Chemoselective synthesis of polyamides containing hydroxyl and amino substituents by direct polycondensation

A convenient method for the synthesis of polyamides containing hydroxyl and amino substituents on the aromatic rings of the backbones was developed. These polymers were prepared readily by the chemoselective polycondensation of dicarboxylic acids with diamines with hydroxyl and amino functional groups via the activating agent diphenyl(2,3‐dihydro‐2‐thioxo‐3‐bezoxazolyl)phosphonate. The model reactions were studied in detail to demonstrate the feasibility of chemoselective polycondensation. The direct polycondensation of 5‐hydroxy or 5‐aminoisophthalic acid with 4,4′‐diamino‐4″‐hydroxytriphenylmethane proceeded smoothly under mild conditions and produced the desired polyamides with inherent viscosities up to 0.73 dL · g⁻¹. The polymers obtained were characterized by IR, ¹H NMR, and ¹³C NMR spectroscopies. The polymers were readily soluble in aprotic polar solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethyl formamide, and dimethyl sulfoxide. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3875–3882, 2000     

Condensation routes to polyaniline and its analogs

To obtain polyanilines which are more structurally perfect than those obtainable by the oxidation of anilines, polycondensation procedures were investigated. Model reactions gave extensive information about yields and about the physical properties of the putative structural polymer units. Condensation of anthraquinones with aromatic diamines using titanium tetrachloride and the unique base, 1,4‐diazabicyclo‐[2.2.2]‐octane Dabco, gave high molecular weight orange polyquinonimines. Alkoxy groups on the anthraquinone ring aided solubility and molecular weight, and appropriately positioned alkoxy groups afforded stereoregular polymers. A bisthiophene benzoquinone also polymerized successfully. Application of the same procedure to 2,5‐dimethyl‐p‐benzoquinone gave stereoregular poly(arylene benzoquinonimines), close analogs of pernigrani line. The factors causing problems in achieving high yields and high molecular weight were identified. Recent synthetic developments in this field are discussed. Reduction of the obtained polyquinonimines proceeded smoothly to the leucoemeraldine analogs. Unlike the results from pernigraniline obtained by oxidative polymerization, no evidence for the formation of the electrically conductive emeraldine form was obtained. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4751–4763, 2007     

Soluble aromatic poly(ether amide)s containing aryl‐, alkyl‐, and chloro‐substituted phthalazinone segments

A series of novel aromatic diamines ( 2 – 4 ) containing the alkyl‐, aryl, or chloro‐substituted group of phthalazinone segments were synthesized via two synthetic steps starting from 4‐(3‐R‐4‐hydroxyphenyl)‐2,3‐phthalazinone‐1 (R = Ph, CH₃, Cl). Three series of aromatic polyamides containing phthalazinone moieties were prepared through diamines 2 – 4 reacting with different aromatic dicarboxylic acids via a direct Yamazaki–Higashi phosphorylation polycondensation reaction. The resulting aromatic polyamides had inherent viscosities in the range of 0.40–0.76 dL/g. The thermal property of the polyamides was examined with DSC and thermogravimetric analysis. The glass‐transition temperatures of these polyamides ranged from 298 to 340 °C. The 10% mass‐loss temperature was above 405 °C under nitrogen. Structures of monomers 2 – 4 and the polymers were confirmed by Fourier transform infrared spectroscopy, ¹H NMR, and mass spectrometry. Good solubility of these polymers in polar solvents such as N‐methylpyrrolidone, dimethylformamide, dimethylacetamide (DMAc), and m‐cresol was observed, and tough, flexible films were obtained from the polymer's DMAc solutions. The effect of the substituted group on the physical property of polymers was also investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2026–2030, 2004     

Soluble polyimides containing alicyclic structures

A series of novel aromatic diamines containing kinked cycloalkane structures between two phenyl rings were synthesized by HCl-catalyzed condensation reaction of excess aniline and corresponding cycloalkanone derivatives. The structures of the diamines were indentified by ¹H NMR, ¹³C NMR, FT-IR spectroscopy and elemental analysis. The polyimides were synthesized from the obtained diamines with various aromatic dianhydrides by one-step polymerization in m-cresol. The polymerization was conducted for 6∼8 h with refluxing, which was enough to obtain the polymers with high molecular weight. The inherent viscosities of the resulting polyimides were in the range of 0.37∼1.66 dl/g. All polymers were readily soluble in common organic solvents such as chloroform, tetrachloroethane, dimethylacetamide, etc. and the glass transition temperatures were observed at 290 to 372°C. UV-visible spectra were obtained to measure the transparency of polymer films. Most of the polymers showed high transmission above 90 % in the wavelength of 450 ∼ 600 nm.     

