Synthesis and characterization of new soluble poly(ester‐imide)s containing noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit

A new diimide–diacid chloride (3) containing a noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit was synthesized by treating 2,2′‐dimethyl‐4,4′‐diamino‐biphenylene with trimellitic anhydride followed by refluxing with thionyl chloride. Various new poly(ester‐imide)s were prepared from 3 with different bisphenols by solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher at 170°C. Inherent viscosities of the poly(ester‐imide)s were found to range between 0.31 and 0.35 dL g^?1. All of the poly(ester‐imide)s, except the one containing pendent adamantyl group 5e, exhibited excellent solubility in the following solvents: N,N‐dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidinone, m‐cresol, o‐chlorophenol, and chloroform. The polymers showed glass‐transition temperatures between 166 and 226°C. The 10% weight loss temperatures of the poly(ester‐imide)s, measured by TGA, were found to be in the range between 415 and 456°C in nitrogen. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2486–2493, 2004     

Biodegradable polymers based on renewable resources. V. Synthesis and biodegradation behavior of poly(ester amide)s composed of 1,4:3,6‐dianhydro‐D‐glucitol, α‐amino acid,and aliphatic dicarboxylic acid units

A series of poly(ester amide)s were synthesized by solution polycondensations of various combinations of p‐toluenesulfonic acid salts of O,O′‐bis(α‐aminoacyl)‐1,4:3,6‐dianhydro‐D ‐glucitol and bis(p‐nitrophenyl) esters of aliphatic dicarboxylic acids with the methylene chain lengths of 4–10. The p‐toluenesulfonic acid salts were obtained by the reactions of 1,4:3,6‐dianhydro‐D ‐glucitol with alanine, glycine, and glycylglycine, respectively, in the presence of p‐toluenesulfonic acid. The polycondensations were carried out in N‐methylpyrrolidone at 40°C in the presence of triethylamine, giving poly(ester amide)s having number‐average molecular weights up to 3.8 × 10⁴. Their structures were confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. Most of these poly(ester amide)s are amorphous, except those containing sebacic acid and glycine or glycylglycine units, which are semicrystalline. All these poly(ester amide)s are soluble in a variety of polar solvents such as dimethyl sulfoxide, N,N‐dimethylformamide, 2,2,2‐trifluoroethanol, m‐cresol, pyridine, and trifluoroacetic acid. Soil burial degradation tests, BOD measurements in an activated sludge, and enzymatic degradation tests using Porcine pancreas lipase and papain indicated that these poly(ester amide)s are biodegradable, and that their biodegradability markedly depends on the molecular structure. The poly(ester amide)s were, in general, degraded more slowly than the corresponding polyesters having the same aliphatic dicarboxylic acid units, both in composted soil and in an activated sludge. In the enzymatic degradation, some poly(ester amide)s containing dicarboxylic acid components with shorter methylene chain lengths were degraded more readily than the corresponding polyesters with Porcine pancreas lipase, whereas most of the poly(ester amide)s were degraded more rapidly than the corresponding polyesters with papain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2721–2734, 2001     

Synthesis and characterization of new thermally stable poly(ester‐imide)s derived from 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl and 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl and various aromatic dihydroxy compounds

