Synthesis and characterization of new thermally stable aromatic copoly(ester–amide)s from diester‐dicarboxylic acids

Two new aromatic diester‐dicarboxylic acids containing furan rings, namely, benzofuro[2,3‐b]benzofuran‐2,9‐dicarboxyl‐bis‐pyridyl ester‐4,4′‐dicarboxylic acid and benzofuro[2,3‐b]benzofuran‐2,9‐dicarboxyl‐bis‐phenyl ester‐4,4′‐dicarboxylic acid were synthesized by the reaction of benzofuro[2,3‐b]benzofuran‐2,9‐dicarbonyl chloride with 6‐hydroxynicotinic acid and 4‐hydroxybenzoic acid, respectively. These monomers were converted to aromatic copoly(ester–amide)s by reaction with various aromatic diamines via direct polycondensation. Polymers were characterized by FTIR and ¹H NMR spectroscopy, thermogravimetry, viscosity and solubility tests. The inherent viscosity of the polymers was in the range 0.23–0.46 dl g^?1 in dimethyl sulfoxide at 30 °C. They dissolved readily in polar solvents at room temperature. They possess a glass‐transition temperature in the range 210–260 °C and exhibit excellent thermal stability. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of thermoplastic poly(ester–siloxane)s

Two series of thermoplastic poly(ester–siloxane)s, based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) as the hard segment, were synthesized by two‐step catalyzed transesterification reactions in the melt. Incorporation of soft poly(dimethylsiloxane) segments into the copolyester backbone was accomplished in two different ways. The first series was prepared based on dimethyl terephthalate, 1,4‐butanediol and silanol‐terminated poly(dimethylsiloxane) (PDMS‐OH). For the second series, the PDMS‐OH was replaced by methyl diesters of carboxypropyl‐terminated poly(dimethylsiloxane)s. The syntheses were optimized in terms of both the concentration of catalyst, tetra‐n‐butyl‐titanate (Ti(OBu)₄), and stabilizer, N,N′‐diphenyl‐p‐phenylene‐diamine, as well as the reaction time. The reactions were followed by measuring the inherent viscosities of the reaction mixture. The molecular structures of the synthesized poly(ester–siloxane)s were verified by ¹H NMR spectroscopy, while their thermal properties were investigated using differential scanning calorimetry. © 2001 Society of Chemical Industry     

Syntheses and properties of new poly(amide–imide)s based on 1,4‐bis(4‐aminophenoxy)naphthalene and various diimide–diacids

A series of new alternative poly(amide–imide)s (PAIs, III_a–j ) was synthesized by the direct polycondensation of 1,4‐bis(4‐aminophenoxy)naphthalene (1,4‐BAPON) with various aromatic diimide–diacids. These polymers were obtained in quantitative yields with inherent viscosities of 0.71–1.03 dL/g. Except for III_a, most of the polymers were soluble in aprotic polar solvents such as NMP, DMAc, DMF, and DMSO and could be solution‐cast into transparent, flexible, and tough films. The glass transition temperatures of these PAIs were in the range of 235–280°C. Thermogravimetric analyses established that these polymers were fairly stable up to 450°C, and 10% weight loss temperatures were recorded in the range of 520–569°C under nitrogen and 506–566°C under an air atmosphere. Compared with the PAIs with the 1,4‐bis(4‐aminophenoxy)benzene structure (series IV), the solubility of series III was better than that of series IV. Series III also exhibited lower crystallinity and better processability than those of series IV. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 217–225, 2000     

The effect of segment length on some properties of thermoplastic poly(ester–siloxane)s

A series of novel thermoplastic elastomers, based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were synthesized by catalyzed two‐step, melt transesterification reactions of dimethyl terephthalate and methyl esters of carboxypropyl‐terminated poly(dimethylsiloxane)s (M?_n = 550–2170 g mol^?1) with 1,4‐butanediol. The lengths of both the hard and soft segments were varied while the weight ratio of the hard to soft segments in the reaction mixture was maintained constant (57/43). The molecular structure, composition and molecular weights of the poly(ester–siloxane)s were examined by ¹H NMR spectroscopy. The effectiveness of the incorporation of the methyl‐ester‐terminated poly(dimethylsiloxane)s into the copolymer chains was verified by chloroform extraction. The effect of the segment length on the transition temperatures (T_m and T_g) and the thermal and thermo‐oxidative degradation stability, as well as the degree of crystallinity and hardness properties of the synthesized TPESs, were studied. Copyright © 2003 Society of Chemical Industry     

