Synthesis and properties of poly(arylene ether)s based on 3‐pentadecyl 4,4'‐biphenol

A new biphenol, 3‐pentadecyl 4,4′‐biphenol, was synthesized starting from 3‐pentadecylphenol and was polycondensed with 4,4′‐difluorobenzophenone, 1,3‐bis(4‐fluorobenzoyl)benzene and bis(4‐fluorophenyl)sulfone to obtain poly(arylene ether)s with biphenylene linkages in the backbone and pendent pentadecyl chains. Inherent viscosities and number‐average molecular weights (M_n) of the poly(arylene ether)s were in the range 0.50 ? 0.81 dL g^?1 and 2.2 × 10⁴ ? 8.3 × 10⁴, respectively. Detailed NMR spectroscopic studies of the poly(arylene ether)s indicated the presence of constitutional isomerism which existed because of the non‐symmetrical structure of 3‐pentadecyl 4,4′‐biphenol. The poly(arylene ether)s readily dissolved in common organic solvents such as dichloromethane, chloroform and tetrahydrofuran and could be cast into tough, transparent and flexible films from their chloroform solutions. The poly(arylene ether)s exhibited T_g values in the range 35–60 °C which are lower than that of reference poly(arylene ether)s without pentadecyl chains. The 10% decomposition temperatures (T₁₀) of the poly(arylene ether)s were in the range 410–455 °C indicating their good thermal stability. A gas permeation study of poly(ether sulfone) containing pendent pentadecyl chains revealed a moderate increase in permeability for helium, hydrogen and oxygen. However, there was a large increase in permeability for carbon dioxide which could be attributed to the internal plasticization effect of pendent pentadecyl chains. © 2016 Society of Chemical Industry     

New poly(1,3,4‐oxadiazole)s bearing pentadecyl side chains: Synthesis and characterization

The 4‐[4′‐(Hydrazinocarbonyl)phenoxy]‐2‐pentadecylbenzohydrazide was polycondensed with aromatic diacid chlorides viz., terephthalic acid chloride (TPC), isophthalic acid chloride (IPC), and a mixture of TPC : IPC (50 : 50 mol %) to obtain polyhydrazides which on subsequent cyclodehydration reaction in the presence of phosphoryl chloride yielded new poly(1,3,4‐oxadiazole)s bearing flexibilizing ether linkages and pentadecyl side chains. Inherent viscosities of polyhydrazides and poly(1,3,4‐oxadiazole)s were in the range 0.53–0.66 dL g^?1 and 0.49–0.53 dL g^?1, respectively, indicating formation of medium to reasonably high molecular weight polymers. The number average molecular weights (M_n) and polydispersities (M_w/M_n) of poly(1,3,4‐oxadiazole)s were in the range 14,660–21,370 and 2.2–2.5, respectively. Polyhydrazides and poly(1,3,4‐oxadiazole)s were soluble in polar aprotic solvents such as N,N‐dimethylacetamide, 1‐methyl‐2‐pyrrolidinone, and N,N‐dimethylformamide. Furthermore, poly(1,3,4‐oxadiazole)s were also found to be soluble in solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, and m‐cresol. Transparent, flexible, and tough films of polyhydrazides and poly(1,3,4‐oxadiazole)s could be cast from N,N‐dimethylacetamide and chloroform solutions, respectively. Both polyhydrazides and poly(1,3,4‐oxadiazole)s were amorphous in nature and formation of layered structure was observed due to packing of pentadecyl chains. A decrease in glass transition temperature was observed both in polyhydrazides (143–166°C) and poly(1,3,4‐oxadiazole)s (90–102°C) which could be ascribed to “internal plasticization” effect of pentadecyl chains. The T₁₀ values, obtained from TG curves, for poly(1,3,4‐oxadiazole)s were in the range of 433–449°C indicating their good thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124:1281–1289, 2012     

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     

Synthesis and characterization of novel soluble poly(ether ketone sulfone)s with pendant polychloro groups

