Synthesis and polymerization reactions of cyclic imino ethers. VI. Polymers with biphenyl structure

A monomer of the AB‐type and a bifunctional comonomer of the AA‐type containing two 2‐oxazoline rings and a biphenyl structural unit were prepared from the corresponding carboxylic acids via their esterification and subsequent amidation with an aminoalcohol. The cyclization of an amide to 2‐oxazoline structure was achieved by treatment with thionyl chloride followed by liberation of the free base with sodium hydrocarbonate in an aqueous solution. The prepared monomers were used for the polyaddition polymerization of the AB‐type monomer having a 2‐oxazoline and phenol group bound on adjacent rings of the biphenyl structure in solution. The monomer of the AA‐type was used for AA+BB‐type polyaddition reactions with aliphatic dicarboxylic acids. Both types of polymerizations have been performed in melt and in solution. The structures of the polymers were determined, and the thermal properties of the polymers were evaluated. Liquid‐crystalline (LC) structures of the prepared polymers were observed by DSC measurements and optical microscopy. The polyaddition reactions of the monomers containing a 2‐oxazoline ring and a biphenyl unit represent a new efficient way for the preparation of a biphenyl unit containing poly(ether amide)s and poly(ester amide)s. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and polymerization reactions of cyclic imino ethers. I. Ring‐opening homopolyaddition of AB‐type hydroxyphenyl‐substituted 2‐oxazolines

Homopolyaddition reactions of AB‐type monomers containing a 2‐oxazoline and a phenol group in different positions of the phenyl ring, namely, 2‐(4‐hydroxyphenyl)‐2‐oxazoline, 2‐(3‐hydroxyphenyl)‐2‐oxazoline, 2‐(2‐hydroxyphenyl)‐2‐oxazoline, and 2‐(4‐hydroxyphenyl)‐4,4‐dimethyl‐2‐oxazoline, were studied. Except for 2‐(4‐hydroxyphenyl)‐4,4‐dimethyl‐2‐oxazoline, the reaction carried out in bulk or a solution of highly boiling solvents resulted in the formation of poly(ether amide)s with molecular weights in the range of 10³ to 10⁴ as measured by vapor pressure osmometry and gel permeation chromatography. A mechanism of the growth reaction, including a nucleophilic attack of a phenol group to a 2‐oxazoline ring in the 5‐position, was suggested. The polymerization was accompanied by a side reaction of the amido groups formed by the primary reaction of the 2‐oxazoline ring. This led to branching of the main chain. The thermal properties of the prepared polymers were evaluated. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 343–355, 2006     

Synthesis and properties of fluorine‐containing poly(aryl ether oxadiazole)s

Fluorine‐containing poly(aryl ether 1,3,4‐ozadiazole)s were synthesized by the nucleophilic aromatic substitution reaction of 2,5‐bis(2,3,4,5,6‐pentafluorophenyl)‐1,3,4‐oxadiazole and various bisphenols in the presence of potassium carbonate. The polymerizations were carried out at 30 °C in 1‐methyl‐2‐pyrrolidinone to avoid the gelation caused by a crosslinking reaction at para and ortho carbons to the 1,3,4‐oxidiazole ring. The obtained polymers were all para‐connected linear structures. The obtained fluorine‐containing poly(aryl ether 1,3,4‐ozadiazole)s showed excellent solubility and afforded tough, transparent films by the solution‐casting method. They also exhibited a high glass transition temperature depending on the molecular structure, and the glass transition temperature could be controlled by the bisphenols in the range of 157–257 °C. They showed good thermal stability and excellent hydrophobicity due to the incorporation of the 2,3,5,6‐tetrafluoro‐1,4‐phenylene moiety. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2855–2866, 2007     

Synthesis of fluorine‐containing star‐shaped poly(vinyl ether)s via arm‐linking reactions in living cationic polymerization