A series of new alternating aromatic poly(ester‐imide)s were prepared by the polycondensation of the preformed imide ring‐containing diacids, 2,2′‐bis(4‐trimellitimidophenoxy)biphenyl (2a) and 2,2′‐bis(4‐trimellitimidophenoxy)‐1,1′‐binaphthyl (2b) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A model compound (3) was also prepared by the reaction of 2b with phenol, its synthesis permitting an optimization of polymerization conditions. Poly(ester‐imides) were fully characterized by FTIR, UV‐vis and NMR spectroscopy. Both biphenylene‐ and binaphthylene‐based poly(ester‐imide)s exhibited excellent solubility in common organic solvents such as tetrahydrofuran, m‐cresol, pyridine and dichloromethane. However, binaphthylene‐based poly(ester‐imide)s were more soluble than those of biphenylene‐based polymers in highly polar organic solvents, including N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide and dimethyl sulfoxide. From differential scanning calorimetry thermograms, the polymers showed glass‐transition temperatures between 261 and 315 °C. Thermal behaviour of the polymers obtained was characterized by thermogravimetric analysis, and the 10 % weight loss temperatures of the poly(ester‐imide)s was in the range 449–491 °C in nitrogen. Furthermore, crystallinity of the polymers was estimated by means of wide‐angle X‐ray diffraction. The resultant poly(ester‐imide)s exhibited nearly an amorphous nature, except poly(ester‐imide)s derived from hydroquinone and 4,4′‐dihydroxybiphenyl. In general, polymers containing binaphthyl units showed higher thermal stability but lower crystallinity than polymers containing biphenyl units. Copyright © 2005 Society of Chemical Industry     

Preparation and characterization of poly(silyl ester)s containing 2,2‐bis(p‐dimethylsiloxy‐phenyl)propane units in the polymer backbones

The two poly(silyl ester)s containing 2,2‐bis(p‐dimethylsiloxy‐phenyl)propane units in the polymer backbones have been prepared via polycondensation reaction of di‐tert‐butyl adipate and di‐tert‐butyl fumarate with 2,2‐bis(p‐chloro dimethylsiloxy‐phenyl)propane to give tert‐butyl chloride as the condensate. The polymerizations were performed under nitrogen at 110°C for 24 h without addition of solvents and catalysts to obtain the poly(silyl ester)s with weight average molecular weights typically ranging from 5000 to 10,000 g/mol. Characterization of the poly(silyl ester)s included ¹H NMR and ¹³C NMR spectroscopies, infrared spectroscopy, ultraviolet spectroscopy, differential scanning calorimetry, thermogravimetric analysis (TGA), gel permeation chromatography, and Ubbelohde viscometer. The glass transition temperatures (T_g) of the obtained polymers were above zero because of the introducing 2,2‐bis(p‐dimethylsiloxy‐phenyl)propane units in the polymer backbones. The TGA/DTG results showed that the obtained poly(silyl ester)s were stable up to 180°C and the residual weight percent at 800°C were 18 and 9%, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1937–1942, 2006     

Synthesis and characterization of poly(ester‐ether‐imide)s derived from 5‐(4‐trimellitimidophenoxy)‐1‐trimellitimido naphthalene

A series of novel aromatic poly(ester‐ether‐imide)s with inherent viscosity values of 0.44–0.74 dL g^?1 were prepared by the diphenylchlorophosphate‐activated direct polycondensation of an imide ring‐containing diacid namely 5‐(4‐trimellitimidophenoxy)‐1‐trimellitimido naphthalene ( 1 ) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. Owing to comparison of the characterization data, an ester‐containing model compound ( 2 ) was also synthesized by the reaction of 1 with phenol. The model compound 2 and the resulted polymers were fully characterized by FT‐IR and NMR spectroscopy. The ultraviolet λ_max values of the poly(ester‐ether‐imide)s were also determined. The resulting polymers exhibited an excellent organosolubility in a variety of high polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, and N‐methyl‐2‐pyrrolidone. They were soluble even in common less polar organic solvents such as pyridine, m‐cresol, and tetrahydrofuran on heating. Crystallinity of the polymers was estimated by means of wide‐angle X‐ray diffraction. The resulted polymers exhibited nearly an amorphous nature. From differential scanning calorimetry thermograms, the polymers showed glass‐transition temperatures between 221 and 245°C. Thermal behaviors of the obtained polymers were characterized by thermogravimetric analysis, and the 10% weight loss temperatures of the poly(ester‐ether‐imide)s were found to be over 410°C in nitrogen. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Direct synthesis of poly(4′‐oxy‐4‐biphenylcarbonyl) and poly(2‐oxy‐6‐naphthoyl) under nonstoichiometric conditions

