Synthesis and properties of thio‐containing poly(ether ether ketone)s

A series of thio‐containing poly(ether ether ketone) (PEESK) polymers was synthesized by the introduction of thio groups from 4,4′ thiodiphenol (TDP) into the poly(ether ether ketone) (PEEK) structure via reaction between the phenol and aromatic fluoride groups. The effect of the thio groups on the properties of the PEESK materials was investigated. Differential scanning calorimetry (DSC) analysis and X‐ray diffraction (XRD) patterns show a depression in the crystallinity of the PEESKs with incorporation of the content of thio groups in the backbones. The crystalline structure was identified as an orthorhombic structure with lattice constants of a = 7.52 Å, b = 5.86 Å and c = 10.24 Å for all crystallizable PEESKs. The crystalline structures of the thio‐containing PEEK polymers were the same as that of the neat PEEK, which means the thio‐containing block in the whole thio‐containing PEEK molecule is almost excluded from the crystalline structure and the crystals are completely formed by ‘non‐thio’ blocks only. Due to the glass transition temperature (T_g) and melting temperature (T_m) depression with increase in the TDP content in the reaction system, the processability of the resultant thio‐containing PEEKs could be effectively improved. Copyright © 2004 Society of Chemical Industry     

Synthesis and properties of novel phosphorus‐containing poly(ether ether ketone ketone)s

A novel monomer, bis[4‐(4‐fluorobenzoyl)phenyl]phenylphosphine oxide, was synthesized through the reaction of bis(4‐chloroformylphenyl) phenyl phosphine oxide with fluorobenzene. Three poly(ether ether ketone ketone)s derived from bis[4‐(4‐fluorobenzoyl)phenyl]phenylphosphine oxide and different aromatic bisphenols were prepared by aromatic nucleophilic substitution reactions. The resulting polymers had inherent viscosities in the range of 0.55–0.73 dL/g. The structures of the poly(ether ether ketone ketone)s were characterized with Fourier transform infrared and ¹H‐NMR. Thermal analysis indicated that the glass‐transition temperatures of the poly(ether ether ketone ketone)s were higher than 200°C, and the 5% weight loss temperatures in nitrogen were higher than 463°C. All the polymers showed excellent solubility in polar solvents such as N‐methyl‐2‐pyrrolidone, dimethylformamide, and dimethylacetamide and could also be dissolved in chlorinated methane. The polymers afforded transparent and flexible films by solvent casting. Organic phosphorous moieties also imparted good flame‐retardancy to the polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Copolymerization and blending of poly(phthalazinone ether ketone)s to improve their melt processability

The melt processability of phthalazinone‐containing poly(aryl ether)s (PAEs) was improved through copolymerization and blending. Poly(phthalazinone ether ketone) (PPEK) copolymers containing phthalazinone and bisphenol‐A (BPA) moieties were synthesized through nucleophilic substitution polycondensation. The PPEK copolymers exhibited high glass transition temperatures, excellent thermooxidative properties, good mechanical properties and improved solubility, all of which can be tailored by changing the molar ratio of phthalazinone to bisphenol monomers. The rheological investigation indicated that the incorporation of the flexible BPA moiety into the main chain lowered the melt viscosity of the copolymers. To improve the melt processability further, polymer blends of a PPEK copolymer/polycarbonate (PC) were prepared. The results suggested that blending is an effective approach for improving the melt processability of phthalazinone‐containing PAEs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2575–2580, 2007     

Synthesis and characterization of organo‐soluble poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains

Poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains were synthesized by polycondensation of each of the two bisphenol monomers viz, 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane and 1,1‐bis(4‐hydroxyphenyl)‐3‐pentadecyl cyclohexane with activated aromatic dihalides namely, 4,4′‐difluorobenzophenone, and 1,3‐bis(4‐fluorobenzoyl)benzene in a solvent mixture of N,N‐dimethylacetamide and toluene, in the presence of anhydrous potassium carbonate. Polymers were isolated as white fibrous materials with inherent viscosities and number average molecular weights in the range 0.70–1.27 dL g^?1 and 76,620–1,36,720, respectively. Poly(ether ether ketone)s and poly(ether ether ketone ketone)s were found to be soluble at room temperature in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, and pyridine and could be cast into tough, transparent, and flexible films from their solutions in chloroform. Wide angle X‐ray diffraction patterns exhibited a broad halo at around 2θ = ～ 19° indicating that the polymers containing pentadecyl chains were amorphous in nature. In the small‐angle region, diffuse reflections of a typically layered structures resulting from the packing of pentadecyl side chains were observed. The temperature at 10% weight loss, obtained from TG curves, for poly(ether ether ketone)s and poly(ether ether ketone ketone)s were in the range 416–459°C, indicating their good thermal stability. A substantial drop in glass transition temperatures (68–78°C) was observed for poly(ether ether ketone)s and poly(ether ether ketone ketone)s due to “internal plasticization” effect of flexible pendant pentadecyl chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Poly(ether ether sulfone amide)s as a new category of processable heat-resistant polymers