Various types of fluorine‐containing star‐shaped poly(vinyl ether)s were successfully synthesized by crosslinking reactions of living polymers based on living cationic polymerization. Star polymers with fluorinated arm chains were prepared by the reaction between a divinyl ether and living poly(vinyl ether)s with fluorine groups (C₄F₉, C₆F₁₃, and C₈F₁₇) at the side chain using cationogen/Et_1.5AlCl_1.5 in a fluorinated solvent (dichloropentafluoropropanes), giving star‐shaped fluorinated polymers in high yields with a relatively narrow molecular weight distribution. The concentration of living polymers for the crosslinking reaction and the molar feed ratio of a bifunctional vinyl ether to living polymers affected the yield and molecular weight of the star polymers. Star polymers with block arms were prepared by a linking reaction of living block copolymers of a fluorinated segment and a nonfluorinated segment. Heteroarm star‐shaped polymers containing two‐ or three‐arm species were synthesized using a mixture of different living polymer species for the reaction with a bifunctional vinyl ether. The obtained polymers underwent temperature‐induced solubility transitions in various organic solvents, and their concentrated solutions underwent sol–gel transitions, based on the solubility transition of a thermoresponsive fluorinated segment. Furthermore, a slight amount of fluorine groups were shown to be effective for physical gelation when those were located at the arm ends of a star polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and evaluation of properties of novel poly(benzimidazole‐amide)s

Novel aromatic polyamides have been prepared by a combination of diacids containing preformed benzimidazole rings and aromatic diamines. By the phosphorylation method of polycondensation, polymers of high molecular weight (inherent viscosities between 0.81 and 2.13 dL/g) were obtained, which showed good solubility in polar aprotic solvents. The combination of aromatic amide linkages and benzimidazole rings along the polymer chain endowed the polymers with high thermal resistance and excellent mechanical properties. Glass transition temperatures fell in the range of 290–330 °C as measured by differential scanning calorimetry, and initial decomposition temperatures under nitrogen were over 480 °C as measured by thermogravimetric analysis. Some polymer films showed outstanding tensile strength (over 150 MPa) and moduli (up to 5 GPa). The presence of benzimidazole rings in the current polyamides greatly enhanced their hydrophilicity in comparison with classical wholly aromatic polyamides; thus, although aromatic polyamide films normally show water sorption values of only 4–8%, some of the current poly(benzimidazole amide)s show water sorption up to 19% in a 65% relative humidity atmosphere. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7566–7577, 2008     

A new category of thermally stable poly(ether amide ether imide)s with increased solubility

Two new poly(ether amide ether imide)s (PEAEIs) were prepared from a new diamine (DA) containing ether, aliphatic, amide, naphthyl and pyridine functional groups that resulted flexible and thermally stable ultimate polymers. The DA was synthesized via two steps, starting from nucleophilic substitution reaction of 1,8‐diamino‐3,6‐dioxaoctane with 6‐chloronicotinoyl chloride in the presence of propylene oxide which, afforded dichloro‐diamide (DCDA) compound. In the second step for the preparation of DA, reaction of DCDA compound with 5‐amino‐1‐naphthol in the presence of K₂CO₃ was achieved. The new DA was then polycondensed with 2,2'‐bis‐(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride and pyromellitic dianhydride to produce PEAEIs. The precursor, monomer and obtained polymers were entirely characterized by FT‐IR and ¹H‐NMR spectroscopy and elemental analysis techniques. The physical properties of the polymers including solubility, thermal behavior, thermal stability, inherent viscosity, morphology and mechanical properties were studied. The new PEAEIs exhibited favorable balance of physical and thermal properties, and their solubility was improved without sacrificing their thermal stability. Copyright © 2013 John Wiley & Sons, Ltd.     

