Synthesis and characterization of new polyimides and polyamide-imides containing azomethine group in the polymer backbone (original) (raw)
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Synthesis and Characterization of PoIyimides and PoIyamide- imides Containing Azomethine Linkages
Polymer International
Polyimides and polyamide-imides containing azomethine linkages in the polymer backbone have been synthesized from 4,4'-bis(4-isocyanatobenzylidene)-diaminodiphenylether (ODAI), 4,4-bis(4-isocyanato- benzylidene)-diaminodiphenylmethane (MADI), 4,4-bis(4-isocyanatobenzylidene)-diaminodiphenylsulphone (SDAI), pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) and trimellitic anhydride (TMA) by a one-step process. The diisocyanates ODAI, MDAI and SDAI were prepared from the corresponding diacids, namely, 4,4-bis(4-carboxybenzylidene)-diaminodiphenylether (ODAA), 4,4'-bis(4-carboxybenzylidene)-diaminodiphenylmethane (MDAA) and 4,4'-bis-(4-carboxybcnzylidene)- diaminodiphenylsulphone (SDAA) by a Weinstock-modified Curtius rearrangement method. All the polycondensation reactions were conducted in N-methyl-2-pyrrolidone (NMP) under identical conditions and the polymers obtained were characterized by IR spectroscopy, solution viscos...
Synthesis and characterization of some novel aromatic polyimides
European polymer journal, 2005
Three new diamines 1,2-di(p-aminophenyloxy)ethylene, 2-(4-aminophenoxy)methyl-5-aminobenzimidazole and 4,4-(aminopheyloxy) phenyl-4-aminobenzamide were synthesized and polymerized with 3,3 0 ,4,4 0 -benzophenone tetracarboxylic acid dianhydride (BP), 4,4 0 -(hexafluoroisopropyledene)diphthalic anhydride (HF) and 3,4,9,10-perylene tetracarboxylic acid dianhydride (PD) either by one step solution polymerization reaction or by two step procedure. The later includes ring opening poly-addition to give poly(amic acid), followed by cyclodehydration to polyimides with the inherent viscosities 0.62-0.97 dl/g. Majority of polymers are found to be soluble in most of the organic solvents such as DMSO, DMF, DMAc, m-cresol even at room temperature and few becomes soluble on heating. The degradation temperature of the resultant polymers falls in the ranges from 240°C to 550°C in nitrogen (with only 10% weight loss). Specific heat capacity at 300°C ranges from 1.1899 to 5.2541 J g À1 k À1 . The maximum degradation temperature ranges from 250 to 620°C. T g values of the polyimides ranged from 168 to 254°C.
European Polymer Journal, 2005
A new kind of aromatic diamine monomer containing pyridine unit, 2,6-Bis(3-aminobenzoyl)pyridine (BABP), was synthesized by the Friedel-Crafts acylation of benzene with 2,6-pyridinedicarbonyl chloride to form 2,6-Dibenzoylpyridine (DBPY), the nitrification of DBPY with nitric acid (99%) to form dinitro compound (BNBP), and the deoxidization of BNBP using SnCl 2 in ethanol, successively. The diamine monomer BABP reacted with various aromatic dianhydrides to prepare a series of poly(amic acid), meanwhile, corresponding polyimides were obtained via the thermal or chemical imidzation procedures of the resulting poly(amic acid). The poly(amic acid) solutions in N,N-dimethyacetamide (DMAc) would be coated onto a plane-glass and could be thermally converted into transparent and tough polyimides films. The compositions, structures of the resulting monomer including corresponding intermediates, as well as the structure, physical property, thermostability, thermal behavior, solubility and solution viscosity of the resulting polyimides were characterized by means of FT-IR, 1 H-NMR, 13 C-NMR, MS (EI), DSC, TGA, wide-angle X-ray diffraction, elemental analysis methods, and the effects of reactive conditions on the above structures and properties were studied, too.