A novel monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175–180°C for 10 h and confirmed by FTIR, MS, and elemental analysis. Five new polychloro substituted poly(aryl ether ketone sulfone)s (PEKSs) with inherent viscosities of 0.68–0.75 dL/g have been prepared from 4,4′‐diphenoxydiphenylsulfone, 4,4′‐bis(2‐methylphenoxy) diphenylsulfone, 4,4′‐bis(3‐methylph‐enoxy)diphenylsulfone, 4,4′‐bis(2,6‐dimethylphenoxy)diphenylsulfone, and 4,4′‐bis(1‐naphthoxy)‐diphenylsulfone with TCTPC by electrophilic Friedel‐Crafts acylation in the presence of DMF with anhydrous AlCl₃ as a catalyst in 1,2‐dichloroethane, respectively. These polymers having weight–average molecular weight in the range of 76,600–83,900 are all amorphous and show high glass transition temperatures ranging from 213 to 250°C, the 5% weight loss temperature over 450°C, high char yields of 60–67% at 700°C in nitrogen and good solubility in CHCl₃ and polar solvents such as DMF, DMSO, and NMP at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 85.1–90.8 MPa, Young's moduli of 2.52–3.24 GPa, and elongations at break of 21.2–27.2%. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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 poly(aryl ether ketone ketone)/poly(aryl ether ether ketone ketone) copolymers with pendant cyano groups

2,6‐Diphenoxybenzonitrile (DPOBN) was synthesized by reaction of phenol with 2,6‐difluorobenzonitrile in N‐methyl‐2‐pyrrolidone in the presence of KOH and K₂CO₃. Poly(aryl ether ketone ketone)/poly(aryl ether ether ketone ketone) copolymers with pendant cyano groups were prepared by the Friedel–Crafts electrophilic substitution reaction of terephthaloyl chloride with varying mole proportions of diphenyl ether and DPOBN using 1,2‐dichloroethane as solvent and N‐methyl‐2‐pyrrolidone as Lewis base in the presence of anhydrous AlCl₃. The resulting polymers were characterized by various analytical techniques, such as FT‐IR, differential scanning calorimeter, thermal gravimetric analysis, and wide‐angle X‐ray diffraction. The crystallinity and melting temperature of the polymers were found to decrease with increase in concentration of the DPOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 514°C in N₂ atmosphere. The glass transition temperature was found to increase with increase in concentration of the DPOBN units in the polymer when the molar ratios of DPOBN to DPE ranged from 10/90 to 30/70. The copolymers containing 30–40 mol % of the DPOBN units exhibit excellent thermostability at (350 ± 10)°C and have good resistance to acidity, alkali, and organic solvents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3601–3606, 2007     

Synthesis and characterization of novel soluble cardo poly(arylene ether ketone)s containing xanthene structures

9,9‐Bis(4‐hydroxyphenyl)xanthene (BHPX), a bisphenol monomer, was synthesized in 82% yield from xanthenone in a one‐pot, two‐step synthetic procedure. Four novel aromatic poly(ether ketone)s (PEKs) based on BHPX were prepared via a nucleophilic aromatic substitution polycondensation with four difluorinated aromatic ketones. The polycondensation proceeded in tetramethylene sulfone in the presence of anhydrous potassium carbonate and afforded the new cardo PEKs in nearly quantitative yields with inherent viscosities of 0.77–0.85 dL/g. High molecular weight PEKs having number‐average molecular weights (M_n's) in the range of 38,900–40,600 g/mol with the polydispersity index ranged from 1.97 to 2.06 are all amorphous and show high glass transition temperatures ranging from 210°C to 254°C, excellent thermal stability, and the temperatures at the 5% weight loss are over 538°C with char yields above 60% at 700°C in nitrogen. These new PEKs are all soluble in polar aprotic solvents such as N‐methyl‐2‐pyrrolidone and N, N′‐dimethylacetamide and could also be dissolved in chloroform and tetrahydrofuran. All the polymers formed transparent, strong, and flexible films with tensile strengths of 78–84 MPa, Young's moduli of 2.54–3.10 GPa, and elongations at break of 14–18 %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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 properties of novel organosoluble aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkages

Several novel aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkages with inherent viscosities of 0.62–0.65 dL/g were prepared from 2‐methyldiphenylether and 3‐methyldiphenylether with 4,4′‐bis(4‐chloroformylphenoxy)diphenylsulfone and 4,4′‐bis (3‐chloroformylphenoxy)diphenylsulfone by electrophilic Friedel–Crafts acylation in the presence of N,N‐dimethylformamide with anhydrous AlCl₃ as a catalyst in 1,2‐dichloroethane. These polymers, having weight‐average molecular weights in the range of 57,000–71,000, were all amorphous and showed high glass‐transition temperatures ranging from 160.5 to 167°C, excellent thermal stability at temperatures over 450°C in air or nitrogen, high char yields of 52–57% in nitrogen, and good solubility in CHCl₃ and polar solvents such as N,N‐dimethylformamide, dimethyl sulfoxide, and N‐methyl‐2‐pyrrolidone at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 84.6–90.4 MPa, Young's moduli of 2.33–2.71 GPa, and elongations at break of 26.1–27.4%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and thermotropic liquid‐crystalline behaviour of novel main‐chain poly(ether ether ketone ketone)s containing a lateral tert‐butyl group

