the copolymers, as determined by NMR, was similar to that calculated from the charge of the aryl ether coblock (Table 2). The viscosity measurements, also shown in Table 2, were high and comparable to that of a high molecular weight poly(amic ethyl ester) homopolymer. In some cases, a chloroform solvent rinse was required to remove aryl ether homopolymer contamination. It should also be pointed out that both the powder and solution forms of the poly(amic ethyl ester) copolymers are stable and do not undergo transamidization reactions or viscosity loss with time, unlike their poly(amic acid) analogs.

Macrocyclic aryl ether ketone oligomers containing the 1,2-dibenzoyl-... 

A convenient and efficient synthetic route to a new class of macrocyclic aryl ether ether sulfide oligomers was reported. The process is shown in Fig. 28. This new class of cyclic oligomers is prepared in excellent yield by quantitative chemical reduction of macrocyclic aryl ether ether sulfoxide oligomers with oxalyl chloride and tetrabutylammonium iodide. The cyclic sulfoxide oligomeric precursors are prepared in high yields by an aromatic nucleophilic substitution reaction from bis(4-fluorophenyl) sulfoxide with potassium salts of bisphenols under high-dilution conditions [99]. 

Fig. 28 Synthesis of macrocyclic aryl ether ether sulfide oligomers...

We recently have reported our initial studies on step-growth block copolymers containing segments of poly (aryl ethers) and poly (aryl carbonates) (9,10). The multiblock [ A-B ]n block copolymers were prepared by phosgenation in methylene chloride/pyridine solution either by what was termed an in situ or by a coupled oligomer technique (JO). The choice of polycarbonates and poly (aryl ethers) for initial studies was based on the several considerations. Copolymerization is feasible since the end groups in the two oligomers can be identical, as shown in Structures 1 and 2. Considerable information is available in the... 

A highly porous polymeric foam can be prepared through emulsion templating by polymerizing the continuous phase of high internal phase emulsions [150], A maleimide-terminated aryl ether sulfone oligomer was copolymerized with divinylbenzene in the continuous phase, using a mixed surfactants system, cetyltrimethylammonium bromide, dodecylbenzene-sulfonic acid sodium salt, and a peroxide initiator. The polymers show a CO2 adsorption and improved mechanical properties. The materials exhibit an open cell and a secondary pore structure with surface areas of a 400 m g ... 

Mullins MJ, Woo EP, Balon KE, Murray DJ, Chen CCC. Cyclic poly(aryl ether) oligomers. US patent 5264538, assigned to The Dow Chemical Company, Midland, MI 1993. 

Anionic and Cationic Polymerizations o Radical Polymerization Advances o Coordination Polymerizations 0 Step-Growth Polymerization Advances 0 Synthesis of Tactic Polymers o Stereoblock Copolymers o Dispersion Polymerizations o Cellulosic Graft Copolymers o Diels-Alder Polymer Forming Reactions o A New Path To Phenolic Resins o Nitrogen Heterocycle Polymerizations o Optically Active Polymers o Poly (Phenylene Sulfide) o Poly (Aryl Ethers) o (Poly (Aryl Ether Sulfones) o Epoxy and Isocyanate Resin Replacement o Azlactone Functionalized Oligomers o Epoxy Resin-Isocyanate Reactions o Chelating Polymers o Oxazoline Functionalized Polymers o Poly (Alkyl Methacrylates) o Macromers... 

SYNTHESIS AND PROPERTIES OF ACETYLENE TERMINATED ARYL-ETHER OLIGOMERS... 

More recent studies have been concerned with the utilization of acetylene functionality and designing a system which would have all the processing criteria of an epoxide system. Materials which process analogously to the state-of-the-art epoxides require a very flexible backbone which will exhibit a low Tg before cure. The study provided a flexible aryl-ether system which Incorporates a phenylsul-fone backbone and has been referred to as ATS. The initial synthesis of ATS Involved the nucleophilic displacement reaction of various leaving groups in the 4,4 positions of diphenylsulfone with the metallic salt of m-hydroxyphenylacetylene. Research in our laboratory for lower cost precursors to ATS has led to the synthesis of bromo end-capped phenylsulfone oligomers via the Ullmann ether synthesis. 

The general procedure for separation of monomer from oligomer was column chromatography. Separations were normally carried out after the Ullmann reaction, at the dibromo stage of the reaction sequence. The dibromo aryl-ethers were then converted as monomer or as a combination of monomer and oligomer to the acetylenes. The following are representative of the procedures used ... 

The synthesis of the oligomers was carried out by the reaction of various aromatic bis-diols with m-dibromobenzene leading to a series of bromo end-capped, aryl-ether systems. Pyridine was used as the solvent for the reactions, and anhydrous potassium carbonate was utilized to generate the metallic salts of the bis-diols.. In an effort to promote low molecular weight oligomers, the molar ratio of m- dibromobenzene to aromatic bls-diol used in the S3mthesls... 

A series of acetylene-terminated, aryl-ether thermoset systems were prepared by an Ullmann ether synthesis involving the condensation of various salts of aromatic bis—diols with m—dibromobenzene. The bromo end-capped oligomers were converted to the acetylene-terminated systems by the catalytically-induced, bromo-displacement reaction with 2-methyl-3-but3m-2-ol, followed by base hydrolysis. 

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