Low glass transition temperature fluorocarbon ether bibenzoxazole polymers

Fluorocarbon ether bis(o-aminophenol) monomers were prepared by a multistep synthetic route based on the copper-promoted coupling of 4-iodophenyl acetate with 1,8-diiodoperfluoro-3,6-dioxaoctane, 1,11-diiodoperfluoro-3,9-dioxaundecane, 1,14-diiodoperfluoro-5,10-dimethyl-3,-6,9,12-tetraoxatetradecane, and 1,17-diiodoperfluoro-3,6,9,15-tetraoxaheptadecane. Acetic acidpromoted polycyclocondensations of the monomers with long-chain fluorocarbon ether-diimidate esters and -dithioimidate esters led to linear fluorocarbon ether-bibenzoxazole polymers soluble in 1,1,1,3,3,3-hexafluoroisopropanol and 1,1,2-trichloro-1,2,2-trifluoroethane. Polymer structures were verified by elemental and infrared spectral analysis. The polymers were rubbery gums and could be obtained in the inherent viscosity range of 0.20–0.79 dlg^?1. Selection of monomers governed the glass transition temperatures of the resultant polymers. As expected, the polymers exhibited lower glass transition temperatures with increased fluorocarbon ether content, a minimum value of ?58°C being achieved. None of the polymers exhibited crystalline melt temperatures. Based on thermogravimetric analysis data, the thermooxidative stability of the polymers tended to decrease with increased fluorocarbon ether content. Onset of breakdown during thermogravimetric analysis in air occurred in the 350–400°C range. Isothermal aging of the polymers in air indicated good thermooxidative stability at 260°C; only 5% weight loss was recorded after 200 hr.     

Synthesis of novel fluorocarbon ether bibenzoxazole polymers

Novel fluorocarbon bis(o-aminophenol) monomers were synthesized by a multistep route from 1,3-diiodohexafluoropropane and 1,8-diiodohexadecafluorooctane. The acetic acid-promoted polycondensation of these monomers with fluorocarbon ether-diimidate esters led to linear, soluble fluorocarbon ether-bibenzoxazole polymers with inherent viscosities in the range of 0.10–0.94 dl/g^?1. Polymer structures were verified by elemental and infrared (IR) spectral analysis. Many of the polymers exhibited considerable crystallinity in which the crystalline melt temperatures ranged from 53 to 187°C, as determined by differential scanning calorimetry. Some polymers, however, were isolated as completely amorphous, rubbery gums that exhibited glass transition temperatures as low as ?31°C. Good thermooxidative stabilities were exhibited with onset of weight loss of the polymers during thermogravimetric analysis in an air atmosphere occurring in the 375–450°C range.     

New polyphenylquinoxalines linked by m-terphenyl flexibilizing groups

Three new monomers with phenylglyoxyloyl groups fixed on the 4,4′-, 4,6′-, and 4,4″-positions of m-terphenyl were synthesized by different pathways. They were used to prepare a series of polyphenylquinoxalines by solution polycondensation with 3,3′-diaminobenzidine and 3,3′,4,4′-tetraaminodiphenyl ether. These polymers exhibited excellent oxidative and thermal stability as shown by thermogravimetric analysis and isothermal aging in circulating air between 300 and 450°C. Clear yellow films, cast from m-cresol solution, were used to measure their softening temperature by thermomechanical analysis (TMA). Numerical data thus obtained, indicated a thermoplastic behavior in the temperature range 300 ± 15°C. Crosslinking of the linear polymers by isothermal heat exposure under argon between 300 and 500°C was investigated by means of TMA. Molded materials were fabricated under constant pressure (996 psi) at 500–525°C with an Instron testing machine. These polymers were also used for preliminary evaluation as matrices for 181-E glass reinforced composites. Flexural values obtained after isothermal aging in air up to 400°C indicated a potential use varying from 150 hr at 350°C to 24 hr at 400°C.     

Fluorocarbon polymers with alternating oxyalkylene and oxysilylene units

Linear polymers were prepared by the condensation of bis(dimethylamino)dimethylsilane and 1,4-bis(dimethylaminodimethylsily)benzene with fluorocarbon diols. 1,5-Dihydroxy-3-methyl-1,1,5,5-tetrakis(trifluoromethyl)-2-pentene, the cis addition product of hexafluoroacetone and isobutylene, with the silylbenzene monomer gave a polymer that cured at room temperature to a rubber exhibiting a glass transition temperature of 0°C, low swelling in hydrocarbons, and excellent resistance to hydrolytic, oxidative, and thermal degradation, retaining its flexibility after exposure to air for 3 hr at 305°C. The polymers obtained by condensing 1,5-dihydroxy-1,1,5,5-tetrakis(trifluoromethyl)-2-pentene, the trans addition product of hexafluoroacetone and propylene, with the silylbenzene and the silane monomers had glass transition temperatures of ?12 and ?50°C respectively, and greater resistance to swelling in hydrocarbons.     