Direct synthesis of poly(4′‐oxy‐4‐biphenylcarbonyl) (POBP) and poly(2‐oxy‐6‐naphthoyl) (PON) was examined by polycondensation of 4′‐hydroxy‐4‐biphenylcarboxylic acid (HBPA) and 2‐hydroxy‐6‐naphthoic acid (HNA) in the presence of 4‐ethoxybenzoic anhydride or 2‐naphthoic anhydride as condensation reagents. Polymerizations were carried out at 320 °C in aromatic solvents and liquid paraffin. POBP, having a number‐average degree of polymerization (DPn) of 38, was obtained as plate‐like crystals at the molar ratio of HBPA and anhydride of 50 mol%. PON was also obtained as plate‐like crystals but the DPn was only 13. HBPA and HNA were first converted to reactive acyloxyaromatic acid intermediates. Then the DPn was increased by means of reaction‐induced crystallization of oligomers and subsequent solid‐state polymerization via an acid–ester exchange under nonstoichiometric conditions caused by the monocarboxylic acid by‐product. Even though the DPn of PON was not as high, direct polycondensation of HBPA and HNA proceeded successfully with aromatic anhydrides. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of novel optically active poly(amide–imide)s containing N,N′‐(pyromellitoyl)‐bis‐L‐valine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation

Pyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) was reacted with L ‐valine in a mixture of acetic acid and pyridine (3:2) at room temperature, and then was refluxed at 90–100 °C, N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid was obtained in quantitative yield. The imide–acid was converted to N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid chloride by reaction with thionyl chloride. Rapid and highly efficient synthesis of a number of poly(amide–imide)s was achieved under microwave irradiation using a domestic microwave oven by polycondensation of N,N′‐(pyromellitoyl)‐bis‐L ‐valine diacid chloride with six different derivatives of 5,5‐disubstituted hydantoin compounds in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. A suitable organic medium was o‐cresol. The polycondensation proceeded rapidly, compared with conventional melt polycondensation and solution polycondensation and was almost completed within 8 min, giving a series of poly(amide–imide)s with inherent viscosities in the range 0.15–0.36 dl g^?1. The resulting poly(amide–imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by Fourier‐transform infrared (FT‐IR) spectroscopy, elemental analysis, inherent viscosity (η_inh) measurements, solubility testing and specific rotation measurements. The thermal properties of the poly(amide–imide)s were investigated by using thermogravimetric analysis. Copyright © 2004 Society of Chemical Industry     

Synthesis of poly(ester‐anhydride)s based on poly(ϵ‐caprolactone) prepolymer

The objective of this study was to prepare high molecular weight poly(ester‐anhydride)s by melt polycondensation. The polymerization procedure consisted of the preparation of carboxylic acid terminated poly(?‐caprolactone) prepolymers that were melt polymerized to poly(?‐caprolactone)s containing anhydride functions along the polymer backbone. Poly(?‐caprolactone) prepolymers were prepared using either 1,4‐butanediol or 4‐(hydroxymethyl)benzoic acid as initiators, yielding hydroxyl‐terminated intermediates that were then converted to carboxylic acid‐terminated prepolymers by reaction with succinic anhydride. Prepolymers were then allowed to react with an excess of acetic anhydride, followed by subsequent polycondensation to resulting high molecular weight poly(ester‐anhydride)s. Upon coupling of prepolymers, size exclusion chromatography analyses showed an increase from 3600 to 70,000 g/mol in number‐average molecular weight (M_n) for the 1,4‐butanediol initiated polymer, and an increase from 7200 to 68,000 g/mol for the 4‐(hydroxymethyl)benzoic acid‐initiated polymer. 4‐Hydroxybenzoic acid and adipic acid were also used as initiators in the preparation of poly(?‐caprolactone) prepolymers. However, with these initiators, the results were not satisfactory. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 176–185, 2001     