The aim of study was to prepare novel polyamides with improved solubility and processability without sacrifice of their thermal and mechanical properties. Polyamides containing ether and sulfone units were obtained via condensation of a special diamine with various diacid chlorides. Poly(ether ether sulfone amide)s were obtained in good inherent viscosities ranging from 0.72 to 0.84 dL/g. All the polyamides were amorphous and readily soluble in polar solvents and swelled in CH₂Cl₂ and tetrahydrofuran. Flexible films of polymers were obtained by solution casting. Polyamide films exhibited good mechanical and thermal stability including the temperature for 10% weight loss of 449–476 °C.     

Facile synthesis and properties of semicrystalline copoly(arylene ether ketone) containing hydroquinone and phthalazinone

Two series of novel copoly(arylene ether ketone) were successfully synthesized from hydroquinone or bisphenol A, bis(4‐fluorophenyl)ketone and 4‐(4‐hydroxyphenyl)‐2,3‐phthalazin‐1‐one with anhydrous potassium carbonate as the catalyst. The synthesized polymers exhibited high glass‐transition temperatures together with excellent thermooxidative stability. The chain structure of these polymers was studied by means of ¹³C‐nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), and wide‐angle X‐ray diffraction (WAXD) techniques. The experimental results showed that these “as‐made” copolyaryleneketones containing hydroquinone moieties exhibited a multiblock chain structure with long segments that mainly consisted mainly of hydroquinone and bis(4‐fluorophenyl)ketone at the middle of the molecular chain. These long segments exhibited crystallites in the produced polymers. The synthesized copolyaryleneketone containing 90 mol % hydroquinone possessed a glass‐transition temperature higher than that of commercial PEEK. The synthesized polymers also exhibited either fair processability or solubility. The glass‐transition temperatures, solubility, and tensile strengths of the two series of copolyaryleneketones tended to increase with increasing phthalazinone moiety content. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2687–2695, 2001     

Synthesis and properties of copolymers of poly(ether ketone ketone) and poly(ether amide ether amide ether ketone ketone)

Poly(aryl ether ketone)s (PAEKs) are a class of high‐performance engineering thermoplastics known for their excellent combination of chemical, physical and mechanical properties, and the synthesis of semicrystalline PAEKs with increased glass transition temperatures (T_g) is of much interest. In the work reported, a series of novel copolymers of poly(ether ketone ketone) (PEKK) and poly(ether amide ether amide ether ketone ketone) were synthesized by electrophilic solution polycondensation of terephthaloyl chloride with a mixture of diphenyl ether and N,N′‐bis(4‐phenoxybenzoyl)‐4,4′‐diaminodiphenyl ether (BPBDAE) under mild conditions. The copolymers obtained were characterized using various physicochemical techniques. The copolymers with 10–35 mol% BPBDAE are semicrystalline and have markedly increased T_g over commercially available poly(ether ether ketone) and PEKK due to the incorporation of amide linkages in the main chain. The copolymers with 30–35 mol% BPBDAE not only have high T_g of 178–186 °C, but also moderate melting temperatures of 335–339 °C, having good potential for melt processing. The copolymers with 30–35 mol% BPBDAE have tensile strengths of 102.4–103.8 MPa, Young's moduli of 2.33–2.45 GPa and elongations at break of 11.7–13.2%, and exhibit high thermal stability and good resistance to organic solvents. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of polyetherimides containing multiple ether linkages and pendent pentadecyl chains