Studies on calcium‐containing poly(urethane ether)s

The calcium salt of mono(hydroxyethoxyethyl)phthalate [Ca(HEEP)₂] was synthesized by the reaction of diethylene glycol, phthalic anhydride, and calcium acetate. Calcium‐containing poly(urethane ether)s (PUEs) were synthesized by the reaction of hexamethylene diisocyanate (HMDI) or tolylene 2,4‐diisocyanate (TDI) with a mixture of Ca(HEEP)₂ and poly(ethylene glycol) (PEG₃₀₀ or PEG₄₀₀) with di‐n‐butyltin dilaurate as a catalyst. A series of calcium‐containing PUEs of different compositions were synthesized with Ca(HEEP)₂/PEG₃₀₀ (or PEG₄₀₀)/diisocyanate (HMDI or TDI) molar ratios of 2:2:4, 3:1:4, and 1:3:4 so that the coating properties of the PUEs could be studied. Blank PUEs without calcium‐containing ionic diols were also prepared by the reaction of PEG₃₀₀ or PEG₄₀₀ with HMDI or TDI. The PUEs were well characterized by Fourier transform infrared, ¹H and ¹³C NMR, solid‐state cross‐polarity/magic‐angle‐spinning ¹³C NMR, viscosity, solubility, and X‐ray diffraction studies. The thermal properties of the polymers were also studied with thermogravimetric analysis and differential scanning calorimetry. The PUEs were applied as top coats on acrylic‐coated leather, and their physicomechanical properties were also studied. The coating properties of PUEs, such as the tensile strength, elongation at break, tear strength, water vapor permeability, flexing endurance, cold crack resistance, abrasion resistance, color fastness, and adhesive strength, were better than the standard values. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2865–2878, 2003     

Synthesis of backbone thermo and pH dual‐responsive hyperbranched poly(amine‐ether)s through proton‐transfer polymerization

Stimuli‐responsive hyperbranched polymers have attracted great attention in recent years because of their wide applications in biomedicine. Through proton‐transfer polymerization of triethanolamine and 1,2,7,8‐diepoxyoctane with the help of potassium hydride, a series of novel backbone thermo and pH dual‐responsive hyperbranched poly(amine‐ether)s were prepared successfully in one‐pot. The degrees of branching of the resulting polymers were at 0.40–0.49. Turbidity measurements revealed that hyperbranched poly(amine‐ether)s exhibited thermo and pH dual‐responsive properties in water. Importantly, these responsivities could be readily adjusted by changing the polymer composition as well as the polymer concentration in aqueous solution. Moreover, in vitro evaluation demonstrated that hyperbranched poly(amine‐ether)s showed low cytotoxicity and efficient cell internalization against NIH 3T3 cell lines. These results suggest that these backbone thermo and pH dual‐responsive hyperbranched poly(amine‐ether)s are promising materials for biomedicine. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Poly(cyclic imino ether)s Beyond 2‐Substituted‐2‐oxazolines

2‐Oxazolines (2‐OZO) are 5‐membered cyclic imino ethers whose cationic ring‐opening polymerization (CROP) mechanism and resulting polymer properties are extensively studied. However, also 6‐ and 7‐membered cyclic imino ethers can be polymerized via CROP. Together with the much less studied 4‐ and 5‐substituted main‐chain chiral poly(2‐oxazoline)s (P‐2‐OZO), these compounds are interesting monomers to enhance the versatility of (co)poly(cyclic imino ether)s. To emphasize the potential of such alternative cyclic imino ether monomers, we provide an overview on the polymerizations of 2‐oxazine (2‐OZI) and chiral 4‐ and 5‐substituted 2‐OZO as well as of selected properties of the resulting polymers. In addition, the hydrolysis of these polymers into the corresponding poly(alkylene imine)s will be addressed.

     

Thiol‐epoxy polymerization via an AB monomer: Synthetic access to high molecular weight poly(β‐hydroxythio‐ether)s

A synthetic route is developed for the preparation of an AB‐type of monomer carrying an epoxy and a thiol group. Base‐catalyzed thiol‐epoxy polymerization of this monomer gave rise to poly(β‐hydroxythio‐ether)s. A systematic variation in the reaction conditions suggested that tetrabutyl ammonium fluoride, lithium hydroxide, and 1,8‐diazabicycloundecene (DBU) were good polymerization catalysts. Triethylamine, in contrast, required higher temperatures and excess amounts to yield polymers. THF and water could be used as polymerization mediums. However, the best results were obtained in bulk conditions. This required the use of a mechanical stirrer due to the high viscosity of the polymerization mixture. The polymers obtained from the AB monomer route exhibited significantly higher molecular weights (M_w = 47,700, M_n = 23,200 g/mol) than the materials prepared from an AA/BB type of the monomer system (M_w = 10,000, M_n = 5400 g/mol). The prepared reactive polymers could be transformed into a fluorescent or a cationic structure through postpolymerization modification of the reactive hydroxyl sites present along the polymer backbone. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2040–2046     