The synthesis of novel poly(ether ether ketone ketone)s containing a lateral group via the random copolymerization of 4,4′‐biphenol, tert‐butylhydroquinone and 1,4‐bis(p‐fluorobenzoyl)benzene is described. The copolymers were characterized by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and polarized optical microscopy (POM) observation. The results showed that the thermotropic liquid‐crystalline properties were achieved in the copolymers containing 30 mol% and 50 mol% tert‐butylhydroquinone, which have relatively lower melting temperatures due to the copolymerization effect. Both the crystalline–liquid‐crystalline transition (T_m) and the liquid‐crystalline–isotropic phase transition (T_i) were observable in the DSC thermograms, while the biphenol‐based poly(aryl ether ketone) has only one melting transition. The hydroquinone‐based polymer was shown to be amorphous. Thermogravimetric analysis (TGA) results showed that these copolymers are all high‐temperature resistant with higher glass transition temperature between 147 and 149 °C, and higher decomposition temperature T_d in the range 480–520 °C. © 2000 Society of Chemical Industry     

Fine poly(ether ether ketone) powders

The physical form of polymers is often important for carrying out subsequent processing operations. For example, fine powders are desirable for molding and sintering compounds because they consolidate to produce void free components. The objective of this work is to prepare fine polymeric particulates suitable for processing into fiber reinforced polymer matrix composites. Micron size particles of poly(ether ether ketone) (PEEK) were prepared by rapidly quenching solutions of these materials. PEEK pellets were dissolved at temperatures near the PEEK melting point in a mixture of terphenyls and quaterphenyls; then the solution was quenched to a temperature between the T_g and T_m (≈ 225°C) by adding a room temperature eutectic mixture of diphenyl ether and biphenyl. A supersaturated, metastable solution of PEEK resulted, causing rapid nucleation. Fine PEEK particles rapidly crystallized from this solution. The average particle size was measured using transmission electron microscopy, atomic force microscopy, and by light scattering of aqueous suspensions which had been fractionated by centrifugation. The average particle diameter was about 0.6 μm. Three dimensional photomicrographs obtained via atomic force microscopy showed some aggregates in the suspensions. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1571–1578, 1997     

Synthesis and characterization of novel poly(aryl ether ketone ketone)s containing the o‐dibenzobene moiety

The synthesis of a novel chloro monomer containing the 1,2‐dibenzoylbenzene moiety was described. The chloro monomer was reacted with 4‐(4‐hydroxyphenyl)‐1(2H)‐phthalazinone compound in the presence of excess anhydrous potassium carbonate in an aprotic solvent (Sulfolane), and high molecular weight amorphous poly(aryl ether ketone ketone) was synthesized. The polymers with high glass transition temperature were soluble in solvents such as chloroform and nitrobenzene at room temperature and easily cast into flexible, colorless, and transparent films. The 5% weight loss of the polymers was >400 °C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1487–1492, 2001     

Synthesis and characterization of soluble poly(arylene ether ketone)s with high glass transition temperature based on 3,6‐bi(4‐fluorobenzoyl)‐N‐alkylcarbazole

3,6‐bi(4‐fluorobenzoyl)‐N‐methylcarbazole and 3,6‐bi(4‐fluorobenzoyl)‐N‐ethylcarbazole were synthesized and used to prepare poly(arylene ether ketone)s (PAEKs) with high glass transition temperatures (T_g) and good solubility. High molecular weight amorphous PAEKs were prepared from these two difluoroketones with hydroquinone, phenolphthalein, 9,9‐bis(4‐hydroxyphenyl)fluorene and 4‐(4‐hydroxylphenyl)‐2,3‐phthalazin‐1‐one, respectively. All these polymers presented high thermal stability with glass transition temperatures being in the range 239–303 °C and a 5% thermal weight loss temperature above 460 °C. Compared with the T_g of phenolphthalein‐based PAEK (PEK‐C), fluorene‐based PAEK (BFEK) and phthalazinone‐based PAEK (DPEK) not containing a carbazole unit, these polymers presented a 30–50 °C increase in T_g. Meanwhile, PAEKs prepared from N‐ethylcarbazole difluoroketone showed good solubility in ordinary organic solvents, and all polymers exhibited excellent resistance to hydrochloric acid (36.5 wt%) and sodium hydroxide (50 wt%) solutions. In particular, phthalazinone‐based PAEK bearing N‐ethylcarbazole afforded simultaneously a T_g of 301 °C with good solubility. Tensile tests of films showed that these polymers have desirable mechanical properties. The carbazole‐based difluoroketones play an important role in preparing soluble PAEKs with high T_g by coordinating the relationship between chain rigidity resulting from the carbazole unit and chain distance from the side alkyl. © 2014 Society of Chemical Industry     

