Synthesis of poly(amide‐ester)s by microwave methods

The polycondensation of sebacic acids and ω‐amino alcohols by microwave irradiation was studied. The results were compared to those obtained from conventional melt polycondensation of poly(amide‐ester)s. It was found that the reaction proceeded at a much higher rate upon microwave irradiation. A high yield of thermally stable poly(amide‐ester)s was obtained. The microwave‐synthesized compounds were fully characterized by FTIR and ¹H‐NMR spectroscopy, gel permeation chromatography, and a solubility test. The thermal properties of the poly(amide‐ester)s also were investigated. The results showed that the chemical‐physical properties of the polymers were in good agreement with those of polymers obtained by conventional synthesis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1952–1958, 2007     

Novel poly(ester amide)s from glycine and L‐lactic acid by an easy and cost‐effective synthesis

Novel low molecular weight poly(ester amide)s based on glycine and l ‐lactic acid with interest for the biomedical field were successfully prepared by interfacial polymerization, which is an easy and fast polymerization method. Preparation of the α‐amino acid based diamine, the l ‐lactic acid based diacyl chlorides and the poly(ester amide)s was carried out in the absence of catalysts. The structure of the different poly(ester amide)s was confirmed by ¹H NMR and Fourier transform infrared spectroscopies. The thermal behaviour of the synthesized poly(ester amide)s was evaluated by simultaneous thermal analysis, differential scanning calorimetry and dynamic mechanical thermal analysis. It was found that both the incorporation of an l ‐lactic acid oligomeric segment and the change in its central unit have an important influence on the thermal characteristics of the poly(ester amide)s. These novel poly(ester amide)s can be used as building blocks for the preparation of more complex structures. © 2013 Society of Chemical Industry     

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     

Poly(imide‐amide)s and poly(imide‐ester)s obtained from N,N′‐(4,4′‐Me,R‐diphthaloyl)‐bis‐glycine acid dichloride (R = Me,Et): Synthesis,characterization, and thermal studies

Poly(imide‐amide)s (PIAs) and poly(imide‐ester)s (PIEs) containing two Si‐atoms in the repeating unit were synthesized from acid dichlorides and diamines and diphenols, respectively. The acid dichlorides were obtained from the dianhydrides, which reacted first with glycine and then with thionyl chloride. The dianhydrides were obtained from the tetramethyl derivatives, which were oxidized to the tetra acids and then the dianhydrides were obtained with acetic anhydride. PIAs were obtained in N,N‐dimethylacetamide solution at low temperature and the PIEs in a CHCl₃ solution. Monomers and polymers were characterized by IR and 1H, 13C, and 29Si‐NMR spectroscopy and the results were in agreement with the proposed structures. The η_inh values were indicative of low molecular weight species and of oligomeric nature. The glass transition (T_g) and thermal decomposition temperatures (TDT) values of PIAs were higher than those of PIEs due to the presence of the aromatic rings of the diamine. The aliphatic groups bonded to the Si atom of the acid dichloride moiety promoted the decrease of the thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of new poly(amide–imide)s derived from trimellitylimido‐L‐phenylalanine

N‐Trimellitylimido‐L ‐phenylalanine was prepared from the reaction of 1,2,4‐benzenetricarboxylic anhydride with L ‐phenylalanine in N,N‐dimethylformamide solution at refluxing temperature. The direct polycondensation reaction of the monomer imide‐diacid with 4,4′‐diaminodiphenylsulfone, 4,4′‐diaminodiphenylmethane, 1,4‐phenylenediamine, 1,3‐phenylenediamine, 2,4‐diaminotoluene, 4,4′‐diaminodiphenylether and benzidine was carried out in a medium consisting of triphenyl phosphite, N‐methyl‐2‐pyrrolidone, pyridine and calcium chloride. The resulting poly(amide–imide)s, PAIs, having inherent viscosities of 0.21–0.45 dlg^?1 were obtained in high yield. All of the above compounds were fully characterized by IR spectroscopy and elemental analyses. The optical rotation of all PAIs has also been measured. Some structural characterization and physical properties of these new optically active PAIs are reported. © 2001 Society of Chemical Industry     

Interfacial Polymerization of Linear Aromatic Poly(ester amide)s

Linear aromatic poly(ester amide)s (PEAs) have been synthesized by interfacial polycondensation (IPC) of aromatic diamidoacid chloride: 2-{[4-({[2-(chlorocarbonyl) phenyl]amino} carbonyl) benzoyl]amino} benzoyl chloride (2CCBC), with ethylene glycol, bisphenol A, resorcinol, 4,4′-bis(4-hydroxybenzilidine)diaminobenzanilide and 4,4′-bis(4-hydroxy benzilidine)-m-phenylenediamine in chloroform/water system employing phase-transfer-catalyst. The aromatic diamidoacid chloride has been prepared by condensation of terephthaloyl chloride with anthranilic acid. These polymers were characterized by elemental analysis, FTIR, ¹H-NMR, solubility studies, intrinsic viscosity and TGA analysis. The polyester-amides so obtained show good thermal stability.     