Synthesis and liquid‐crystal‐aligning properties of novel aromatic poly(amide imide)s bearing n‐alkyloxy side chains

Novel aromatic poly(amide imide)s (m‐PAIs, m = 8, 12, 16) containing preformed isophthalamide unit and pendent n‐alkyloxy (‐O‐n‐C_mH_2m+1, m = 8, 12, 16) side chains were prepared in thin films by polymerization of pyromellitic dianhydride (PMDA) with N,N′‐bis(4‐aminophenyl)‐5‐(n‐alkyloxy)isophthalamides (m‐DAs) obtained from N,N′‐bis(4‐nitrophenyl)‐5‐(n‐alkyloxy)isophthalamides (m‐DNs). The m‐PAI films were tough, flexible and transparent with inherent viscosities in the 1.25–1.67 dL/g range in DMAc and soluble in DMAc and NMP on heating. In TGA m‐PAIs began to degrade around 440°C and in DSC no phase transitions were detected. In X‐ray diffractometry the m‐PAIs appeared amorphous with loosely developed layered crystalline structure. In liquid crystal (LC)‐aligning performance measured using 4‐n‐pentyl‐4′‐cyanobiphenyl (5CB) on thin film surfaces rubbed with standard velvet fibers, the m‐PAIs showed homogeneous LC alignment parallel to the rubbing direction with 2.5–17.5° pretilt angles, depending on the rubbing density and n‐alkyloxy side chain length. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

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     

Synthesis and properties of new poly(amide‐imide)s based on 2,5‐bis(trimellitimido)chlorobenzene

A series of new aromatic poly(amide‐imide)s were synthesized by the triphenyl phosphite‐activated polycondensation of the diimide‐diacid, 2,5‐bis(trimellitimido)chlorobenzene (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 0.76–1.42 dL g⁻¹. The diimide‐diacid monomer (I) was prepared from 2‐chloro‐p‐phenylenediamine with trimellitic anhydride. Most of the resulting polymers showed an amorphous nature 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. Their cast films had tensile strengths ranging from 74 to 95 MPa, elongations at break from 7 to 11%, and initial moduli from 1.38 to 3.25 GPa. The glass transition temperatures of these polymers were in the range of 233°–260°C, and the 10% weight loss temperatures were above 450°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1691–1701, 1999     

Synthesis and characterization of Sm(III)–hyperbranched poly(ester‐amide) complex

A novel Sm(III)–hyperbranched poly(ester‐amide) complex (Sm(III)–HBPEA) was synthesized, and characterized using Fourier transform infrared, ¹³C NMR and fluorescence spectroscopy and thermogravimetric analysis. Under the conditions used, HBPEA chelates to Sm³⁺ ions mainly via oxygen and nitrogen atoms of functional groups on the HBPEA chain. Modes of bonding of carboxyl groups, terminal hydroxyl groups and amide carbonyl structures may play the most important role in the coordination interaction. On excitation with UV light, the complex exhibits characteristic emission of both HBPEA and Sm³⁺. The presence of Sm³⁺ ions slightly accelerates HBPEA decomposition. Copyright © 2010 Society of Chemical Industry     

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     

Optically active poly(ester‐amide)s: synthesis and characterization

The synthesis and characterization of a new series of chiral poly(ester‐amide)s are reported. They were prepared by the simple reaction of diacid chlorides with biphenolic azo chromophores and optically active dihydroxy compound (isosorbide) in dimethyl acetamide at 100 °C. The polymers containing isosorbide units were optically active. The polymers showed T_g between 100 and 190 °C and were stable up to 400 °C. These poly(ester‐amide)s showed a positive solvatochromism in UV–visible absorption spectra. Second harmonic generation activities were measured by the powder method. © 2001 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 characterization of new aromatic poly(amide–imide)s based on 4‐aryl‐2,6‐bis(4‐trimellitimidophenyl) pyridines