Synthesis and properties of poly(arylene ether imide ketone)s

Poly(arylene ether ketone)s containing imide units were prepared by the aromatic nucleophilic displacement reaction of the potassium salts of bisphenols with bis(4-fluorobenzoyl)phthalimides in N-methyl-2-pyrrolidone at elevated temperature. The polymers having inherent viscosities of 0.34–0.77 dL/g were obtained in 2 h. The polymers exhibited glass transition temperatures ranging from 216 to 268°C and decomposition temperatures (5% weight loss under air atmosphere) ranging from 450–570°C mainly depending on the bisphenols used in the polymer synthesis. The isothermal TGA measurements (400°C under air or nitrogen atmosphere) revealed that the 4,4'-biphenol- and hydroquinone-based poly(arylene ether ketone imide)s belong to a superior class of heat resistant polymers. The mechanical properties of these polymers are also described. © 1994 John Wiley & Sons, Inc.     

Synthesis,characterization, and comparison of properties of new fluorinated poly(arylene ether)s containing phthalimidine moiety in the main chain

Four new poly(arylene ether)s have been prepared by the reaction of N‐phenyl‐3,3‐bis(4‐hydroxyphenyl)phthalimidine (PA) with four different perfluoroalkylated monomers namely 1,3‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) benzene, 4,4′‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) biphenyl, 2,6‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) pyridine, and 2,5‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) thiophene. The poly(arylene ether)s were characterized by different spectroscopic, thermal, mechanical, and electrical techniques. The poly(arylene ether) containing quadriphenyl unit in the main chain showed very high glass transition temperature of 291°C and outstanding thermal stability upto 556°C for 10% weight loss under a 4:1 nitrogen:oxygen mixture. The polymers were soluble in a wide range of organic solvents. Transparent thin films of these polymers exhibited tensile strengths upto 75 MPa and elongation at break upto 32%. The films of these polymers showed low water absorption of 0.26%. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and Characterization of Poly(Aryl Ether-Bissulfone)s

A series of poly(aryl ether-bissulfone)s were synthesized from bis-phenols, 4,4′-bis(4-chlorophenylsulfonyl)biphenyl, and 4,4′-bis(4-fluorophenylsulfonyl)biphenyl. The bishalide monomers were synthesized by reaction of 4,4′-bis(chlorosulfonyl)biphenyl with a suitable aryl halide. Potassium carbonate mediated reaction in di-methylacetamide gave high molecular weight polymers in excellent yield. The polymers are soluble in dipolar aprotic solvents. Unlike the corresponding monosulfone analogues, the poly(aryl ether-bissulfone)s exhibited poor solubility in chlorinated hydrocarbons. The glass transition temperatures of the polymers are among the highest known for poly(aryl ether)s (241-271 °C). In addition, the polymers exhibit excellent thermal stability and they produce clear, colorless tough films by solution casting or compression molding.     

Synthesis and properties of poly(arylene ether phenyl-s-triazine)s

A series of new poly(arylene ether phenyl-s-triazine)s was prepared by the nucleophilic aromatic substitution polymerization of the potassium salt of bisphenols with 2,4-bis (halophenyl)-6-phenyl-s-triazine in N-methyl-2-pyrrolidone at elevated temperature. The polymers with inherent viscosities exceeding 0.5 were obtained after polymerization for 1 h using 2,4-bis(fluorophenyl)-6-phenyl-s-triazine as a monomer. The glass transition temperatures of the resulting polymers ranged from 200 to 260°C depending on the bisphenol used in the polymer synthesis. The poly(arylene ether phenyl-s-triazine)s demonstrated excellent thermal stabilities in excess of 490°C (5% weight loss in air). The isothermal TGA measurements (400°C under air or nitrogen atmosphere) revealed that the 4,4'-biphenol- and hydroquinone-based poly(arylene ether phenyl-s-triazine)s belong to the most superior class of heat resistant polymers, such as polyimide Kapton?. The mechanical properties of these polymers are also described. © 1994 John Wiley & Sons, Inc.     

