Bismaleimides,bisnadimides, and polyaspartimides containing ether and ester linkages and pyridine

A series of bismaleimides (BMI) and bisnadimides (BNI) containing pyridine ring and flexible linkages were prepared and the structural characterization of the resins was carried out by elemental analysis, FTIR, ¹H NMR, and ¹³C NMR spectroscopy. Their curing behavior were characterized by differential scanning calorimetry and thermal stability of the cured resins were investigated by thermogravimetric analysis. In addition, a series of polyaspartimides were prepared by the polyaddition of the bismalemide with various dimaines. The polymers were characterized by FT‐IR, inherent viscosity, and molecular weight measurements. All the polyimides were soluble in many organic solvents, the glass transition temperature of the polyaspartimides are in the range of 194–231°C, 10% weight loss (T₁₀) takes place in the temperature range of 379–482°C in N₂ and char yield in the range of 44.31–53.31%. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and Characterization of Polyaspartimides Containing Anisyl Moiety

New class of aromatic bismaleimides containing anisyl group were synthesized from bis(4-amino 3,5-dimethyl phenyl) anisyl methane and maleic anhydride via bismaleamic acid as an intermediate followed by cyclodehydration to bismaleimides. The structure was confirmed by FTIR, ¹H-NMR and elemental analysis. Further, a series of polyaspartimides were synthesized by addition reaction of bismaleimide (BMDA) with various diamines. The polymers were characterized by IR and elemental analysis. The polymers exhibit good solubility in organic solvents such as NMP, DMF and DMSO. They exhibit good thermal stability. T _g of polyaspartimides are in the range of 125–278°C and T _10% weight loss are in the range of 398–476°C.     

Studies of phosphonate‐containing bismaleimide resins. I. Synthesis and characteristics of model compounds and polyaspartimides

Two phosphonate‐containing bismaleimide (BMI) [(4,4′‐bismaleimidophenyl)phosphonate] monomers with different melting temperatures and similar curing temperatures were synthesized by reacting N‐hydroxyphenylmaleimide with two kinds of dichloride‐terminated phosphonic monomers. The BMI monomers synthesized were identified with ¹H‐, ¹³C‐, and ³¹P‐nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The phosphonate‐containing BMI monomers react with a free‐radical initiator to prepare phosphonate‐containing BMI polymers and also with various aromatic diamines to prepare a series of polyaspartimides as reactive flame retardants. The polymerization degrees of polyaspartimides depend on the alkalinity and nucleophility of diamines as chain extenders. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) were used to study the thermal properties of the phosphonate‐containing BMI resins such as the melting temperature, curing temperature, glass transition temperature (T_g), and thermal resistance. All the phosphonate‐containing BMI resins, except the BMI polymers, have a T_g in the range of 210–256°C and show 5% weight loss temperatures (T_5%) of 329–434 and 310–388°C in air and nitrogen atmospheres, respectively. The higher heat resistance of cured BMI resin relative to the BMI polymer is due to its higher crosslinking density. Since the recrosslinking reactions of BMI polymers and polyaspartimides occur more easily in an oxidation environment, their thermal stabilities in air are higher than are those in nitrogen gas. In addition, the thermal decomposition properties of polyaspartimides depend on the structures and compositions of both the diamine segments and the BMI segments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1919–1933, 2002     

Synthesis of a bifunctional epoxy monomer containing anthracene moiety and properties of its cured polymer with phenol novolac

A new type of epoxy resin containing anthracene moiety in the backbone was synthesized and was confirmed by elemental analysis, infrared spectroscopy, and ¹H nuclear magnetic resonance spectroscopy. Thermal properties of its cured polymer with phenol novolac were examined by thermomechanical, dynamic mechanical, and thermogravimetric analyses. The cured polymer with phenol novolac showed higher glass transition temperature (T_g), lower thermal expansion, lower moisture absorption, and higher anaerobic char yield at 700°C than a cured polymer having a phenylene group in place of anthracene moiety. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 953–959, 1999     

<Emphasis Type="SmallCaps">l</Emphasis>-Aspartic acid incorporated optically active poly(amide-imide)s: synthesis and characterization

N-trimelliticimido-l-aspartic acid (1) was prepared from the reaction of trimellitic anhydride with l-aspartic acid in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The solution polycondensation of the corresponding activated monomer with eight aromatic diamines were carried out in DMAc. The resulting poly(amide-imide)s were obtained in quantitative yields, showed admirable inherent viscosities (0.20–0.36 dl g⁻¹), good optical activity (+7.32o to +15.24o), and were readily soluble in polar aprotic solvents. They start to decompose (T _10%) above 170 °C and display glass-transition temperatures at 120–237 °C. All of the above polymers were fully characterized by UV, FT–IR, and ¹HNMR spectroscopy, elemental analysis, thermogravimetric analyses, DSC, inherent viscosity measurement, and specific rotation.     