Synthesis and photoluminescent and electrochromic properties of aromatic poly(amine amide)s bearing pendent N‐carbazolylphenyl moieties

A series of novel poly(amine amide)s ( IIa – IIl ) with pendent N‐carbazolylphenyl units having inherent viscosities of 0.25–1.06 dL/g were prepared via direct phosphorylation polycondensation from various dicarboxylic acids and a carbazole‐based aromatic diamine. Except for poly(amine amide) IIc , derived from trans‐1,4‐cyclohexanedicarboxylic acid, all the other amorphous poly(amine amide)s were readily soluble in many polar solvents, such as N,N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone (NMP), and could be cast into transparent and flexible films. The aromatic poly (amine amide)s had useful levels of thermal stability associated with relatively high glass‐transition temperatures (268–331 °C), 10% weight loss temperatures in excess of 540 °C, and char yields at 800 °C in nitrogen higher than 60%. These polymers exhibited maximum ultraviolet–visible absorption at 293–361 nm in NMP solutions. Their photoluminescence in NMP solutions exhibited fluorescence emission maxima around 362 and 448–499 nm for aromatic–aliphatic poly(amine amide)s IIa – IIc and aromatic poly (amine amide)s IId – IIl , respectively. The fluorescence quantum yield in NMP solutions ranged from 0.34% for IIj to 4.44% for IIa . The hole‐transporting and electrochromic properties were examined with electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the poly(amine amide) films cast onto an indium tin oxide coated glass substrate exhibited reversible oxidation at 0.81 V and irreversible oxidation redox couples at 1.20 V versus Ag/AgCl in acetonitrile solutions, and they revealed excellent stability of the electrochromic characteristics, with a color change from yellow to green at applied potentials ranging from 0.00 to 1.05 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4108–4121, 2006     

Linear poly(amide triazole)s derived from d‐glucose

The click reaction between azides and alkynes is been increasingly employed in the preparation of polymers. In this article, we describe the synthesis and click polyaddition reaction of a new A‐B‐type amide monomer—prepared from d ‐glucose as renewable resource—containing the alkyne and azide functions. Both Cu(I)‐catalyzed and metal‐free click polymerization methods were used to prepare glucose‐derived poly(amide triazole)s. The resulting polymers had weight‐average molecular weights in the 45,000–129,000 range and were characterized by GPC, IR, and NMR spectroscopies. Thermal and X‐ray diffraction studies revealed them to be amorphous. Their qualitative solubilities in various solvents and their water sorption have been studied. The poly(amide triazole)s having the alcohol functions protected as methyl ether were water‐soluble. The presence of the amide functions along the polymer chain made these polytriazoles degradable in the presence of sodium deuteroxide. The degradation was monitored by NMR analysis, and the degradation product was characterized by HRMS. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 629–638     

Synthesis and properties of novel poly(aryl ether ketone)s containing both 2,6‐naphthylene moieties and amide linkages in the main chains

A new monomer, 2,6‐bis(4‐phenoxybenzoyl)naphthalene (BPOBON), was easily synthesized via simple synthetic procedures from readily available materials. A series of novel poly(aryl ether ketone)s containing both 2,6‐naphthylene moieties and amide linkages in the main chains were prepared by the Friedel‐Crafts acylation solution copolycondensation of isophthaloyl chloride with a mixture of BPOBON and N,N'‐bis(4‐phenoxybenzoyl)‐1,4‐phenylenediamine (BPBPPD), over a wide range of BPOBON/BPBPPD molar ratios, in the presence of anhydrous AlCl₃ and N‐methylpyrrolidone in 1,2‐dichloroethane. All the polymers are semicrystalline and had remarkably increased T_gs over the conventional PEEK and PEKK due to the incorporation of naphthalene and amide linkages in the main chains. The polymers with 50–70 mol% BPOBON had not only high T_gs of 179–186 °C, but also moderate T_ms of 321–328 °C, which are very suitable for the melt processing. These polymers had tensile strengths of 101.5–107.1 MPa, Young's moduli of 2.13–2.39 GPa, and elongations at break of 11.8–13.7% and exhibited excellent thermal stability and good resistance to organic solvents. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis and properties of poly(carbonate‐co‐ester)s obtained by cationic ring‐opening copolymerization of spiroorthocarbonate and ε‐caprolactone