Synthesis and biodegradability evaluation of 2‐methylene‐1,3‐dioxepane and styrene copolymers

Biodegradable copolymers of 2‐methylene‐1,3‐dioxepane (MDO) and styrene (ST) were synthesized by free‐radical copolymerization using di‐t‐butyl peroxide (DTBP) as the initiator. The copolymers containing ester units were characterized by Fourier transform infrared (FTIR), ¹H‐NMR, and ¹³C‐NMR spectroscopy. Their molecular weight and polydispersity index were determined by gel permeation chromatography (GPC). In vitro enzymatic degradation of poly(MDO‐co‐ST) was performed at 37°C in phosphate buffer solution (PBS, pH = 7.4) in the presence of Pseudomonas lipase or crude enzyme extracted from earthworm. The experiment showed that incorporating ester units into C? C backbone chain of polystyrene would result in a biodegradable copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1146–1151, 2007     

Novel organosoluble poly(amide‐imide‐imide)s synthesized from new tetraimide‐dicarboxylic acid by condensation with 4,4′‐oxydiphthalic anhydride, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene,trimellitic anhydride,and various aromatic diamines

A new monomer of tetraimide‐dicarboxylic acid (IV) was synthesized by starting from ring‐opening addition of 4,4′‐oxydiphthalic anhydride, trimellitic anhydride, and 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene at a 1:2:2 molar ratio in N‐methyl‐2‐pyrrolidone (NMP). From this new monomer, a series of novel organosoluble poly(amide‐imide‐imide)s with inherent viscosities of 0.7–0.96 dL/g were prepared by triphenyl phosphite activated polycondensation from the tetraimide‐diacid with various aromatic diamines. All synthesized polymers were readily soluble in a variety of organic solvents such as NMP and N,N‐dimethylacetamide, and most of them were soluble even in less polar m‐cresol and pyridine. These polymers afforded tough, transparent, and flexible films with tensile strengths ranging from 99 to 125 MPa, elongations at break from 12 to 19%, and initial moduli from 1.6 to 2.4 GPa. The thermal properties and stability were also good with glass‐transition temperatures of 236–276°C and thermogravimetric analysis 10 wt % loss temperatures of 504–559°C in nitrogen and 499–544°C in air. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2854–2864, 2006     

Synthesis and characterization of new poly(amide‐imide)s based on 1,4‐bis(trimellitimido)‐2,5‐dichlorobenzene

A series of new aromatic poly(amide‐imide)s were synthesized by the triphenyl phosphite‐activated polycondensation of the diimide‐diacid, 1,4‐bis(trimellitimido)‐2,5‐dichlorobenzene (I), with various aromatic diamines in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP), pyridine, and calcium chloride. The poly(amide‐imide)s had inherent viscosities of 0.88–1.27 dL g⁻¹. The diimide‐diacid monomer (I) was prepared from 2,5‐dichloro‐p‐phenylenediamine with trimellitic anhydride. All the resulting polymers were amorphous and were readily soluble in a variety of organic solvents, including NMP and N,N‐dimethylacetamide. Transparent, flexible, and tough films of these polymers could be cast from N,N‐dimethylacetamide or NMP solutions. Cast films had tensile strengths ranging from 92 to 127 MPa, elongations at break from 4 to 24%, and initial moduli from 2.59 to 3.65 GPa. The glass transition temperatures of these polymers were in the range of 256°–317°C, and the 10% weight loss temperatures were above 430°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 271–278, 1999     

Poly(amide‐ester)s derived from dicarboxylic acid and aminoalcohol

A series of alternating aliphatic poly(amide‐ester)s, derived from dicarboxylic acid and aminoalcohols, were obtained by polycondensation in melt. All poly(amide‐ester)s were characterized by FTIR and ¹H/¹³C‐NMR spectroscopies. The synthesized polymers showed an inherent viscosity ranging from 0.4 to 1.0 dL g^?1. Thermal analysis showed melting points within the range 100–115°C and glass transition within the range 30–60°C. Decomposition temperatures were more than 200°C higher than the corresponding melting temperatures. The polymers can thus be processed from the melt. The processed polymers were partially crystalline with good thermal stability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 362–368, 2005     

