N-(2-biphenylenyl)-4-[2′-phenylethynyl]phthalimide—new monomer synthesis, cure and thermal properties of resulting high temperature polymer (original) (raw)
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Polymer International, 2004
A detailed study is presented of the high-temperature cure of the difunctional monomer N-(2-biphenylenyl)-4-[2′-phenylethynyl]phthalimide (BPP) and the thermal properties of the resulting homopolymer. Although the phenylethynyl groups are consumed within 1 h at 370 °C, other reactions continue well after this, leading to a cured polymer whose glass transition temperature (Tg) is highly dependent on cure time and temperature. A Tg of 450 °C is achieved after a 16 h cure at 400 °C. Use of chemometrics to analyse the infrared spectra of curing BPP provides evidence for changes in the aromatic moieties during cure, perhaps indicative of co-reaction between the biphenylene and phenylethynyl groups; however, other processes also contribute to the overall complex cure mechanism. Despite the high Tg values, BPP homopolymer exhibits unacceptably poor thermo-oxidative stability at 370 °C, showing a weight loss of about 50 % after 100 h ageing. This is perhaps a result of formation of degradatively unstable crosslink structures during elevated-temperature cure. Copyright © 2004 Society of Chemical Industry
Journal of Applied Polymer Science, 2018
This paper describes the synthesis and characterization of a bisphthalonitrile monomer having an imide linkage prepared by reacting 4,4 0-(hexafluoroisopropylidene) diphthalic anhydride with 4-(4-aminophenoxy) phthalonitrile. The structure of the monomer was confirmed by Fourier transform infrared, 1 H-NMR, and 13 C-NMR spectroscopy. The curing behavior of bisphthalonitrile monomer was investigated in the absence or presence of different diamines using differential scanning calorimetry. Diamines 4,4 0diaminodiphenyl ether (DDE) and 4,4 0-diaminodiphenylsulfone (DDS) were used to investigate the effect of the structure of diamines on the curing behavior of bisphthalonitrile monomer. An exothermic transition due to curing was observed in the DSC scan, and the curing temperature was found to be dependent on the nucleophilicity of the amine. DDE was found to be more reactive than DDS. The thermal stability of the cured resins was evaluated using thermogravimetry in nitrogen atmosphere. All of the cured samples were stable up to 400 8C and leave behind 62% char residue at 800 8C, which was found to be dependent on the structure of the diamine used for curing as well as on the curing conditions.
Thermochimica Acta, 2020
Due to their outstanding properties, phthalonitrile based polymers plays an important role in high performance advanced materials evaluated depending upon their curing process and mechanism. Henceforth it is necessary to understand the curing kinetics of bisphthalonitrile monomer having imide linkage using 4, 4'-diaminodiphenylsulfone (DDS) as curing agent for further investigations. Thus, curing kinetics was investigated by recording non-isothermal differential scanning calorimetric (DSC) scans at heating rates of 5 °C, 10 °C, 15 °C and 20 °C/ min. Activation energy for bisphthalonitrile/4, 4'-diaminodiphenylsulfone (DDS) system was calculated using Starink method and results give a substantial evidence that Arrhenius activation energy (E a) are certainly dependent on the structure of monomer and curing agent. The cured FIPN/DDS, ODPA-PN/ DDS systems show comparable high thermal stability and elevated glass transition temperature as compared to Bis-ADPN/ DDS composition. Subsequently, this composition exhibits comparative heat resistance and improved moisture resistance.
Polyimides derived from 1,4-bis [3-oxy-( N -aminophthalimide)] benzene
Journal of Applied Polymer Science, 2009
A novel diamine, 1,4-bis [3-oxy-(N-aminophthalimide)] benzene (BOAPIB), was synthesized from 1,4-bis [3-oxy-(N-phenylphthalimide)] benzene and hydrazine. Its structure was determined via IR, 1H NMR, and elemental analysis. A series of five-member ring, hydrazine-based polyimides were prepared from this diamine and various aromatic dianhydrides via one-step polycondensation in p-chlorophenol. The inherent viscosities of these polyimides were in the range of 0.17–0.61 dL/g. These polymers were soluble in polar aprotic solvents and phenols at room temperature. Thermogravimetric analysis (TGA) showed that the 5% weight-loss temperatures of the polyimides were near 450°C in air and 500°C in nitrogen. Dynamic mechanical thermal analysis (DMTA) indicated that the glass-transition temperatures (Tgs) of these polymers were in the range of 265–360°C. The wide-angle X-ray diffraction showed that all the polyimides were amorphous. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermally reactive aromatic polyamides
Journal of Polymer Science Part A: Polymer Chemistry, 1988
Synopsis 2,5-Bk(phenylethynyl)terephthaloyl chloride and 4,&bis-(phenylethynyl)isophthaloyl chloride were synthesized in a multistep reaction scheme from 2,5-dibromoterephthaldehyde and 4,6dibromoisophthaldehyde, respectively. Low temperature solution polycondenaation of these novel monomers and tolane2,4'-dicarbonyl chloride with aromatic diamines yielded aromatic polyamides containing phenylethynyl moieties. Inherent viscosities of 0.20-0.51 dL/g were recorded. Attempts to carry out the homopolymerization of 2-(3-aminophenylethynyl)benmyl chloride hydrochloride under similar conditions led to low molecular weight polyamide. Under dif€erential scanning calorimetry and thermal mechanical analysis, the polyamides exhibited strong exotherms with onset Occurring in the 185-225OC range. The exothemx were attributable to intramolecular cycloaddition of phenylethynyl moieties with amide groups to give polybenzalphthalimidine structures. Curing of a pressed pellet specimen for 16 h at 250°C under a nitrogen atmosphere resulted in partial conversion to a polybenzalphthalimidine structure with a concomitant increase in the polymer glass transition temperature. Isothermal aging in air of the cured specimen at 316OC (S O O O F) led to 25% weight loas after 200 h.