Polymerization of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L‐leucine) diacid chloride with aromatic diamines by microwave irradiation

A new facile and rapid polycondensation reaction of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L‐leucine) diacid chloride (1) with several aromatic diamines, including benzidine (2a), 4,4′‐diaminodiphenyl methane (2b), 1,5‐diaminoanthraquinone (2c), 4,4′‐sulfonyldianiline (2d), 3,3′‐diaminobenzophenone (2e), P‐phenylenediamine (2f), 2,6‐diaminopyridine (2g), 4,4′‐diaminobenzophenone (2h), 2,4‐diaminotoluene (2i), and 4,4′‐diaminodiphenylether (2j), was developed with 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 compared to conventional solution polycondensation and finished within 12 min, producing a series of optically active poly(amide‐imide)s with quantitative yields and high inherent viscosities of 0.50–1.93 dL/g. All of the polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(amide‐imide)s are reported. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1154–1160, 2000     

Synthesis of bithiazole‐based crystalline polymers via palladium‐catalyzed direct CH arylation

Palladium‐catalyzed direct arylation polycondensation afforded a bithiazole‐based homopolymer and donor–acceptor (D–A)‐type copolymers where the bithiazole unit served as an acceptor unit. The results of polymerization strongly depended on the solubility of the polymers; long alkyl chain substituents were required for the formation of high‐molecular‐weight polymers in high yields owing to low solubility of the bithiazole‐based polymers. X‐ray diffraction studies revealed that the obtained polymers were highly crystalline. In particular, a well‐ordered lamellar structure was observed in the D–A‐type copolymer with flexible alkyl chains after thermal annealing, presumably owing to the combination of interchain interactions between the bithiazole units and the electrostatic D–A interactions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1396–1402     

Acid chloride‐functionalized hyperbranched polyester for facile and quantitative chain‐end modification: One‐pot synthesis and structure characterization

Carboxylic acid chloride end‐functionalized all‐aromatic hyperbranched polyesters were prepared from the bulk polycondensation of the AB₂ monomer 5‐(trimethylsiloxy)isophthaloyl dichloride. The acid chloride end functionality of the hyperbranched polyester was modified in situ with methanol and yielded methyl ester ends in a one‐pot process. Chain‐end functionalization and esterification were quantitative according to both potentiometric titration and ¹H NMR analysis. The signals of ¹H and ¹³C NMR spectra of the esterified hyperbranched polyester were fully assigned from model compounds of the focal, linear, dendritic, and terminal units. The degree of branching and molecular weight averages measured by ¹H and ¹³C NMR spectroscopy and multidetector size exclusion chromatography increased systematically with increasing polymerization temperatures between 80 and 200 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2855–2867, 2002     

Preparation and properties of novel polyimides derived from 4‐aryl‐2,6 bis(4‐amino phenyl)pyridine

To prepare novel polyimides with enhanced thermal stability and high solubility in common organic solvents, diamine monomers, 4‐aryl‐2,6 bis‐(4‐amino phenyl)pyridine, were introduced. The diamines were reacted with three different conventional aromatic dianhydrides including pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and hexafluoroisopropylidene‐2,2‐bis(phthalic‐dianhydride) (6FDA) in dimethylacetamide solvent to obtain the corresponding polyimides via the polyamic acid precursors and chemical imidization. The monomers and polymers were characterized by Fourier transform infrared spectroscopy, ¹H NMR, mass spectroscopy, and elemental analysis; and the best condition of polymerization and imidization were obtained via the study of model compound. The polyimides showed little or no weight loss by thermogravimetric analysis up to 500 °C, and those derived from 6FDA exhibited good solubility in various polar solvents. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3826–3831, 2001     

Chemical synthesis and characterization of poly(aniline‐co‐ethyl 3‐aminobenzoate) copolymers