4‐(4‐(4‐(4‐Aminophenoxy)‐2‐pentadecylphenoxy)phenoxy)aniline (APPPA) was synthesized starting from cashew nut shell liquid‐derived bisphenol, i.e. 4‐(4‐hydroxyphenoxy)‐3‐pentadecylphenol, by nucleophilic substitution reaction with 4‐chloronitrobenzene followed by reduction of the formed 4‐(4‐nitrophenoxy)‐1‐(4‐(4‐nitrophenoxy)phenoxy)‐2‐pentadecylbenzene. Three new polyetherimides containing multiple ether linkages and pendent pentadecyl chains were synthesized by one‐step high‐temperature solution polycondensation of APPPA in m‐cresol with three aromatic dianhydrides, i.e. 3,3′,4,4′‐oxydiphthalic anhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride. Inherent viscosities and number‐average molecular weights of the polyetherimides were in the ranges 0.66–0.70 dL g^?1 and 17 100–29 700 g mol^?1 (gel permeation chromatography, polystyrene standards), respectively, indicating the formation of reasonably high molecular weight polymers. The polyetherimides were soluble in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, m‐cresol, N,N‐dimethylformamide, N,N‐dimethylacetamide, N‐methylpyrrolidone and dimethylsulfoxide, and could be cast into transparent, flexible and tough films from their solutions in chloroform. The polyetherimides exhibited glass transition temperatures (T_g) in the range 113–131 °C. The lowering of T_g could be attributed to the combined influence of flexibilizing ether linkages and pentadecyl chains which act as ‘packing‐disruptive’ groups. The temperature at 10% weight loss (T₁₀), determined from thermogravimetric analysis in nitrogen atmosphere, was in the range 460–470 °C demonstrating good thermal stability. The virtues of solubility and large gap between T_g and T₁₀ mean that the polyetherimides containing pendent pentadecyl chains have possibilities for both solution as well as melt processability. © 2015 Society of Chemical Industry     

Synthesis and characterization of poly(ether ketone ether ketone ketone)/poly(ether ether ketone ketone) copolymers containing naphthalene and pendant cyano groups

2,6‐Bis(β‐naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of β‐naphthol with 2,6‐difluorobenzonitrile in N‐methyl‐2‐pyrrolidone (NMP) in the presence of KOH and K₂CO₃. Poly(ether ketone ether ketone ketone)(PEKEKK) /poly(ether ether ketone ketone) (PEEKK) copolymers containing naphthalene and pendant cyano groups were obtained by electrophilic Friedel‐Crafts polycondensation of terephthaloyl chloride (TPC) with varying mole proportions of 4,4′‐diphenoxybenzophenone (DPOBP) and 2,6‐bis(β‐naphthoxy)benzonitrile (BNOBN) using 1,2‐dichloroethane (DCE) as solvent and NMP as Lewis base in the presence of anhydrous AlCl₃. The resulting polymers were characterized by various analytical techniques, such as FTIR, DSC, TG, and WAXD. The results indicated that the crystallinity and melting temperature of the polymers decreased with increase in concentration of the BNOBN units in the polymer, the glass transition temperature of the polymers increased with increase in concentration of the BNOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 536°C in N₂ atmosphere. The copolymers have good resistance to acidity, alkali, and organic solvents. Because of the melting temperature (T_m) depression with increase in the BNOBN content in the reaction system, the processability of the resultant coplymers could be effectively improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of honeycomb films from nitryl poly(ether ether ketone)s via water‐droplet templating

The fabrication of honeycomb‐patterned films from nitryl poly(ether ether ketone)s (PEEK‐NO₂) in a high‐humidity atmosphere was reported in this article. PEEK‐NO₂ was prepared through acid (nitric acid and sulfuric acid) nitration from poly(ether ether ketone)s (PEEK). The obtained polymer, which was characterized by Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), and differential scanning calorimetry (DSC) showed excellent solubility and thermal stability. Some influence factors on the pattern formation and the fabrication of the porous structure, such as the solution concentration, the solvent, and the atmosphere humidity, were investigated. The results showed that with the increase of the solution concentration, the aperture of the film diminished gradually; the lower the solvents´ boiling point were, the smaller the films´ apertures were and the more regular the pores´ arrange; only under high‐humidity circumstances could obvious and ordered honeycomb films be formed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Coloring of radiation damages in ion‐implanted poly(aryl ether ether ketone): LiCl uptake and thermal desorption