Synthesis and characterization of novel polyaspartimides derived from 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl and various diamines

A novel bismaleimide, 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl, containing noncoplanar 2,2′‐dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2′‐dimethyl‐4,4′‐bis(4‐aminophenoxy)biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m‐cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymers were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X‐ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g⁻¹ in concentration of 1.0 g dL⁻¹ of N,N‐dimethylformamide. All polymers are soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethylsulfoxide, pyridine, m‐cresol, and tetrahydrofuran. The polymers, except PASI‐4, had moderate glass transition temperature in the range of 188°–226°C and good thermo‐oxidative stability, losing 10% mass in the range of 375°–426°C in air and 357°–415°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 279–286, 1999     

Synthesis and properties of bismaleimide resins containing ether bonds

New bismaleimides containing ether bonds were prepared. The thermal properties of the bismaleimides were investigated by differential scanning calorimetry (DSC). The effects of structure of the bismaleimides and curing conditions on the thermal and mechanical properties of the cured resins such as initial decomposition temperature (T_d), glass transition temperature (T_g), and flexural strength were studied. The introduction of ether bonds to bismaleimide resins decreased the brittleness of the resins without reductions in their heat-resistant properties.     

Synthesis and thermal behavior of some brominated bismaleimides and polyaspartimides

Brominated bismaleimides were synthesized by the reaction of brominated bisphenols with 3‐ or 4‐maleimidobenzoyl chloride. The reaction of these maleimides with various aromatic diamines yielded brominated polyaspartimides. The monomers and polymers were characterized by Fourier transformed infrared and proton nuclear magnetic resonance spectroscopy. Thermal behavior of these brominated polyaspartimides was studied and compared with that of related polyaspartimides having other substituents instead of bromine or other bridges in the bisphenolic segment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Poly(aryl imino sulfone)s as new high-performance engineering plastics

Abstract  

Poly(aryl imino sulfone)s (PAISs) as novel high-performance polymers have been obtained by the condensation polymerization of 4,4′-dibromodiphenyl sulfone with different primary aromatic diamines via Palladium-catalyzed aryl amination reaction. The influence of the halogen-containing monomers, solvent, concentration, and temperature on the polycondensation reaction was investigated. The structure of polymers synthesized was characterized by means of FT–IR, NMR spectroscopy, and elemental analysis, the results showed an agreement with the proposed structure. Differential scanning calorimetry and thermal analysis measurements showed that polymers possessed high glass transition temperature (T _g > 145 °C) and good thermal stability with high decomposition temperatures (T _D > 450 °C). These novel polymers also exhibited good mechanical behaviors and good solubility.     

Synthesis and characterization of heterocyclic core-based polybenzoxazine matrices

In the present work, four types of heterocyclic core-based polybenzoxazine matrices (HC-PBZ) developed based on pyridine, thiophene, and thiazole and their molecular structure, thermal, flame-retardant and luminescent properties were studied and discussed. The heterocyclic core-based benzoxazine monomers (HC-BZ) were synthesized using two types of phenols (phenol, and 4-hydroxyphenylacetonitrile), and two types of heterocyclic diamines [2,6-Bis-(4-aminophenyl)-4-thiophen-2-yl-pyridine (BATP) and 4-(2-methylthiazol-5-yl)-2,6-bis-(4-aminophenyl)-pyridine (BAMTP)] with formaldehyde through Mannich reaction. The structure of the four HC-BZ monomers was confirmed by various spectral analysis such as Fourier-transform infrared spectroscopy (FTIR), and Nuclear magnetic resonance spectroscopy (¹HNMR and ¹³CNMR). All the four HC-BZ monomers have the maximum range of curing temperature (T _p) between 252 and 267 °C. Data resulted from the thermal studies indicate that the HC-PBZ exhibits better T _g, thermal stability and flame-retardant properties. Among the four HC-PBZ systems the thiazole based system possesses the higher value of T _g of 268 °C and thermal stability when compared to those of other matrices. It was also observed that the HC-BZ monomers and HC-PBZ polymers exhibit a photoluminescent (PL) emission range between 441–445 and 414–417 nm, respectively. Overall, it seems that the thiazole and thiophene based HC-PBZ can be considered as competitive materials for luminescent applications with high thermal and flame-retardant properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47134.     