Fluorinated Polyimides Based on 3,3-Bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]phthalide
Polymer Journal, 2004
A novel fluorinated diamine monomer, 3,3-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]phthalide (II), was prepared through the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride with phenolphthalein in the presence of potassium carbonate to yield the intermediate dinitro compound I, followed by catalytic reduction with hydrazine and Pd/C. Polyimides V were synthesized from diamine II and various aromatic dianhydrides III a{f via thermal or chemical imidization of poly(amic acid)s. These polymers had inherent viscosities ranging from 0.63 to 0.95 dL/g and were soluble in a variety of organic solvents. V a{f films had tensile strengths of 105-125 MPa, elongations to break of 9-12%, and initial modulus of 2.35-2.65 GPa. The glass transition temperatures of these polymers were recorded 259-320 C, and no significant weight loss was observed below a temperature of 500 C in nitrogen or in air. Compared with nonfluorinated homologues VI, V showed better solubility and lower color intensity, dielectric constant (2.70-3.11 at 1 MHz), and moisture absorption (0.12-0.27 wt %). In particular, V c{f afforded lightly colored films, which had cutoff wavelengths lower than 380 nm and yellowness index (b à values) ranging from 9 to 25. On comparing thermal imidized polymers with chemical imidized ones, films V a{f ðCÞ showed a lower color intensity than V a{f ðHÞ did. [
A series of poly(amideimide)s were prepared by the reaction of two new anhydride acidchloride monomers with aromatic diamines. 4-(p-Carboxyphenoxy)phthalic anhydride was synthesized by nucleophilic displacement reaction of N-methyl-4-nitrophthalimide with p-hydroxybenzoic acid, followed by hydrolysis. The tricarboxylic acid was converted to the corresponding anhydride acidchloride. 4-(p-Carboxybenzoyl)phthalic anhydride was synthesized by FriedeleCraft's acylation of toluene with Nphenylphthalimide-4-carbonylchloride, which was then converted to anhydride acidchloride of 4-(pcarboxybenzoyl)phthalic acid. The monomers were characterized by IR and NMR. Several PAI were prepared by the reaction of these anhydride acidchloride monomers with aromatic diamines. The inherent viscosities of the polymers were in the range of 0.42e0.58 dL/g. All polymers were soluble in polar aprotic solvents. The polymers showed good thermal stability and T g values were in the range of 226e269 C. X-Ray diffractograms of polymers indicate amorphous nature of these polymers.
Polymer, 2001
This study introduces a novel high-temperature semicrystalline polyimide, which is based on an ether diamine (TPER or 1,3(4)APB) and BTDA dianhydride, both being commercially available. Phthalic anhydride is used as an endcap for improving thermal stability. The polyimide displays a T g at ca. 2308C and two prominent melting endotherms at 360 and 4168C, respectively, with a sharp recrystallization exotherm following the lower melting endotherm. Signi®cant recrystallization ability from the melt (at 4508C for 1 min) is observed with cooling rates faster than 2008C/min necessary to quench the polymer into an amorphous state. The effect of small variations in the melt crystallization temperature on the morphology and the melting behavior is discussed. DSC, hot stage polarized optical microscopy and WAXD experiments are utilized to interpret the melting behavior with respect to different causes. Some indirect evidence suggests that the two prominent melting endotherms may be due to different crystal unit cell structures. For crystallization temperatures higher than 3508C, an isothermal lamellar thickening phenomenon occurs with signi®cant increases in the peak melting point (10±148C) observed for longer crystallization times. q
Journal of Polymer Science Part A: Polymer Chemistry, 2006
A series of molecular-weight-controlled aromatic polyimides based on 4,4'-oxydiphthalic anhydride (ODPA), 1,4-bis(4-amino-2-trifluoromethylphenoxy) benzene (6FAPB) and 4,4'-diaminodiphenylsulphone (4,4'-DDS) were synthesized in the presence of phthalic anhydride (PA) as end-capping agent. The effect of molecular weight on solubility, melt viscosity, thermal and mechanical properties of polyimides was investigated. Experimental results demonstrated that these polyimides have good solubility not only in most of polar aprotic solvents but also in some of common organic solvents, such as DMSO and THF. Homogeneous and stable polyimide solutions with solid content as high as 40-45 wt.% could be achieved. High-quality polyimide films could be obtained by casting the polyimide solutions onto glass plate followed by baking at a relatively low temperature. The polyimide films exhibited outstanding thermal and mechanical properties. The rheological behavior of these polyimides depends on their molecular weight. Adhesive properties of polyimide films bonded to stainless steel were evaluated by lap shear strength (LSS) test. The bonding conditions were optimized with respect to the melt temperature, bonding pressure and time, as well as thickness of the adhesive layer. It is found that the polyimides with moderate molecular weight exhibited better adhesive properties.
Thermal Behaviour of Polymers Based on Nadimides
Journal of Thermal Analysis and Calorimetry, 2000
Carbocationic polymerization of N-ortho/meta/para tolyl-exo-norbornene dicarboximide (nadimide) was carried out using Pd(II) catalyst. Under similar conditions of polymerization, poly(N-m-tolyl nadimide) showed higher molecular mass compared to poly(N-p-tolyl nadimide) and poly(N-o-tolyl nadimide). Thermal stability of these polymers was evaluated by dynamic thermogravimetry in nitrogen atmosphere. The polymers were stable up to 460°C and lost mass above this temperature in a single step. The characteristic decomposition temperature and char yield of these polymers were higher than the polymers prepared by using ring opening metathesis polymerization. The difference has been attributed to the presence of rigid bicyclic ring structure in these polymers.