New diimide–dicarboxylic acids, ie 4‐phenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis‐(4‐trimellitimidophenyl)pyridine, were synthesized by the condensation reaction of 4‐phenyl‐2,6‐bis(4‐aminophenyl)pyridine and 4‐p‐biphenyl‐2,6‐bis(4‐aminophenyl)pyridine with trimellitic anhydride in glacial acetic acid or dimethylformamide. The monomers were fully characterized by FT‐IR and NMR spectroscopies, and elemental analyses. A series of novel poly(amide–imide)s with inherent viscosities of 0.68–0.87 dl g^?1 was prepared from the two diimide–diacids with various aromatic diamines by direct polycondensation. The poly(amide–imide)s were characterized by FT‐IR and NMR spectroscopies. The λ_max data for the resulting poly(amide–imide)s were in the range of 260–292 nm. These polymers exhibited good solubilities in polar aprotic solvents. The 10 % weight loss temperatures are above 485 °C under a nitrogen atmosphere. Copyright © 2004 Society of Chemical Industry     

New poly(amide imide)s containing bis(4‐trimellitimidophenyl) sulfone and hydantoin moieties in the main chain: Synthesis and properties

Several new poly(amide imide)s were synthesized through the polycondensation reactions of bis(4‐trimellitimidophenyl) sulfone [N,N′‐(4,4′‐diphenylsulfone) bistrimellitimide] with a number of hydantoin derivatives in a medium consisting of thionyl chloride, N‐methyl‐2‐pyrrolidone, and pyridine. The polycondensations produced a series of novel poly(amide imide)s in high yields with inherent viscosities of 0.20–0.46 dL/g. The resulting poly(amide imide)s were characterized with elemental analysis, viscosity measurements, thermogravimetric analysis, derivative thermogravimetry, solubility testing, and Fourier transform infrared spectroscopy. All the polymers were soluble at room temperature in polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, and N‐methyl‐2‐pyrrolidone. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1776–1782, 2005     

Synthesis and characterization of new rigid‐rod and organosoluble poly(amide–imide)s based on 1,4‐bis(trimellitimido)‐2,3,5,6‐tetramethylbenzene

A series of new aromatic poly(amide–imide)s (PAIs) was synthesized by triphenyl phosphite‐activated polycondensation of the diimide–diacid, 1,4‐bis(trimellitimido)‐2,3,5,6‐tetramethylbenzene (I), with various aromatic diamines in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP), pyridine, and calcium chloride. The PAIs had inherent viscosities of 0.82–2.43 dL/g. The diimide–diacid monomer (I) was prepared from 2,3,5,6‐tetramethyl‐p‐phenylenediamine with trimellitic anhydride (TMA). Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including NMP, N,N‐dimethylacetamide (DMAc), and N,N‐dimethylformamide (DMF). Transparent, flexible, and tough films of these polymers could be cast from DMAc solutions. Their cast films had tensile strengths ranging from 80 to 95 MPa, elongation at break from 10 to 45%, and initial modulus from 2.01 to 2.50 GPa. The 10% weight loss temperatures of these polymers were above 510°C in nitrogen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1162–1170, 2000     

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     

Synthesis and characterization of silicon‐containing poly(amide‐amide)s

A modified new aromatic diacid, bis[(4‐carboxyphenyl) 4‐benzamide] dimethylsilane (IV) with preformed amide linkages and a silicon moiety was synthesized and characterized by IR, NMR, mass spectroscopy, and a physical constant. Novel poly(amide‐amide)s were synthesized from IV and aromatic diamines by Yamazaki's direct polyamidation method in N‐methyl pyrrolidinone. The polymers were obtained in excellent yields and showed reduced viscosities in the range of 0.42–6.15 dL/g. They were readily soluble in aprotic polar solvents. These poly(amide‐amide)s showed glass‐transition temperatures of 303–378°C as measured by DSC and showed no weight loss below 377°C in a nitrogen atmosphere. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1610–1617, 2001     

Synthesis of biodegradable amino‐acid‐based poly(ester amide)s and poly(ether ester amide)s with pendant functional groups