Conjugated opto/electroactive ethynylene-carbazole polymers with TTF as pendant group

Three conjugated ethynylene-carbazole polymers with Tetrathiafulvalene (TTF) as pendant group (P1–P3) were synthesized by using sonogashira coupling reaction and characterized by ¹H NMR, GPC, CV, UV–Vis, FL, and TGA. CV and UV–Vis spectra showed that an intramoleular interaction existed between the electron-rich moiety TTF and electron-deficient moiety polyethynylcarbazole of the polymers. A strong fluorescence quench (ca. 99%) could be observed, compared to the polyethynylene-carbazole without TTF units, which could be ascribed to the photo-induced electron transfer (PET) interaction from TTF moiety to the polyethynylene-carbazole backbone. The observed onset decomposition temperatures (T _d) for P1–P3 varied from 256 to 298 °C. The polymers mentioned above exhibited good thermal properties and higher conductivity (neutral conductivity ~7–11 × 10⁻⁷ S cm⁻¹; doped conductivity ~6–11 × 10⁻⁴ S cm⁻¹).     

Synthesis and characterization of new organosoluble polyaspartimides containing phosphorus

Novel polyaspartimides were successfully synthesized via Michael addition reactions involving phosphorus-containing diamines and bismaleimides as monomers and using p-toluenesulfonic acid and N-N-dimethylacetamide as a catalyst and a solvent, respectively. The yields of the polymerization and the molecular weights and inherent viscosities of the polymers increased with the increasing monomers' concentrations, with an upper limit of 0.92 mol/l. All of the obtained polymers were soluble in organic solvents and showed high glass transition temperatures of 227-256 °C, good thermal stability of 360-427 °C, high char yields of 53-64% in nitrogen and 25-46% in air at 700 °C.     

Synthesis and characterization of poly (amide-imide-imide)s based on diacids with bulky m-chloro phenyl moiety and rigid pyridine moiety

A series of novel aromatic diamines containing kinked m-chloro phenyl moiety was synthesized by the reaction of m-chloro benzaldehyde with 2,6-dimethyl aniline. The tetraimide diacid was synthesized by using the prepared diamine with benzophenone tetracarboxylic acid dianhydride (BPTDA) and p-amino benzoic acid. The polymers were prepared by treating the tetraimide diacid with different aromatic diamines. The structures of the monomers and polymers were identified by ¹H-NMR, FTIR,¹³C-NMR and elemental analysis. The polymers showed excellent thermal stability, solubility and mechanical properties. Their structure–property relationship was studied by comparing these m-chloro polymers with polymers containing rigid Pyridine moiety.     

Synthesis and characterization of novel polyimides starting from 1,2‐bis(p‐dimethylaminobenzylideneimino)alkane homologues and various dianhydrides

The objective of this research was the preparation of polyimides from 1,2‐bis(p‐dimethylaminophenylimino)alkane homologues and various dianhydrides in N‐methylpyrrolidone by one‐stage polycondensation. The monomers were prepared via condensation of p‐dimethylaminobenzaldehyde and the corresponding diamines, 1,4‐diaminobutane, 1,3‐diaminopropane and 1,2‐diaminoethane. The influence of the incorporation of this moiety into the polymer backbone on the properties of the polyimides has been evaluated. The thermogram of the polyimides indicated that PI‐10 to PI‐32 had T_g values ranging from 181 to 290 °C. The inherent viscosities of the polymers ranged from 0.99 to 2.05 dl g^?1, and the highest solubility was obtained without significant loss of the thermal properties. Copyright © 2004 Society of Chemical Industry     

Synthesis and evaluation of the thermal properties of biosourced poly(ether)ureas and copoly(ether)ureas from 1,4:3,6‐dianhydrohexitols

A new series of poly(ether)ureas were prepared by solution polyaddition of three diamines based on 1,4:3,6‐dianhydrohexitols with three types of diisocyanate. The corresponding poly(ether)ureas were obtained with high yields. They were characterized by various analytical techniques (NMR, TGA and differential thermal analysis, DSC). NMR spectroscopy allowed us to confirm structure type and to optimize reaction conditions and DSC proved the high thermal properties of the products obtained (T_g and T_m in the range 126 ? 158 °C and 235 ? 330 °C respectively). Then, copoly(ether)ureas partially based on commercial diamines were synthesized in order to reduce polymer cost and tune their thermal behaviour. The reactivity of both diamines was evaluated by their incorporation in the polymer by means of NMR spectra. Then their thermal properties were compared with fully commercial diamine based polyureas by DSC studies. © 2014 Society of Chemical Industry     