Phosphorus‐containing poly(ester‐imide)–polydimethylsiloxane copolymers

New phosphorus‐containing poly(ester‐imide)‐polydimethylsiloxane copolymers were prepared by solution polycondensation of 1,4‐[2‐(6‐oxido‐6H‐dibenz < c,e > < 1, 2 > oxaphosphorin‐6‐yl)]naphthalene‐bis(trimellitate) dianhydride with a mixture of an aromatic diamine (1,3‐bis(4‐aminophenoxy)benzene) and α,ω‐bis(3‐aminopropyl)oligodimethylsiloxane of controlled molecular weight, in various ratios. Poly(amic acid) intermediates were converted quantitatively to the corresponding polyimide structures using a solution imidization procedure. The polymers are easily soluble in polar organic solvents, such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylformamide, as well as in less polar solvents such as tetrahydrofuran. They show good thermal stability, the decomposition temperature being above 370 °C. The glass transition temperatures are in the range 165–216 °C. Solutions of the polymers in N‐methyl‐2‐pyrrolidone exhibit photoluminescence in the blue region. Copyright © 2010 Society of Chemical Industry     

Thermal degradation of poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) as studied by TG,TG–FTIR,and Py–GC/MS

The thermal degradation kinetics of poly(3‐hydroxybutyrate) (PHB) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [poly(HB–HV)] under nitrogen was studied by thermogravimetry (TG). The results show that the thermal degradation temperatures (T_o, T_p, and T_f) increased with an increasing heating rate (B). Poly(HB–HV) was thermally more stable than PHB because its thermal degradation temperatures, T_o(0), T_p(0), and T_f(0)—determined by extrapolation to B = 0°C/min—increased by 13°C–15°C over those of PHB. The thermal degradation mechanism of PHB and poly(HB–HV) under nitrogen were investigated with TG–FTIR and Py–GC/MS. The results show that the degradation products of PHB are mainly propene, 2‐butenoic acid, propenyl‐2‐butenoate and butyric‐2‐butenoate; whereas, those of poly(HB–HV) are mainly propene, 2‐butenoic acid, 2‐pentenoic acid, propenyl‐2‐butenoate, propenyl‐2‐pentenoate, butyric‐2‐butenoate, pentanoic‐2‐pentenoate, and CO₂. The degradation is probably initiated from the chain scission of the ester linkage. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1530–1536, 2003     

Synthesis and characterization of polyamides and poly(amide‐imide)s derived from 2,6‐bis(3‐aminophenoxy)benzonitrile or 2,6‐bis(4‐aminophenoxy)benzonitrile

A series of polyamides and poly(amide‐imide)s was prepared by direct polycondensation of ether and nitrile group containing aromatic diamines with aromatic dicarboxylic acids and bis(carboxyphthalimide)s respectively in N‐methyl 2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. New diamines, such as 2,6‐bis(4‐aminophenoxy)benzonitrile and 2,6‐bis(3‐aminophenoxy)benzonitrile, were prepared from 2,6‐dichlorobenzonitrile with 4‐aminophenol and 3‐aminophenol, respectively, in NMP using potassium carbonate. Bis(carboxyphthalimide)s were prepared from the reaction of trimellitic anhydride with various aromatic diamines in N,N′‐dimethyl formamide. The inherent viscosities of the resulting polymers were in the range of 0.27 to 0.93 dl g^?1 in NMP and the glass transition temperatures were between 175 and 298 °C. All polymers were soluble in dipolar aprotic solvents such as dimethylsulfoxide, dimethylacetamide and NMP. All polymers were stable up to 350 °C with a char yield of above 40 % at 900 °C in nitrogen atmosphere. All polymers were found to be amorphous except the polyamide derived from isophthalic acid and the poly(amide‐imide)s derived from diaminodiphenylether and diaminobenzophenone based bis(carboxyphthalimide)s. Copyright © 2004 Society of Chemical Industry     