Poly(silyl ester)s: A new route of synthesis via the condensation of Di‐tert‐butyl ester of dicarboxylic acid with dichlorosilane

Poly(silyl ester)s were synthesized by a new route via the condensation of di‐tert‐butyl ester of dicarboxylic acid with dichlorosilane by the elimination of tert‐butyl chloride as a driving force. Three new poly(silyl ester)s with molecular weights typically ranging from 2000 to 5000 amu were produced by the condensation of di‐tert‐butyl adipate with 1,5‐dichloro‐1,1,5,5‐tetramethyl‐3,3‐diphenyl trisiloxane and di‐tert‐butyl fumarate with 1,5‐dichloro‐1,1,5,5‐tetramethyl‐3,3‐diphenyl trisiloxane or 1,3‐dichlorotetramethyl disiloxane. Each polymer was characterized with infrared, ¹H‐NMR, and ¹³C‐NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. This new approach showed several advantages. First, it did not require a catalyst or solvent. Second, the tert‐butyl chloride byproduct was volatile and was easily eliminated. Third, there was no reaction between the growing poly(silyl ester)s and the condensation byproduct, tert‐butyl chloride. Fourth, the monomers could be readily purified. Finally, the polymerization could be performed at relatively low temperatures and in a short time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1378–1384, 2006     

Electrospinning of Novel Poly(ester amide)s

Novel PEAs derived from 1,4‐butanediol, dimethyl adipate and a preformed α,ω‐amino alcohol were synthesised and successfully electrospun from solution. The effects of increasing the ratio of amide/ester groups in the copolymer, polymer concentration, solvent mixtures and applied voltage on fibre morphology and diameter were investigated. The obtained fibres (diameter 180–450 nm) were randomly oriented. The fibre quality and homogeneity increased with increasing amide concentration. The solvent mixture CHCl₃/HCOOH gave the best electrospinning results. The ultra‐fine fibres were characterised using SEM, DSC and FT‐IR, showing that the electrospun fibres are amorphous as compared to the pristine samples. These fibres are potential candidates for use as scaffolds in tissue engineering.

     

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     

超支化聚酰胺酯对聚乳酸增韧改性的研究

采用熔融共混的方法,用生物可降解的超支化聚酰胺酯(HBP)对聚乳酸(PLA)进行增韧改性,制备出具有良好韧性的PLA复合材料。对不同HBP含量的共混物的红外光谱、热性能和力学性能进行了测试和分析。红外光谱显示PLA和HBP间存在氢键作用。HBP的加入使PLA的结晶度从30.99%降低到18.58%。当HBP含量增加到10%时,PLA共混物的拉伸强度略有提高,且断裂伸长达到43.06%。结果表明:HBP的加入对PLA起到了很好的增韧作用。     

Poly(ester amide)s derived from tartaric and succinic acids: Changes in structure and properties upon hydrolytic degradation

The changes in structure and properties taking place in a set of tartaric acid‐based polyamides and poly(ester amide)s upon hydrolytic degradation were examined. Poly(hexamethylene 2,3‐di‐O‐methyl‐L ‐tartaramide)s, either pure or containing minor amounts of succinate ester groups (≤10%), were exposed to humidity or incubated in buffered water at pH 7.4 and 37°C, and their thermal and mechanical properties were evaluated as a function of time. Both moisture uptake and hydrolysis induced a noticeable decay in the tensile properties of polymers. These effects were greatly enhanced by the presence of ester groups, whereas no large differences were noticed for changes in the enantiomeric composition. Variations in the glass transition temperatures and melting points appeared to be slight, whereas crystallinity clearly increased with incubation time. The latter effect was most apparent in poly(ester amide)s with a nearly racemic composition, in which a crystal‐to‐crystal transition was observed to take place upon degradation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 486–494, 2000     

Poly(ester amide)s derived from 1,4-butanediol, adipic acid and 6-aminohexanoic acid. Part II: composition changes and fillers

BAK poly(ester amide)s differing in the amide/ester ratio have been synthesized and characterized, considering spectroscopic data and both thermal and mechanical properties. Degradability under different media (water at 70 °C, acid or enzymatic catalysis at 37 °C) has also been studied by evaluating the changes in intrinsic viscosity, in the NMR spectra and in the surface texture of samples. The use of chain extenders, such as hexamethylene diisocyanate and 1,3-butadiene diepoxide, has been investigated and the optimal reaction conditions are reported here. Changes on mechanical properties due to the incorporation of biodegradable reinforces have also been evaluated. Finally, the synthesis and determination of thermal properties of related poly(ester amide)s constituted by glutaric or succinic acid instead of adipic acid have been investigated.     