Cationic ring‐opening copolymerization behavior of 1,5,7,11‐tetraoxaspiro[5.5]undecane (SOC1) and ε‐caprolactone (CL), and the thermal behavior of the obtained copolymers are described. When SOC1 and CL were cationically copolymerized under various feed ratios using BF₃OEt₂ as the initiator in CH₂Cl₂ at 25 °C, the corresponding copolymers were obtained in 77–99% yields. The ¹H NMR spectroscopic analysis of the copolymers revealed that the copolymer compositions were almost identical to the feed ratios, and the diad ratios of SOC1–SOC1/SOC1–CL and CL–SOC1/CL–CL are 48.0/52.0 and 54.3/45.7. These observations proved the random structures of the copolymers without containing the long blocks of the homopolymer sequences. Differential scanning calorimetric (DSC) analysis revealed that the melting points and melting entharpies decreased with the increase of the SOC1 unit compositions, suggesting that the copolymers gain flexibility as the SOC1 unit increases. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2937–2942, 2006     

Synthesis and characterization of highly fluorinated poly(phthalazinone ether)s based on AB‐type monomers

Four different fluorinated methyl‐ and phenyl‐substituted 4‐(4‐hydroxyphenyl)‐2‐(pentafluorophenyl)‐phthalazin‐1(2H)‐ones, AB‐type phthalazinone monomers, have been successfully synthesized by nucleophilic addition–elimination reactions of methyl‐ and phenyl‐substituted 2‐((4‐hydroxy)benzoyl)benzoic acid with 1‐(pentafluorophenyl)hydrazine. Under mild reaction conditions, the AB‐type monomers underwent self‐condensation polymerization reactions successfully and gave fluorinated poly(phthalazinone ether)s with high molecular weights. Detailed structural characterization of the AB‐type monomers and fluorinated polymers was determined by ¹H NMR, ¹⁹F NMR, FTIR, and GPC. The solubility, thermal properties, mechanical properties, water contact angles, and optical absorption of the polymers were evaluated. The polymers had high T_gs varying from 337 to 349 °C and decomposition temperatures (T_{d, 25} wt %) above 409 °C. Tough, flexible films were cast from THF and chloroform solutions. The films showed excellent tensile strengths ranging from 70 to 85 MPa with good hydrophobicities with water contact angles higher than 95.5 °C. The polymers had absorption edges below 340 nm and very low absorbance per cm at higher wavelengths 500–2500 nm. These results indicate that the polymers are promising as high performance materials, for example, membranes and hydrophobic materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1761–1770     

Novel heterocyclic poly(arylene ether ketone)s: Synthesis and polymerization of 4‐(4′‐hydroxyaryl)(2H)phthalazin‐1‐ones with methyl groups

Based on green chemistry, a simple and efficient direct synthesis of 4‐(4′‐hydroxyaryl)(2H)phthalazin‐1‐ones ( 2a–2f ) was developed in a two‐step reaction, in which the Friedel–Crafts acylation reaction of six phenols with phthalic anhydride was initially carried out and then followed by cyclization with hydrazine hydrate in good to excellent yields with high regioselectivity. A number of novel heterocyclic poly(arylene ether ketone)s were prepared conveniently from several unsymmetrical, twist, and noncoplanar phthalazinone‐containing monomers ( 2a–2f ) and an activated difluoro monomer via a N? C coupling reaction. It was very interesting that the obtained monomers and polymers exhibited diverse properties with the variation of the number and location of the substituted methyl groups. All these polymers had a high molecular weight with M_n and η_inh in the range of 44,960–169,000 Da and 0.38–0.79 dL/g, respectively. Actually, the obtained polymers displayed excellent thermal properties with T_g's ranging from 222 to 248 °C and 5% weight loss temperatures in nitrogen higher than 430 °C. Moreover, these polymers were readily soluble in common organic solvents, such as N‐methyl‐2‐pyrrolidone, chloroform, pyridine, and m‐cresol, and could be cast into flexible and colorless or nearly colorless films by spin‐coating or casting processes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1525–1535, 2007     