Synthesis and properties of PMR type poly(benzimidazopyrrolone‐imide)s

PMR type poly(benzimidazopyrrolone‐imide) or poly(pyrrolone‐imide) (PPI) matrix resin was synthesized using the diethyl ester of 4,4′‐(hexafluoroisopropylidene)diphthalic acid (6FDE), 3,3′‐diaminobenzidine, para‐phenylenediamine, and monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid (NE) in anhydrous ethyl alcohol with N‐methylpyrrolidone. The homogeneous matrix resin solution (40–50% solid) was stable for a storage period of 2 weeks and showed good adhesion with carbon fibers, which ensured production of prepregs. The chemical and thermal processes in the polycondensation of the monomeric reactant mixture were monitored by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, etc. Thermosetting PPI as well as short carbon fiber‐reinforced polymer composites was accomplished at optimal thermal curing conditions. The polymer materials, after postcuring, showed excellent thermal stability, with an initial decomposition temperature > 540°C. Results of MDA experiments indicate that the materials showed > 70–80% retention of the storage modulus at 400°C and glass transition temperatures as high as 440–451°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1600–1608, 2001     

Synthesis and characterization of novel soluble pyridine‐containing polyimides based on 4‐phenyl‐2,6‐bis[4‐(4‐aminophenoxy)phenyl]‐pyridine and various aromatic dianhydrides

A new kind of pyridine‐containing aromatic diamine monomer, 4‐phenyl‐2,6‐bis[4‐(4‐aminophenoxy)phenyl]‐pyridine (PAPP), was successfully synthesized by a modified chichibabin reaction of benzaldehyde and a substituted acetophenone, 4‐(4‐nitrophenoxy)‐acetophenone (NPAP), followed by a reduction of the resulting dinitro compound 4‐phenyl‐2,6‐bis[4‐(4‐nitrophenoxy)phenyl]‐pyridine (PNPP) with Pd/C and hydrazine monohydrate. The aromatic diamine was employed to synthesize a series of new pyridine‐containing polyimides by polycondensation with various aromatic dianhydrides in N‐methy‐2‐pyrrolidone (NMP) via the conventional two‐step method, i.e., ring‐opening polycondensation forming the poly (amic acid)s and further thermal or chemical imidization forming polyimides. The inherent viscosities of the resulting polyimides were in the range of 0.79–1.13 dL/g, and most of them were soluble in common organic solvents such as N,N‐dimethylacetamide (DMAc), NMP, and tetrahydrofuran (THF), etc. Meanwhile, strong and flexible polyimide films were obtained, which had good thermal stability, with the glass transition temperatures (T_g) of 268–338°C and the temperature at 5% weight loss of 521–548°C in air atmosphere, as well as outstanding mechanical properties with tensile strengths of 89.2–112.1 MPa and elongations at break of 9.5–15.4%. The polyimides also were found to possess low dielectric constants ranging from 2.53 to 3.11. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 212–219, 2007     

Synthesis and characterization of new cardo poly(bisbenzothiazole)s from 1,1‐bis(4‐amino‐3‐mercaptophenyl)‐4‐tert‐butylcyclohexane dihydrochloride