Copolymers of aniline and ethyl 3‐aminobenzoate (3EAB) were synthesized by chemical polymerization in several mole ratios of aniline to functionalized aniline, and their physicochemical properties were compared to those of poly(aniline‐co‐3‐aminobenzoic acid) (3ABAPANI) copolymers. The copolymers were characterized with UV–vis, FTIR, Raman, SEM, EPR, and solid‐state NMR spectroscopy, elemental analysis, and conductivity measurements. The influence of the carboxylic acid and ester group ring substituents on the copolymers was investigated. The spectroscopic studies confirmed incorporation of 3ABA or 3EAB units in the copolymers and hence the presence of C?O group in the copolymer chains. The conductivity and EPR signals both decreased with increasing 3EAB content of the copolymers emeraldine salt (ES) form. The conductivity of the ES form of 3ABAPANI was found to be high (1.4 × 10^?1 S cm^?1) compared with the conductivity (10^?2–10^?3 S cm^?1) of 3EABPANI (ES) copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1339–1347, 2010     

Synthesis and characterization of novel,optically active poly(amide‐imide)s from N,N′‐(4,4′‐sulfonediphthaloyl)‐bis‐L‐phenylalanine diacid chloride and aromatic diamines under microwave irradiation

3,3′,4,4′‐Diphenylsulfonetetracarboxylic dianhydride was reacted with L ‐phenylalanine in acetic acid, and the resulting imide acid ( 3 ) was obtained in high yield. The diacid chloride ( 4 ) was obtained from its diacid derivative ( 3 ) by reaction with thionyl chloride. The polycondensation reaction of 4 with several aromatic diamines such as 4,4′‐sulfonyldianiline, 4,4′‐diaminodiphenyl methane, 4,4′‐diaminodiphenylether, p‐phenylenediamine, m‐phenylenediamine, 2,4‐diaminotoluene, and 1,5‐diaminonaphthalene was developed with a domestic microwave oven in the presence of trimethylsilyl chloride and a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed with two other methods: low‐temperature solution polycondensation in the presence of trimethylsilyl chloride and reflux conditions. A series of optically active poly(amide‐imide)s with moderate inherent viscosities of 0.21–0.42 dL/g were obtained in high yield. All of the aforementioned polymers were fully characterized by IR, ¹H NMR elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly(amide‐imide) s are reported. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3974–3988, 2003     

Ring‐opening polymerization of 1,4‐dioxan‐2‐one initiated by lanthanum isopropoxide in bulk

Lanthanum isopropoxide (La(OiPr)₃) has been synthesized and employed for ring‐opening polymerization of 1,4‐dioxan‐2‐one in bulk as a single‐component initiator. The influences of reaction conditions such as initiator concentration, reaction time, and reaction temperature on the polymerization were investigated. The kinetics indicated that the polymerization is first‐order with respect to the monomer concentration. The Mechanistic investigations according to ¹H NMR spectrum analysis demonstrated that the polymerization of PDO proceeded through a coordination‐insertion mechanism with a rupture of the acyl‐oxygen bond of the monomer rather than the alkyl‐oxygen bond cleavage. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5214–5222, 2008     

Sequential conversion of orthogonally functionalized diblock copolymers based on pentafluorophenyl esters

Statistic and block copolymers exhibiting activated ester side groups were synthesized by reversible addition‐fragmentation chain transfer polymerization in the presence of cumyl dithiobenzoate, benzyl dithiobenzoate, and 4‐cyano‐4‐((thiobenzoyl)sulfanyl)pentanoic acid as chain transfer agents. Pentafluorophenyl methacrylate and pentafluorophenyl 4‐vinylbenzoate were used to enable a sequential functionalization of the obtained copolymers by conversion of the activated esters with different amines. ¹H NMR spectroscopy, ¹⁹F NMR spectroscopy, and FTIR spectroscopy showed the successful step‐by‐step conversion of the different activated esters by aniline followed by aliphatic amines, thereby realizing a sequential functionalization of block copolymers with just one specific reactive group. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3683–3692, 2010     

New polyamidation through the activation of amino groups with phenyl dichlorophosphite in pyridine

Polyamidation with phenyl dichlorophosphite (PDCP) as a new condensing agent was studied. A model reaction of benzoic acid and aniline with PDCP through a change in their addition order revealed that PDCP reacted with aniline more favorably than it did with the acid, and it could activate about 2 mol of aniline to produce benzanilide in a nearly quantitative yield. A preferential reaction with aniline occurred even in the presence of the acid. The reaction was applied to the polyamidation of dicarboxylic acids and diamines or of p‐aminobenzoic acid (PABA) with 0.6 equiv of PDCP with respect to the amino groups in pyridine/N‐methyl‐2‐pyrrolidone in the presence of LiCl. Polyterephthalamides and polyisophthalamides with moderate inherent viscosity values were produced. The polycondensation of PABA was significantly promoted by the slow addition of PDCP over a period of 20–40 min and the presence of LiCl, producing poly(p‐benzamide) with inherent viscosity values of about 2.4. Unsubstituted PDCP and PDCPs with an electron‐donating methoxy substituent afforded better results. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4126–4131, 2004     