Poly(aryl ether ether ketone) (PEEK) films irradiated with 2 MeV O⁺ and Ar⁺ ions to fluences in the range 10¹¹–10¹³ cm^?2 were treated with 5 mol/L LiCl aqueous solution at 100°C for 1 h. After removal of excessive, weakly bound LiCl the samples were annealed at temperatures from 50 to 250°C for 1 h to check the mobility of the incorporated LiCl. The amount of incorporated LiCl and its depth profile were determined using the neutron depth‐profiling (NDP) technique, which makes use of the ⁶Li(n_th, ⁴He) ³H nuclear reaction. Up to the maximum annealing temperature no significant escape of the LiCl was observed. With increasing annealing temperature, a gradual migration of LiCl dopant toward the sample surface was observed on the irradiated PEEK samples. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2780–2784, 2002; DOI 10.1002/app.10253     

Synthesis and curing behavior of macrocycle‐terminated poly(aryl ether ketone)s

BACKGROUND: The introduction of poly(ether ether ketone)‐based carbon‐fiber composites accelerated the application of poly(ether ether ketone)s in advanced composite materials. In order to improve the compatibility and processability with reinforced components, polymers with low melt viscosity are preferable. RESULTS: Novel fully aromatic macrocycle‐terminated poly(aryl ether ketone)s (MCPAEKs) were prepared by condensation of macrocyclic aryl ether ketone dimers containing hydroxyphenyl groups and fluorine end‐capped poly(aryl ether ketone) oligomers. Compared with liner poly(aryl ether ketone)s, MCPAEKs showed much lower melt viscosities at low temperature. In the presence of caesium fluoride, the crosslinking reaction of MCPAEKs afforded fully aromatic thermoset poly(aryl ether ketone)s by ring‐opening reaction. CONCLUSION: The MCPAEKs exhibited high thermal stability due to their wholly aromatic structures. After crosslinking, the glass transition temperatures and complex melt viscosities of the polymers were increased greatly. Although there was some residual cesium fluoride or phenoxides produced by ring‐opening reaction, the thermoset poly(aryl ether ketone)s obtained had good thermal stability with temperatures at 5% weight loss above 475 °C. Copyright © 2009 Society of Chemical Industry     

Synthesis and properties of novel polyamides containing sulfone‐ether linkages and xanthene cardo groups

In order to obtain polyamides with enhanced solubility and processability, as well as good mechanical and thermal properties, several novel polyamides containing sulfone‐ether linkages and xanthene cardo groups based on a new diamine monomer, 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX), were investigated. The BAPX monomer was synthesized via a two‐step process consisting of an aromatic nucleophilic substitution reaction of readily available 4‐chloronitrobenzene with 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate in N,N‐dimethylformamide, followed by catalytic reduction with hydrazine and Pd/C. Four novel aromatic polyamides containing sulfone‐ether linkages and xanthene cardo groups with inherent viscosities between 0.98 and 1.22 dL g^?1 were prepared by low‐temperature polycondensation of BAPX with 4,4′‐sulfonyldibenzoyl chloride, 4,4′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride, 3,3′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride and 4,4′‐[sulfonyl‐bis(2,6‐dimethyl‐1,4‐phenyleneoxy)]dibenzoyl chloride in N,N‐dimethylacetamide (DMAc) solution containing pyridine. All these new polyamides were amorphous and readily soluble in various polar solvents such as DMAc and N‐methylpyrrolidone. These polymers showed relatively high glass transition temperatures in the range 238–298 °C, almost no weight loss up to 450 °C in air or nitrogen atmosphere, decomposition temperatures at 10% weight loss ranging from 472 to 523 °C and 465 to 512 °C in nitrogen and air, respectively, and char yields at 800 °C in nitrogen higher than 50 wt%. Transparent, flexible and tough films of these polymers cast from DMAc solution exhibited tensile strengths ranging from 78 to 87 MPa, elongations at break from 9 to 13% and initial moduli from 1.7 to 2.2 GPa. Primary characterization of these novel polyamides shows that they might serve as new candidates for processable high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry     

Thermal crosslinking behavior of poly (aryl ether ketone) copolymers containing naphthalene moieties