Ester phenyl-as-triazine and ester phenylquinoxaline polymers

A series of new high molecular weight soluble ester phenyl-as-triazine and ester phenyl-quinoxaline polymers were prepared by solution cyclopolycondensation of oxalamidrazone or 3,3′-diaminobenzidine, respectively, with various bis(benzilyl)esters. Ester groups are incorporated within the backbone of the polymer chain and also as pendant groups on the heterocyclic ring. By TGA in air, initial weight losses for the all-aromatic polyester phenyl-as-triazines and polyester phenylquinoxalines began at ca. 350 and 400°C, respectively. Films of ester phenyl-as-triazine and ester phenylquinoxaline polymers exhibited good thermo-oxidative stability after aging in circulating air at 232 and 288°C, respectively. Two phenylquinoxaline model compounds were also prepared.     

Synthesis and optical properties of fluorinated poly(arylene ether phosphine oxide)s

Fluorinated dihydroxy phosphine oxide monomers were synthesized via chlorination, Grignard, and demethylation techniques. The prepared monomer was successfully polymerized with each of the three perfluorinated monomers (decafluorobiphenyl, decafluorobenzophenone, and pentafluorophenylsulfide) by nucleophilic aromatic substitution. The average molecular weight ranged between 7800 and 14,900 g/mol. The glass‐transition temperatures of the polymers were registered in the range of 185–235 °C, and all the polymers exhibited high thermal stability up to 326–408 °C. The results of the refractive‐index measurements indicated control of the refractive index between 1.5181 and 1.5536 and an optical loss of 0.53 dB/cm at 1550 nm. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1497–1503, 2003     

含氰基高性能聚芳醚材料的合成与表征

将合成的含氰基的双二氮杂萘酮单体与二氟芳香单体进行亲核取代反应, 制备了三种含氰基的新型聚芳醚, 并用TGA, DSC和GPC等分析手段对其综合性能进行表征. 结果表明, 含氰基聚芳醚具有优异的热稳定性(T5%>492 ℃)、较高的玻璃化转变温度(Tg=262~320 ℃)和良好的溶解性能, 易溶于氯代烷烃(如氯仿)和极性非质子性溶剂(如DMAc, DMF, NMP等).     

Aromatic poly(1,3,4‐oxadiazole)s and poly(amide‐1,3,4‐oxadiazole)s containing ether sulfone linkages

Polyhydrazides and poly(amide‐hydrazide)s were prepared from two ether‐sulfone‐dicarboxylic acids, 4,4′‐[sulfonylbis(1,4‐phenylene)dioxy]dibenzoic acid and 4,4′‐[sulfonylbis(2,6‐dimethyl‐1,4‐phenylene)dioxy]dibenzoic acid, or their diacyl chlorides with terephthalic dihydrazide, isophthalic dihydrazide, and p‐aminobenzhydrazide via a phosphorylation reaction or a low‐temperature solution polycondensation. All the hydrazide polymers were found to be amorphous according to X‐ray diffraction analysis. They were readily soluble in polar organic solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide and could afford colorless, flexible, and tough films with good mechanical strengths via solvent casting. These hydrazide polymers exhibited glass‐transition temperatures of 149–207 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the solid state at elevated temperatures. Although the oxadiazole polymers showed a significantly decreased solubility with respect to their hydrazide prepolymers, some oxadiazole polymers were still organosoluble. The thermally converted oxadiazole polymers had glass‐transition temperatures of 217–255 °C and softening temperatures of 215–268 °C and did not show significant weight loss before 400 °C in nitrogen or air. For a comparative study, related sulfonyl polymers without the ether groups were also synthesized from 4,4′‐sulfonyldibenzoic acid and the hydrazide monomers by the same synthetic routes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2271–2286, 2001     

Polymers with indane units by cationic polymerization

In spite of the difunctionality of the monomers, cationic polymerization of 1,3- and 1,4-diisopropenylbenzene does not lead to branched or cross-linked products. Instead, soluble polymers are obtained, containing the 1,1,3-trimethylindane system as repetitive unit along the backbone. These polymers are interesting materials because of their high glass transition temperature (200°C-250°C) and good thermal stability in air (2% weight loss at 450°C). Although the molar mass of the polyindanes seems to be limited due to a side reaction, it is possible to produce telechelic polyindanes. Substitution of an alkyl side chain onto the isopropenyl groups of 1,4-diisopropenylbenzene leads to monomers which yield substituted polyindanes with glass transition temperatures as low as 26°C. Such polymers still exhibit good thermal stability: at 340°C a weight loss of only 2% occurs. 1,4-Diisopropenylbenzene can even be anionically polymerized to linear polymers. In this case, the resulting polymer possesses isopropenyl phenyl side groups, which can be used as initiators for cationic polymerization of isobutene to obtain grafted copolymers.     