Hydrogen‐bonded thermotropic liquid‐crystalline polyester–amides from bis(hydroxy alkamido)aranes: Synthesis and properties

Hydrogen‐bonded aromatic–aliphatic polyester–amides (PEAs) were prepared by solution/melt polycondensation of aromatic–aliphatic amidodiols 1,4‐bis(4‐hydroxybutyramide)benzene (BHBB), 1,4‐bis(5‐hydroxy pentamide)benzene, 1,4‐bis(6‐hydroxyhexamide)benzene, 1,4‐bis(4‐hydroxybutyramidexylene), 1,4‐bis(5‐hydroxypentamidexylene, 1,4‐bis(4‐hydroxybutyramide)benzene, and 1,4‐bis(6‐hydroxyhexamidexylene) with terephthaloyl chloride/dimethyl terephthalate. Aromatic–aliphatic amido diols were prepared by the aminolysis of γ‐butyrolactone, δ‐valerolactone, and ?‐caprolactone with aromatic diamines such as paraphenylene diamine and paraxylene diamine. The monomers and polymers were characterized by chemical analysis (hydroxyl value and elemental analysis), Fourier transform infrared spectroscopy, ¹H NMR, and ¹³C NMR. The thermal‐ and phase‐transition behaviors of the polymers were investigated by differential scanning calorimetry in combination with hot‐stage optical microscopy. Crystallinity of polymers was examined with wide‐angle X‐ray diffraction. The polymers exhibited liquid crystallinity with layered structures formed by self‐organization of the hetero intermolecular hydrogen‐bonded networks indicating smectic phases except for PEAs prepared from BHBB. The hydrogen atom of the phenyl‐substituent group forces the neighboring carbonyl groups out of plane of the rings preventing formation of layered structures in the case of BHBB. The PEAs retained intermolecular hydrogen bonding even in the mesomorphic state, and variations in the hydrogen‐bonded lamellae/micelles might be responsible for the variations from one smectic to another texture. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 335–346, 2003     

The effect of amide solvent structure on the direct arylation polymerization (DArP) of 2‐Bromo‐3‐hexylthiophene

In this work, we investigate the influence of the amide solvent chemical structure on the properties of poly(3‐hexylthiophene) (P3HT) prepared via direct arylation polymerization (DArP). Our findings indicate that for successful polymerization the amide must possess an acyclic aliphatic structure since cyclization of an amide results in a complete shutdown of DArP reactivity as evidenced by failed polymerization in N‐methylpyrrolidone, whereas the presence of an aromatic motif renders the amide solvent susceptible to C? H activation and leads to incorporation of the solvent structure into the P3HT backbone, as demonstrated on the example of N,N‐diethylbenzamide. Additionally, we observed that the steric bulk of alkyl substituents on both the nitrogen atom and the carbonyl group within the amide structure has to be delicately balanced for optimal DArP reactivity. In the optimal cases, P3HT is obtained in high yield, with high molecular weight and contains a minimal amount of structural defects. The obtained polymer samples were comprehensively studied in terms of their chemical structure, optical, thermal and solid‐state properties in thin films using GPC analysis, ¹H NMR, MALDI, UV–vis, GIXRD spectroscopy, and DSC. We additionally note a drastic difference of the amide solvent effect between DArP and Stille polymerization. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2494–2500     

Vinylic and ring‐opening metathesis polymerization of norbornene with bis(β‐ketoamine) cobalt complexes

Cobalt complexes 1 – 4 bearing N,O‐chelate ligands based on condensation products of 1‐phenyl‐3‐methyl‐4‐benzoyl‐5‐pyrazolone with aniline, o‐methylaniline, α‐naphthylamine, and p‐nitroaniline, respectively, were synthesized, and the structures of 1 and 4 were characterized by single‐crystal X‐ray diffraction analyses. The bis(β‐ketoamine) cobalt complexes could act as moderately active catalyst precursors for norbornene polymerization with the activation of methylaluminoxane. This catalytic reaction proceeded mainly through a vinyl‐type polymerization mechanism. ¹H NMR and IR showed that in all cases, a small amount of double bonds raised from ring‐opening metathesis polymerization (ROMP) was present in the polymerization products. The variation of the polymerization conditions affected the ROMP unit ratio in the polynorbornenes. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5535–5544, 2005     