A series of poly[(ether ether ketone)‐co‐(ether naphthalene ether ketone)] (P(EEK‐co‐ENEK)) copolymers were heated under a variety of conditions. The thermal crosslinking behavior was monitored by differential scanning calorimetry (DSC), electron spin resonance (ESR) and wide‐angle X‐ray diffraction (WAXD). The results indicate that under a non‐oxidative environment such as nitrogen P(EEK‐co‐ENEK) is more stable, while under oxidative conditions a crosslinking reaction takes place that causes a reduction in the crystallizability of the copolymers, and an increase in the concentration of free radicals on the copolymer. ESR results suggest that the crosslinking reaction proceeds via free radicals. Subsequently two kinds of free radicals were characterized: one is an RO^? type free radical and the other is a naphthalene ring free radical. Copyright © 2004 Society of Chemical Industry     

Synthesis of novel poly(ether ketone diphenyl ketone ether ketone ketone)s by electrophilic Friedel–Crafts solution polycondensation

4,4′‐Bis(4‐phenoxybenzoyl)diphenyl was prepared by the Friedel–Crafts reaction of 4‐bromobenzoyl chloride and diphenyl followed by condensation with potassium phenoxide. Novel aromatic poly(ether ketone diphenyl ketone ether ketone ketone)s were obtained by the electrophilic Friedel–Crafts solution copolycondensation of 4,4′‐bis(4‐phenoxybenzoyl)diphenyl with a mixture of isophthaloyl chloride and terephthaloyl chloride over a wide range of isophthaloyl chloride/terephthaloyl chloride molar ratios in the presence of anhydrous aluminum chloride and N‐methylpyrrolidone in 1,2‐dichloroethane. The influence of the reaction conditions on the preparation of the copolymers was examined. The copolymers were characterized with different physicochemical techniques. Because of the incorporation of diphenyl, the resulting copolymers exhibited outstanding thermal stability. The glass‐transition temperatures were above 174°C, the melting temperatures were above 342°C, and the 5% weight loss temperatures were above 544°C in nitrogen. All these copolymers were semicrystalline and insoluble in organic solvents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

New poly(arylene ether)s containing phthalimidine group in the main chain

Five new poly(arylene ether)s containing phthalimidine group in the main chain and pendent trifluoromethyl group have been prepared by the reaction of 4,4′‐(bis‐4‐fluoro‐3‐trifluoromethylphenyl)benzene (BTF) with bisphenols. Different molar ratios of N‐phenyl‐3,3‐bis(4‐hydroxyphenyl)phthalimidine (PA) and 4,4′‐isopropylidenediphenol (BPA) have been used to generate different copolymers. The polymers obtained by step growth polymerization exhibited weight‐average molecular weight upto 134,000 g/mol with a polydispersity index of 2.1–2.4. The homopolymer from BTF and PA showed very high glass transition temperature of 258°C and outstanding thermal stability upto 536°C for 5% weight loss under nitrogen. The polymers were soluble in a wide range of organic solvents. Transparent thin films of these polymers exhibited tensile strengths upto 65 MPa and elongation at break upto 45% depending on the exact repeat unit structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of novel aromatic polyamides derived from 2,2′‐bis(p‐phenoxyphenyl)‐4, 4′‐diaminodiphenyl ether

BACKGROUND: Wholly aromatic polyamides (aramids) are high‐performance polymeric materials with outstanding heat resistance and excellent chemical stabilities due to chain stiffness and intermolecular hydrogen bonding of amide groups. Synthesis of structurally well‐designed monomers is an effective strategy to prepare modified forms of these aramids to overcome lack of organo‐solubility and processability limitations. RESULTS: A novel class of wholly aromatic polyamides was prepared from a new diamine, namely 2,2′‐bis(p‐phenoxyphenyl)‐4,4′‐diaminodiphenyl ether (PPAPE), and two simple aromatic dicarboxylic acids. Two reference polyamides were also prepared by reacting 4,4′‐diaminodiphenyl ether with the same comonomers under similar conditions. M?_w and M?_n of the resultant polymers were 8.0 × 10⁴ and 5.5 × 10⁴ g mol^?1, respectively. Polymers resulting from PPAPE exhibited a nearly amorphous nature. These polyamides exhibited excellent organo‐solubility in a variety of polar solvents and possessed glass transition temperatures up to 200 °C. The 10% weight loss temperatures of these polymers were found to be up to 500 °C under a nitrogen atmosphere. The polymers obtained from PPAPE could be cast into transparent and flexible films from N,N‐dimethylacetamide solution. CONCLUSION: The results obtained show that the new PPAPE diamine can be considered as a good monomer to enhance the processability of its resultant aromatic polyamides while maintaining their high thermal stability. The observed characteristics of the polyamides obtained make them promising high‐performance polymeric materials. Copyright © 2009 Society of Chemical Industry     