Polycarbazoles via C?N coupling reactions of phthaloyl bis‐9H‐carbazoles with activated difluorides

1,3‐Phthaloyl bis‐9H‐carbazole (MPC) and 1,4‐phthaloyl bis‐9H‐carbazole (PPC) were synthesized by a Friedel‐Crafts reaction of carbazole with terephthaloyl chloride or isophthaloyl chloride. Homopolymers were obtained by a C? N coupling reaction with activated difluorides and copolymers were synthesized with 4,4′‐biphenol as a comonomer by a nucleophilic substitution reaction between these NH‐ and OH‐containing monomers and the activated difluoro monomers. The inherent viscosities of the polymers ranged from 0.35 to 1.03 dL/g. These polymers exhibited glass‐transition temperatures greater than 238 °C with the PPC‐containing homopolymer showing the highest value, 326.4 °C. The thermal stabilities indicated no significant weight loss below 450 °C and the temperatures of 5% weight loss ranged from 514.0 to 546.3 °C. The polymers showed reasonable solubility in organic solvents such as DMAC, DMSO, and NMP. UV absorption and fluorescence emission properties are presented. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4326–4331, 2009     

Polyphenyl-as-triazines from Perfluoroalkyleneamidrazones

Abstract

High molecular weight polyphenyl-as-triazines were prepared at ambient temperature by the cyclopolycondensation of perfluoroglutaramidrazone and perfluoroadipamidrazone with various bis(1,2-dicarbonyl) monomers. The effect which the perfluoroalkylene group had upon certain chemical and physical properties of the polymers was determined. Thermal evaluation involved TGA, DSC, TMA, and isothermal weight loss studies of films at 232 °C in air. The polymers exhibited excellent hydrolytic stability as evidenced by retention of n _inh after boiling in water (24 hr) and 10% sodium hydroxide solution (8 hr). A stable uncyclized intermediate was isolated from the reaction of perfluoroadipamidrazone and benzil which was cyclized to the phenyl-as-triazine model compound [3,3′ -perfluorotetramethylenedi (5,6-diphenyl-as-triazine)].     

Synthesis and Characterization of Novel Poly(Arylene Ether)s from 4,4′‐Thiodiphenol

Four novel perfluoroalkylated poly(arylene ether)s have been synthesized successfully using four perfluoroalkyl‐activated bisfluoro monomers. These polymers are synthesized through nucleophilic displacement of the fluorine atoms on the benzene ring with 4,4′‐thiodiphenol and are named as 1a, 1b, 1c and 1d, respectively. The polymers obtained by displacement of the fluorine atoms exhibit weight‐average molar masses up to 3.9×10⁴ g · mol^?1 in Gel permeation chromatography. These poly(arylene ether)s showed very high thermal stability up to 548°C for 10% weight loss in TGA under nitrogen and high glass transition temperature (T_g) up to 178°C in DSC depending on the repeat unit structures. The glass transition temperatures taken as peak in tan δ in DMA measurements are in good agreement with the DSC T_g values. All the polymers synthesized are soluble in a wide range of organic solvent such as CHCl₃, CHCl₂, THF, NMP, DMF and toluene. Transparent thin films of these polymers cast from THF exhibited tensile strengths up to 72 MPa, modulus up to 1.69 GPa with low elongation at break depending on their exact repeating unit structures. Rheological properties showed ease of processability of these polymers with no change in melt viscosity with temperature.     

Synthesis and Properties of Aromatic Poly(Ether Sulfone)s and Poly(Etherketone)s Containing Naphthalene or Quinoline Units,and Methyl-Substituted Biphenyl-4,4′-Diols

Abstract

A series of poly(ether sulfone)s and poly(ether ketone)s were synthesized from combinations of 1,5- and 2,6-bis(4-fluorosulfonyl)naphthalene, 2,6-bis(4-fluorobenzoyl)naphthalene, and 2,6-bis(4-fluorobenzoyl)quinoline with 3,3′,5,5′-tetramethylbiphenyl-4,4′-diol and 2,2′,3,3′,5,5′-hexamethylbiphenyl-4,4′-diol. The polycondensations proceeded quantitatively in diphenylsulfone in the presence of anhydrous potassium carbonate to afford polymers with inherent viscosities between 0.40 and 1.28 dL/g measured in N-methyl-2-pyrrolidone or concentrated sulfuric acid. The tetramethyl- and hexamethyl-substituted aromatic polyethers exhibited good thermal stability, did not decompose below 330°C in both air and nitrogen atmospheres, and had higher glass transition temperatures than the corresponding unsubstituted polymers. The methylsubstituted poly(ether sulfone)s and poly(ether ketone)s showed good solubility in such common organic solvents as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, tetrahydrofuran, chloroform, and 1,4-dioxane.     