A new monomer 1,1‐bis(4‐amino‐3‐mercaptophenyl)‐4‐tert‐butylcyclohexane dihydrochloride, bearing the bulky pendant 4‐tert‐butylcyclohexylidene group, was synthesized from 4‐tert‐butylcyclohexanone in three steps. Its chemical structure was characterized by ¹H NMR, ¹³C NMR, MS, FTIR, and EA. Aromatic poly(bisbenzothiazole)s (PBTs V) were prepared from the new monomer and five aromatic dicarboxylic acids by direct polycondensation. The inherent viscosities were in the range of 0.63–2.17 dL/g. These polymers exhibited good solubility and thermal stability. Most of the prepared PBTs V were soluble in various polar solvents. Thermogravimetric analysis showed the decomposition temperatures at 10% weight loss that were in the range of 495–534°C in nitrogen. All the PBTs V, characterized by X‐ray diffraction, were amorphous. The UV absorption spectra of PBTs V showed a range of λ_max from 334 to 394 nm. All the PBTs V prepared had evident fluorescence emission peaks, ranging from 423 to 475 nm with different intensity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2000–2008, 2006     

Synthesis and properties of new aromatic poly(ester‐imide)s derived from 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl) pyridine and various dihydroxy compounds

A novel class of wholly aromatic poly(ester‐imide)s, having a biphenylene pendant group, with inherent viscosities of 0.32–0.49 dL g^?1 was prepared by the diphenylchlorophosphate‐activated direct polyesterification of the preformed imide‐ring‐containing diacid, 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A reference diacid, 2,6‐bis(trimellitimido)pyridine (2) without a biphenylene pendant group and two phenylene rings in the backbone, was also synthesized for comparison purposes. At first, with due attention to structural similarity and to compare the characterization data, a model compound (3) was synthesized by the reaction of compound 1 with two mole equivalents of phenol. Moreover, the optimum condition of polymerization reactions was obtained via a study of the model compound synthesis. All of the resulting polymers were characterized by Fourier transform infrared and ¹H NMR spectroscopy and elemental analysis. The ultraviolet λ_max values of the poly(ester‐imide)s were also determined. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, chloroform, tetrahydrofuran, and m‐cresol, as well as in polar organic solvents, such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. The crystalline nature of the polymers obtained was evaluated by means of wide‐angle X‐ray diffraction. The resulting poly(ester‐imide)s showed nearly an amorphous nature, except poly(ester‐imide) derived from 4,4′‐dihydroxy biphenyl. The glass transition temperatures (T_g) of the polymers determined by differential scanning calorimetry thermograms were in the range 298–342 °C. The 10% weight loss temperatures (T_10%) from thermogravimetric analysis curves were found to be in the range 433–471 °C in nitrogen. Films of the polymers were also prepared by casting the solutions. Copyright © 2006 Society of Chemical Industry     

Synthesis and characterization of new cardo poly(ether imide)s derived from 9,9‐bis [4‐(4‐aminophenoxy)phenyl]xanthene

A series of new cardo poly(ether imide)s bearing flexible ether and bulky xanthene pendant groups was prepared from 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene with six commercially available aromatic tetracarboxylic dianhydrides in N,N‐dimethylacetamide (DMAc) via the poly(amic acid) precursors and subsequent thermal or chemical imidization. The intermediate poly(amic acid)s had inherent viscosities between 0.83 and 1.28 dL/g, could be cast from DMAc solutions and thermally converted into transparent, flexible, and tough poly(ether imide) films which were further characterized by X‐ray and mechanical analysis. All of the poly(ether imide)s were amorphous and their films exhibited tensile strengths of 89–108 MPa, elongations at break of 7–9%, and initial moduli of 2.12–2.65 GPa. Three poly(ether imide)s derived from 4,4′‐oxydiphthalic anhydride, 4,4′‐sulfonyldiphthalic anhydride, and 2,2‐bis(3,4‐dicarboxyphenyl))hexafluoropropane anhydride, respectively, exhibited excellent solubility in various solvents such as DMAc, N,N‐dimethylformamide, N‐methyl‐2‐pyrrolidinone, pyridine, and even in tetrahydrofuran at room temperature. The resulting poly(ether imide)s with glass transition temperatures between 286 and 335°C had initial decomposition temperatures above 500°C, 10% weight loss temperatures ranging from 551 to 575°C in nitrogen and 547 to 570°C in air, and char yields of 53–64% at 800°C in nitrogen. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012