A new family of biodegradable amino‐acid‐based poly(ester amide)s (AA–PEAs) and amino‐acid‐based poly(ether ester amide)s (AA–PEEAs) consisting of reactive pendant functional groups (? COOH or ? NH₂) were synthesized from unsaturated AA–PEAs and AA–PEEAs via a thiol–ene reaction in the presence of a radical initiator (2,2′‐azobisisobutyronitrile). The synthetic method was a one‐step reaction with near 100% yields under mild reaction conditions. The resulting functional AA–PEA and AA–PEEA polymers were characterized by Fourier transform infrared spectroscopy, NMR, and differential scanning calorimetry. These new functional AA–PEA and AA–PEEA derivatives had lower glass‐transition temperatures than the original unsaturated AA–PEA and AA–PEEA polymers, and their solubility in some organic solvents also improved. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of novel optically active poly(imide–urethane)s derived from N,N′‐(pyromellitoyl)‐bis‐(L‐leucine) diisocyanate and aromatic diols

N,N′‐(Pyromellitoyl)‐bis‐(L ‐leucine) diacid was reacted with ethyl chloroformate in the presence of triethylamine followed by reaction with activated sodium azide and gave N,N′‐(pyromellitoyl)‐bis‐(L ‐leucine) diacylazide in high yield. This diacylazide was heated in dry benzene and gave the unstable N,N′‐(pyromellitoyl)‐bis‐(L ‐leucine) diisocyanate ( 5 ) in quantitative yield. Thus, diisocyanate 5 was generated in situ and polycondensation reaction of this monomer with several aromatic diols, such as 4,4′‐dihydroxybiphenyl, 1,4‐hydroquinone, bisphenol A, phenolphthalein and 1,4‐dihydroxyanthraquinone, was performed in dry toluene under refluxing in the presence of 1,4‐diazabicyclo[2.2.2]octane (triethylenediamine) as a catalyst. The polymerization reactions proceeded within 48 h, producing a series of optically active poly(imide–urethane)s with good yield and moderate inherent viscosity in the range 0.18–0.28 dl g^?1. All of the above polymers were fully characterized by infrared spectra, elemental analyses and specific rotation. Some structural characterization and physical properties of these optically active poly(imide–urethane)s are reported Copyright © 2003 Society of Chemical Industry     

Main‐chain liquid crystalline poly(ester‐amide)s containing lithocholic acid units

A series of poly(ester‐amide)s based on an ester group containing lithocholic acid derivative [3‐(3‐carboxypropionyl) lithocholic acid] and several aromatic diamines (naphthalene‐1,5‐diamine, 4,4′‐diaminodiphenyl ether, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenylsulfone, benzidine, m‐phenylenediamine, p‐phenylenediamine, and tetraphenylthiophene diamine) was synthesized and characterized by solubility, viscosity, IR, differential scanning calorimetry, thermogravimetric analysis, and optical microscopy. The polymers were soluble in most of the organic solvents and had inherent viscosities in the range of 0.21–0.38 dL/g. All the polymers exhibited a nematic mesophase, but only on shearing. Thermal transitions due to mesophase formation were not seen in the differential scanning calorimetry thermograms. However, the liquid crystalline character of the polymers was observed under an optical microscope. Thermogravimetric analyses revealed the maximum decomposition temperature was 390–435°C for these polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 73–80, 2006     

Synthesis and characterization of aromatic/cycloaliphatic poly(amide‐ imide‐imide)s from bis(4‐amino‐ 3,5‐dimethylphenyl) cycloalkane derivatives

A series of novel aromatic diamines containing cycloaliphatic moieties was synthesized by the reaction of cycloalkanones like cyclohexanone and cycloheptanone with 2,6‐dimethylaniline. The tetrimide diacid was synthesized using the prepared diamine with 3,3′,4,4′‐benzophenonetetracarboxylic acid dianhydride/pyromellitic dianhydride and p‐aminobenzoic acid. The polymers were prepared by treating the tetrimide diacid with different aromatic diamines. The structures of the monomers and polymers were identified using elemental analysis and Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopy. The polymers show excellent solubility. The polymers are amorphous and have high optical transparency. They also show good thermal stability and their T_g value is found to be in the range 268–305 °C. Copyright © 2007 Society of Chemical Industry