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     

Comparative studies on the degradability of poly(ester amide)s derived from L‐ and L,D‐alanine

The hydrolytic degradation of two poly(ester amide)s derived from sebacic acid, dodecanediol, and alanine in both the quiral L configuration and the racemic L ,D mixture has been studied. The degradation was monitored by following the changes in intrinsic viscosity, mass loss, chemical constitution, and mechanical properties. The results show that these poly(ester amide)s degrade slowly at 37°C through the ester linkage. Little changes in the Young's modulus of both samples were found at the beginning of the degradation process. Biodegradation has also been studied by using different enzymes. Papain was the most effective one, although the degradation rate was dependent on the stereochemical composition of the polymer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2312–2320, 1999     

Microwave‐assisted synthesis of new optically active poly(ester‐imide)s containing N,N′‐(pyromellitoyl)‐bis‐L‐phenylalanine moieties

Pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) (1) was reacted with L‐phenylalanine (2) in a mixture of acetic acid and pyridine (3 : 2) and the resulting imide‐acid [N,N′‐(pyromellitoyl)‐bis‐L‐phenylalanine diacid] (4) was obtained in quantitative yield. The compound (4) was converted to the N,N′‐(pyromellitoyl)‐bis‐L‐phenylalanine diacid chloride (5) by reaction with thionyl chloride. A new facile and rapid polycondensation reaction of this diacid chloride (5) with several aromatic diols such as phenol phthalein (6a), bisphenol‐A (6b), 4,4′‐hydroquinone (6c), 1,8‐dihydroxyanthraquinone (6d), 4,4‐dihydroxy biphenyl (6e), and 2,4‐dihydroxyacetophenone (6f) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions proceeded rapidly and are completed within 20 min, producing a series of optically active poly(ester‐imide)s with good yield and moderate inherent viscosity of 0.10–0.26 dL/g. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(ester‐imide)s are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2211–2216, 2002     

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     

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 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     

New generation of thermally stable and conducting poly(azomethine‐ester)s: nano‐blend formation with polyaniline

A new dihydroxy monomer, (E)‐1‐(4‐(4‐(4‐hydroxybenzylidene)thiocarbamoylaminobenzyl)phenyl)‐3‐(4‐hydroxybenzylidene)thiourea, was synthesized and polymerized with thiophene‐2,5‐dicarbonyl/terephthaloyl chloride. The structural characterization of the resulting polymers was carried out using spectral techniques (Fourier transform infrared and ¹H NMR) along with a physical property investigation. Novel polyesters are readily soluble in various amide solvents and possess high molar mass of 112 × 10³–133 × 10³ g mol^?1. The thermal stability was determined via 10% weight loss to be in the range 519–523 °C and the glass transition temperature was 286–289 °C. Electrically conducting poly(azomethine‐ester)‐blend‐polyaniline blends were prepared using mash‐blending and melt‐blending techniques. Materials obtained using the conventional melt‐blending approach generated an efficient conductive network compared with those produced by mash blending. Field emission scanning electron microscopy revealed a nano‐blend morphology for the melt‐blended system owing to increased physical interactions (hydrogen bonding and π–π stacking) between the two constituent polymers. Miscible blends of thiophene‐based poly(azomethine‐ester)‐blend‐polyaniline had superior conductivity (1.6–2.5 S cm^?1) and thermal stability (T₁₀ = 507 °C) even at low polyaniline concentration relative to reported thiophene/azomethine/polyaniline‐based structures. The new thermally stable and conducting nano‐blends could be candidates for various applications including optoelectronic devices. © 2012 Society of Chemical Industry     

Novel optically active poly(amide‐imide)s with tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine moieties by microwave‐assisted polycondensation

Rapid and highly efficient synthesis of novel poly(amide‐imide)s (PAIs) were achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of 4,4′‐carbonyl‐bis(phthaloyl‐L ‐alanine) diacid chloride [N,N′‐(4,4′‐carbonyldiphthaloyl)] bisalanine diacid chloride (1) with six different derivatives of tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine compounds (2a–2f) in the presence of a small amount of a nonpolar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly and was almost completed within 10 min, giving a series of PAIs with inherent viscosities of about 0.25–0.45 dL/g. The resulting PAIs were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of Fourier transform infrared spectroscopy, elemental analyses, inherent viscosity (η_inh), solubility test, and specific rotation. Thermal properties of the PAIs were investigated using thermogravimetric analysis. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2416–2421, 2001