Synthesis,thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

A series of poly(benzylidene‐ether)esters containing a photoreactive benzylidene chromophore in the main chain were synthesized from 2,6‐bis(4‐hydroxy‐3‐methoxybenzylidene)cyclohexanone (BHMBCH) with various aliphatic and aromatic diacid chlorides by an interfacial polycondensation technique. The intrinsic viscosity of the synthesized homo and copolymers determined by Ubbelohde viscometer was found to be 0.12 to 0.17 dL/g. The molecular structure of the monomer and polymers was confirmed by FT‐IR, ¹H NMR, and ¹³C NMR spectral analyses. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the polymers were stable up to 280 °C and start degrading thereafter. Increase in acid methylene spacer length decreased the thermal stability. The self‐extinguishing property of the synthesized polymers was studied by calculating the limiting oxygen index (LOI) value using a Van Krevelen's equation. The influence of the length of methylene spacer on phase transition was investigated using DSC and odd‐even effect has been observed. Hot‐stage optical polarizing microscopic (HOPM) study showed that most of the polymers exhibited birefringence and opalescence properties. The photolysis of liquid crystalline poly(benzylidene‐ether)esters revealed that α,β‐unsaturated ketone moiety in the main chain dimerises through 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Thermally stable polymers from 1,4,5-naphthalene–tricarboxylic acid and aromatic tetramines

New thermally stable polymers that contained benzimidazole and benzimidazobenzoisoquinoline fragments in polymer chains were synthesized by one-stage cyclopolycondensation of aromatic tetramines (3,3′, 4,4′-tetraminodiphenyl ether, 3,3′,4,4′-tetraminodiphenyl methane, 3,3′,4,4′-tetraminodiphenyl sylfone, and 3,3′-diaminobenzidine) with 1,4,5-naphthalene tricarboxylic acid 4:5–anhydride in polyphosphoric acid and with 1,4,5-naphthalene tricarboxylic acid 4:5–anhydride 1-phenyl ester. All polymers obtained were soluble in concentrated sulfuric acid, 85% phosphoric acid, polyphosphoric acid, methane sylfonic acid. Some were soluble in formic acid. Thermogravimetric analyses indicated that these polymers were stable up to 450–500°C in air. The polymers had good hydrolytic stability.     

Synthesis and properties of hyperbranched polyurethanes,hyperbranched polyurethane copolymers with and without ether and ester groups using blocked isocyanate monomers

Starting from 3,5‐diamino benzoic acid, 2‐hydroxy propyl[3,5‐bis{(benzoxycarbonyl)imino}]benzyl ether, an AB₂‐type blocked isocyanate monomer with flexible ether group, and 2‐hydroxy propyl[3,5‐bis{(benzoxycarbonyl)imino}]benzoate, an AB₂‐type blocked isocyanate monomer with ester group, were synthesized for the first time. Using the same starting compound, 3,5‐bis{(benzoxycarbonyl)imino}benzylalcohol, an AB₂‐type blocked isocyanate monomer, was synthesized through a highly efficient short‐cut route. Step‐growth polymerization of these monomers at individually optimized experimental conditions results in the formation of hyperbranched polyurethanes with and without ether and ester groups. Copolymerizations of these monomers with functionally similar AB monomers were also carried out. The molecular weights of the polymers were determined using GPC and the values (M_w) were found to vary from 1.5 × 10⁴ to 1.2 × 10⁶. While hyperbranched polyurethanes having no ether or ester group were found to be thermally stable up to 217 °C, hyperbranched poly(ether–urethane)s and poly(ester–urethane)s were found to be thermally stable up to 245 and 300 °C, respectively. Glass transition temperature (T_g) of polyurethane was reduced significantly when introducing ether groups into the polymer chain, whereas T_g was not observed even up to 250 °C in the case of poly(ester–urethane). Hyperbranched polyurethanes derived from all the three different AB₂ monomers were soluble in highly polar solvents and the copolymers showed improved solubility. Polyethylene glycol monomethyl ether of molecular weight 550 and decanol were used as end‐capping groups, which were seen to affect the thermal, solution, and solubility properties of polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3877–3893, 2007