Synthesis and characterization of poly(ether amide ether ketone)/poly(ether ketone ketone) copolymers

A new monomer, N,N′‐bis(4‐phenoxybenzoyl)‐m‐phenylenediamine (BPPD), was prepared by condensation of m‐phenylenediamine with 4‐phenoxybenzoyl chloride in N,N‐dimethylacetamide (DMAc). A series of novel poly(ether amide ether ketone) (PEAEK)/poly(ether ketone ketone) (PEKK) copolymers were synthesized by the electrophilic Friedel‐Crafts solution copolycondensation of terephthaloyl chloride (TPC) with a mixture of diphenyl ether (DPE) and BPPD, over a wide range of DPE/BPPD molar ratios, in the presence of anhydrous AlCl₃ and N‐methylpyrrolidone (NMP) in 1,2‐dichloroethane (DCE). The influence of reaction conditions on the preparation of copolymers was examined. The copolymers obtained were characterized by different physicochemical techniques. The copolymers with 10–25 mol % BPPD were semicrystalline and had remarkably increased T_gs over commercially available PEEK and PEKK due to the incorporation of amide linkages in the main chains. The copolymers III and IV with 20–25 mol % BPPD had not only high T_gs of 184–188°C, but also moderate T_ms of 323–344°C, having good potential for the melt processing. The copolymers III and IV had tensile strengths of 103.7–105.3 MPa, Young's moduli of 3.04–3.11 GPa, and elongations at break of 8–9% and exhibited outstanding thermal stability and good resistance to organic solvents. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

Synthesis and characterization of poly(ether ketone ketone) (PEKK)/sodium sulfonated poly(arylene ether ketone) (S‐PAEK) block copolymers

A series of well‐defined poly(ether ketone ketone) (PEKK)/sodium sulfonated poly(aryl ether ketone) (S‐PAEK) block copolymers of high molecular weights was prepared by direct nucleophilic polymerization of hydroquinone with sodium 5,5′‐carbonylbis(2‐fluorobenzene sulfonate) ( 1 ) and PEKK oligomer ( 2 ). Varying the ratio of 1 to 2 used in polymerization can be used to control the degree of polymer sulfonation, which correspondingly affects the polymer solubility in solvents. Increasing content of 1 in the copolymers, slightly decreases their thermal stability which is nevertheless thermally stable up to 400 °C. Two T_g values, or one broad T_g, were observed in the DSC measurements of the block copolymers, indicating the existence of phase separation, which was further proved by phase‐separated morphologies as shown in atomic force microscopy images. © 2001 Society of Chemical Industry     

Synthesis and properties of organic soluble semicrystalline poly(aryl ether ketone)s copolymers containing phthalazinone moieties

A series of poly(aryl ether ketone)s (PAEK) copolymers containing phthalazinone moieties were synthesized by modest polycondensation reaction from 4‐(4‐hydroxyl‐phenyl)‐(2H)‐phthalazin‐1‐one (DHPZ), hydroquinone (HQ), and 1,4‐bis(4‐fluorobenzoyl)benzene (BFBB). The T_g values of these copolymers ranged from 168 to 235°C, and the crystalline melting temperatures varied from 285 to 352°C. By introducing phthalazinone moieties into the main chain, the solubility of these copolymers was improved in some common polar organic solvents, such as chloroform (CHCl₃), N‐methyl‐2‐pyrrolidinone (NMP), nitrobenzene (NB) and so on. The values of 5% weight loss temperatures were all higher than 510°C in nitrogen. The crystal structures of these copolymers were determined by wide‐angle X‐ray diffraction (WAXD), which revealed that they were semicrystalline in nature, and the crystal structure of these copolymers was orthorhombic, equal to poly(ether ether ketone ketone)s. As phthalazinone content in the backbone varied from 0 to 40 mol % (mole percent), the cell parameters of these copolymers including the a, b, and c axes lengths ranged from 7.76 to 7.99 Å, 6.00 to 6.14 Å, and 10.10 to 10.19 Å, respectively. The degree of crystallinity (via differential scanning calorimetry) decreased from 37.70% to 16.14% simultaneously. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1744–1753, 2007     

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     

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 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