Synthesis of sulfur‐containing hyperbranched polymers by the bisthiolation polymerization of diethynyl disulfide derivatives

The reaction of phenyl propynyl ether and diphenyl disulfide in the presence of 1 mol % tetrakis(triphenylphosphine)palladium as a model reaction of the polymerization of bis(4‐prop‐2‐ynyloxyphenyl) disulfide ( 1a ) gave a Z‐substituted dithioalkene. No E‐substituted dithioalkene was formed in this reaction. The palladium‐catalyzed bisthiolation polymerization of a diethynyl disulfide derivative, 1a , in benzene, was carried out to give a hyperbranched polymer ( 5a ) containing a Z‐substituted dithioalkene unit after reaction for 4 h at 70 °C. From the gel permeation chromatography analysis (chloroform, PSt standards), the number‐average and weight‐average molecular weights of 5a were found to be 8,100 and 57,000, respectively. The structure of 5a was confirmed by ¹H and ¹³C NMR spectra. The obtained polymer was soluble in common organic solvents such as benzene, acetone, and CHCl₃. Polymerization for more than 5 h gave insoluble products. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3580–3587, 2007     

Soluble,redox‐active,and blue‐emitting poly(amide‐hydrazide)s and poly(amide‐1,3,4‐oxadiazole)s containing pyrenylamine units

Two new aromatic poly(amide‐hydrazide)s (PAHs)‐bearing electroactive pyrenylamine units in the backbone were prepared from the phosphorylation polycondensation reactions of N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene ( 1 ) with p‐aminobenzoyl hydrazide (p‐ABH) and m‐aminobenzoyl hydrazide (m‐ABH), respectively. The PAHs could be further cyclodehydrated into the corresponding poly(amide‐1,3,4‐oxadiazole)s in the range of 300–400 °C in the solid film state. All the hydrazide and oxadiazole polymers were soluble in many polar organic solvents and could afford flexible and strong films via solution casting. The poly(amide‐1,3,4‐oxdiazole)s had high glass‐transition temperatures (294–309 °C) and high thermal stability (10% weight‐loss temperature in excess of 520 °C). The dilute solutions of all the hydrazide and oxadiazole polymers showed strong fluorescence with emission maxima around 457–459 nm in the blue region. Copolymers obtained from the polycondensation of equimolar mixture of diacid 1 and 4,4′‐oxydibenzoic acid with p‐ABH or m‐ABH exhibited a significantly increased fluorescence quantum efficiency in comparison with the homopolymers. Cyclic voltammetry results indicated that all the hydrazide and oxadiazole polymers exhibited an ambipolar (n‐ and p‐doping processes) and electrochromic behavior. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Fluoride‐terminated hyperbranched poly(arylene ether phosphine oxide)s via nucleophilic aromatic substitution

A series of AB_x‐type triarylphosphine oxide monomers, bis‐(4‐fluorophenyl)‐(4‐hydroxyphenyl)phosphine oxide ( 4a ), bis‐(3,4‐difluorophenyl)‐(4‐hydroxyphenyl)phosphine oxide ( 4b ), and 4‐hydroxyphenyl‐bis‐(3,4,5‐trifluorophenyl)phosphine oxide ( 4c ) were prepared, characterized, and polymerized under nucleophilic aromatic substitution conditions [N‐methylpyrrolidone (NMP), K₂CO₃] to provide the corresponding hyperbranched poly(arylene ether phosphine oxide)s with number‐average molecular weights ranging from 9200 to 14,600 Da. NMR spectroscopic analysis indicated the presence of highly branched products with an approximate degree of branching of 0.57. The polymers were soluble in a variety of typical organic solvents and displayed excellent thermal stability. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1456–1467, 2002