Synthesis of poly(ether amide)s from p‐xylylene glycol and bis(ether nitrile)s

BACKGROUND: Poly(ether amide)s have been well studied in terms of improving the physical and thermal properties of aromatic polyamides. Poly(ether amide)s of high enough molecular weight to be useful for industrial purposes are generally difficult to prepare. The objective of this project was to introduce a simple and commercially feasible process to prepare poly(ether amide)s by a polymerization reaction at relatively low temperature. RESULTS: A series of poly(ether amide)s were prepared by direct polyamidation of p‐xylylene glycol with bis(ether nitrile)s via the Ritter reaction using concentrated H₂SO₄ in acetic acid. The synthesized poly(ether amide)s showed good solubility in polar aprotic solvents. The resultant poly(ether amide)s had inherent viscosities in the range 0.36–1.03 dL g^?1. The glass transition temperatures of the poly(ether amide)s were determined using differential scanning calorimetry to be in the range 190–258 °C. Thermogravimetric analysis data for these polymers indicated the 10% weight loss temperatures to be in the range 290–390 °C in nitrogen atmosphere. CONCLUSION: The Ritter reaction was applied for the synthesis of a variety of poly(ether amide)s with moderate to high molecular weights. This procedure provides a simple polymerization process for the convenient preparation of poly(ether amide)s in high yield at room temperature. Copyright © 2009 Society of Chemical Industry     

The sulfonation of poly(ether ether ketone) as investigated by two‐dimensional FTIR correlation spectroscopy

Fourier transform infrared and two‐dimensional correlation (2D‐COS) spectroscopies were used to follow the structural alteration occurring upon sulfonation of poly(ether ether ketone), in concentrated sulfuric acid at room temperature. With the help of high resolution and high sensitivity 2D‐COS, it was possible to locate the aromatic ring in which the substitution has taken place. Two new IR bands at 1288 and 1320 cm^?1 were attributed to substitution occurring on the aromatic ring flanked with two ether groups. Limited oxidation effects of concentrated sulfuric acid manifested itself by the production of new carbonyl species absorbing in the IR at 1720 and 1750 cm^?1 that were attributed to a fluorenone‐type structure and to ester groups. The 2D‐COS analysis showed that the band at 1470 cm^?1 is not only due to the new substitution by sulfone groups and can not be used in the determination of sulfonation degree. Instead, the intensity of the 1490 cm^?1 band, which can be attributed to skeletal ring vibration, was found to correlate well with the degree of sulfonation calculated from ¹H NMR spectroscopy. The infrared spectroscopy combined with 2D‐COS provides a fast and powerful method for qualitative polymer structure verification and help to establish the quantitative analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41242.     

Synthesis and characterization of soluble poly(ether imide)s containing fluorenyl cardo groups

Two series of poly(ether imide)s (PEIs) containing fluorenyl cardo groups in the main chains were synthesized, which are derived from the polycondensation of 9,9′‐bis(4‐aminophenoxyphenyl)fluorene (BAOFL) or 9,9′‐bis(3‐trifluoromethyl,4‐aminophenoxyphenyl)fluorene (6F‐BAOFL) with four kinds of dianhydrides (3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 4,4′‐oxydiphthalicanhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, and bisphenol‐A dianhydride), respectively. The PEI films and PEI powder were prepared by thermal and chemical imidization, respectively. The PEIs were characterized by FTIR, ¹H‐NMR, differential scanning calorimetry, thermogravimetric analysis, and UV–vis were performed on inherent viscosity, solubility, and tensile tests. The effects of fluorenyl cardo groups and ether linkages on the solubility, tensile properties, thermal stability, and optical properties were investigated in detail. It was found that the PEIs had good solubility in common organic solvents and good optical transparency in visible light region. In addition, the PEI films exhibited excellent tensile and thermal properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009