Synthesis and properties of polyimides based on isomeric (4, 4′-methylenediphenoxyl) bis (phthalic anhydride)s (BPFDAs)

Isomeric (4, 4′-methylenediphenoxyl) bis (phthalic anhydride)s (BPFDAs)were synthesized and their structures were determined via IR spectra and ¹H NMR. Polyimides were then prepared from isomeric BPFDAs and aromatic diamines in N, N-Dimethylacetamide (DMAc) via the conventional two-step method. Polyimides based on 3, 3′-BPFDA are soluble in common organic solvents at room temperature, while polyimides based on 4, 4′-BPFDA were only partially soluble in high-boiling-point solvent even upon heating. The 5% weight-loss temperatures (T _5% ) of these polyimides were in the range of 430–500 °C in air. Dynamic mechanical thermal analysis (DMTA) indicated that the glass-transition temperatures of polyimides from 3, 3′-BPFDA are around 10–20 °C higher than those of polyimides from 4, 4′-BPFDA. The wide-angle X-ray diffraction showed that all polyimides are amorphous.     

Synthesis and Characterization of processable heat resistant poly (amide-imides) for high temperature applications

Summary A series of new polyamide-imides with high thermal stability were synthesized by direct polycondensation of imide containing diamines with various aromatic diacids using polar aprotic solvents. In this technique triphenylphosphite (TPP) and pyridine were used as condensing agents to form polyamide-imide through N-phosphonium salts of pyridine. The various imide containing diamines were prepared by reacting dianhydride (PMDA, BPTDA) with aromatic diamines such as phenylene diamine, 3,3’-dichloro 4,4’-diaminodiphenylmethane and 2,6-diaminopyridine in 1:2 ratio. The diacids containing flexible ether units were prepared by treating diol with aromatic acid (2,4-dichlorobenzoic acid). The polyamide-imides obtained by this technique were characterized by elemental analysis, FTIR and ¹H-NMR. The solubility of these polyamide-imides was found to be good in polar aprotic solvents such as NMP, DMF, and DMAc etc. The viscosity of the polyamide-imides were determined and found to be in the range of 1.21 to 1.76 dl/g indicating the formation of high molecular weight polymers. The thermal stability of the polymers was tested using DSC and the Tg values are in the range of 207–234 °C showing the high thermal stability of the prepared polymers.     

Synthesis and characterization of poly(arylene ether) containing cyanate ester networks

A series of bisphenols containing ether linkage were prepared from halo phenol/dihalo compound and dihydroxy compounds in the presence of K₂CO₃. The bisphenols were transformed to cyanate esters by treatment with cyanogen bromide using triethyl amine catalyst. The structure of all the five bisphenols and the cyanate esters were structurally confirmed by FT-IR, ¹H-NMR and ¹³C-NMR spectral methods and elemental analysis. The cyanate esters were cured at 100 °C (30 min) → 150 °C (30 min) → 200 °C (60 min) → 250 °C (3 hr). The thermal properties of the cured resins were studied by DSC and TGA. DSC analysis shows that these cyanate esters exhibit T _g in the range of 203–234 °C. The CE(c) has the highest glass transition temperature. The cyanate ester CE(e) shows the lowest T _g which is due to its asymmetric structure. The initial degradation temperature of the cured resins was found to be in the range of 324–336 °C. The Limiting Oxygen Index (LOI) value, determined by Van Krevelen’s equation, is in the range of 35.5–38.7.     

Synthesis and characterization of polyarylureas. I. Potentially semiconducting polymers

Polyarylureas were synthesized from the reaction between phosgene with aromatic diamines. Depending on the pH, the polyarylureas presented different colors when the solvent used was pyridine. The polyarylureas were characterized by IR spectroscopy, elemental analysis, and X‐ray photoelectron spectroscopy (XPS). To study the thermal stability of the polymers, a thermal degradation was performed between 35 and 700°C. The polyarylureas decomposed above 350°C. Without doping, polyarylureas are considered as semiconductors [σ = 10^?9 (Ωcm)^{? 1}]; after doping with I₂, their electrical conductivity increases by several orders of magnitude. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 822–830, 2001     

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