Substituent effect on azobenzene‐based liquid‐crystalline organophosphorus polymers

An Erratum has been published for this article in Journal of Polymer Science Part A: Polymer Chemistry (2003) 41(23) 3862 A new series of combined‐type, azobenzene‐based organophosphorus liquid‐crystalline polymers were synthesized, and their photoisomerization properties were studied. The prepared polymers contained azobenzene units as both the main‐chain and side‐chain mesogens. Various groups were substituted in the terminal of the side‐chain azobenzene mesogen, and the effects of the substituents were investigated. All the polymers were prepared at the ambient temperature by solution polycondensation with various 4‐substituted phenylazo‐4′‐phenyloxyhexylphosphorodichloridates and 4,4′‐bis(6‐hydroxyhexyloxy) azobenzene. The polymers were characterized with gel permeation chromatography, Fourier transform infrared, and ¹H, ¹³C, and ³¹P NMR spectroscopy. Thermogravimetric analysis revealed that all the polymers had high char yields. The liquid‐crystalline behavior of the polymers was examined with hot‐stage optical polarizing microscopy, and all the polymers showed liquid‐crystalline properties. The formation of a mesophase was confirmed by differential scanning calorimetry (DSC). The DSC data suggested that mesophase stability was better for electron‐withdrawing substituents than for halogens and unsubstituted ones. Ultraviolet irradiation studies indicated that the time taken for the completion of photoisomerization depended on the dipolar moment, size, and donor–acceptor characteristics of the terminal substituents. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3188–3196, 2003     

A convenient room temperature polycondensation toward hyperbranched AB2‐type all‐aromatic polyesters with phenol terminal groups

As a convenient alternative to the classical melt polycondensation the one‐pot solution polycondensation of suitable AB₂ monomers under mild conditions has been successfully adapted to hyperbranched all‐aromatic polyester with phenol terminal groups. The polymerization was performed in solution at room temperature directly using commercially available 3,5‐dihydroxybenzoic acid as monomer and 4‐(dimethylamino) pyridinium 4‐tosylate as catalyst to suppress the formation of N‐acylurea. Different carbodiimides as coupling agents were investigated to find the optimal esterification conditions. The polymers have been characterized extensively and were compared with their well‐known analogs synthesized in melt. The characterization was carried out by NMR spectroscopy, size exclusion chromatography, and asymmetric flow‐field flow fractionation as an alternative separation technique for multifunctional polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5158–5168, 2009     

Addition of five‐membered cyclic carbonate with amine and its application to polymer synthesis

A bifunctional five‐membered cyclic carbonate was synthesized from carbon dioxide and diglycidyl terephthalate, and its polyaddition with alkyl diamines were carried out in DMF at room temperature to obtain the corresponding poly(hydroxyurethane)s with M_n s in the range of 6300–13200 in good yields. The structures of the obtained polymers were confirmed by IR and NMR spectroscopy and their glass‐transition and decomposition temperatures were observed at 3–29 °C and 182–277 °C, respectively. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2375–2380, 2000     

Synthesis of highly refractive and transparent polyimides derived from 4,4′‐thiobis[2″,6″‐dimethyl‐4″‐(p‐phenylenesulfanyl)aniline]

New sulfur‐containing aromatic diamines with methyl groups at the ortho position of amino groups have been developed to prepare highly refractive and transparent aromatic polyimides (PIs) in the visible region. All aromatic PIs derived from 4,4′‐thiobis[2″‐methyl‐4″‐(p‐phenylenesulfanyl)aniline ( 2 ), 4,4′‐thiobis[2,″6″‐dimethyl‐4″‐(p‐phenylenesulfanyl)aniline ( 5 ), and aromatic dianhydride, 4,4′‐[p‐thiobis(phenylenesulfanyl)]diphthalic anhydride ( 6 ) were prepared via a two‐step polycondensation. All PIs showed good thermal properties, such as 10% weight loss temperature in the range of 497–500 °C and glass transition temperatures above 196 °C. In addition, the PIs showed good optical properties, such as optical transparency above 75% at 450 nm with a 10‐μm film thickness, high refractive indices ranging from 1.7135 to 1.7301, and small in‐plane/out‐of‐plane birefringences between 0.0066 and 0.0076. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 656–662, 2010