Polymer, 2005
A new kind of aromatic diamine monomer containing pyridine unit, 2,6-bis(4-aminophenoxy-4 0 -benzoyl)pyridine (BABP), was synthesized successfully. The Friedel-Crafts acylation of phenyl ethyl ether with 2,6-pyridinedicarbonyl chloride formed 2,6-bis(4,4 0 -dihydroxybenzoyl)pyridine (BHBP), BHBP was changed into 2,6-bis(4-nitrophenoxy-4 0 -benzoyl)-pyridine (BNBP) by the nucleophilic substitution reaction of it and p-chloronitrobenzene, and BNBP was reduced with SnCl 2 and HCl in ethanol to form the diamine monomer BABP finally, the diamine monomer BABP could be obtained in quantitative yield. A series of novel polyimides were prepared by polycondensation of BABP with various aromatic dianhydrides in N-methy-2-pyrrolidone (NMP) via the conventional two-step method. Experimental results indicated that some of the polyimides were soluble both in strong dipolar solvents (N-methy-2-pyrrolidone or N,N-dimethylacetamide) and in common organic solvents tetrahydrofuran. The resulting polyimides showed exceptional thermal and thermooxidative stability, no weight loss was detected before a temperature of 450 8C in nitrogen, and the values of glass-transition temperature of them were in the range of 208-324 8C. Wide-angle X-ray diffraction measurements revealed that these polyimides were predominantly amorphous. q
Polyimides and polyamide–imides containing arylene sulfone ether linkages
Journal of Applied Polymer Science, 1990
Polyimides and polyamide-imides containing arylene sulfone ether linkages were synthesized from 4,4'-bis (4-isocyanatophenoxy) diphenylsulfone (SPI), 4,4'-bis( 3-isocyanatophenoxy) diphenylsulfone ( SMI ) , pyromellitic dianhydride ( PMDA) , 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), and trimellitic anhydride (TMA) using one-step method. The diisocyanates SPI and SMI were synthesized from 4,4'-bis (4-carboxyphenoxy) diphenylsulfone (SPA) and 4,4'bis (3-carboxyphenoxy ) diphenylsulfone ( SMA) by a Weinstock-modified curtius rearrangement method. All the polycondensation reactions were carried out in N-methyl-2-pyrrolidone ( NMP) and the polymers obtained were characterized by infrared spectroscopy, solution viscosity, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and X-ray diffraction.
Polymer International, 2004
A novel pyridine-containing aromatic dianhydride monomer, 2,6-bis[4-(3,4-dicarboxyphenoxy)benzoyl]pyridine dianhydride, was synthesized from the nitro displacement of 4-nitrophthalonitrile by the phenoxide ion of 2,6-bis(4-hydroxybenzoyl)pyridine, followed by acidic hydrolysis of the intermediate tetranitrile and cyclodehydration of the resulting tetraacid. A series of new polyimides holding pyridine moieties in main chain were prepared from the resulting dianhydride monomer with various aromatic diamines via a conventional two-stage process, i.e. ring-opening polycondensation forming the poly(amic acid)s and further thermal or chemical imidization forming polyimides. The inherent viscosities of the resulting polyimides were in the range of 0.51-0.68 dL/g, and most of them were soluble in aprotic amide solvents and cresols, such as N,Ndimethylacetamide, N-methyl-2-pyrrolidone, and m-cresol, etc. Meanwhile, some strong and flexible polyimide films were obtained, which have good thermal stability with the glass transition temperatures of 221-278 8C, the temperature at 5% weight loss of 512-540 8C, and the residue at 800 8C of 60.4-65.3% in nitrogen, as well as have outstanding mechanical properties with the tensile strengths of 72.8-104.4 MPa and elongations at breakage of 9.1-11.7%. The polyimides also were found to possess low dielectric constants.
Iranian Journal of Chemical Engineering, 2022
It is crucial to design and develop new polymers with desirable characteristics. Aromatic polyimides have been attracted more attention in comparison with other polymeric materials, because of their excellent properties, such as the high thermal stability, mechanical strength, and chemical resistance. In this work, two semi-aromatic polyimides (BCDA-mPDA and BCDA-Durene) were successfully synthesized from bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarbocylic dianhydride (BCDA), 1,3-phenylenediamine (mPDA), and 2,3,5,6-tetramethyl-1,4-phenylenediamine (Durene) to investigate the effect of methyl functional groups on the physicochemical and structural properties of the synthesized polyimides. The synthesized polyimides were characterized by the proton nuclear magnetic resonance (1H-NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, inherent viscosity measurement, and solubility test. FTIR and 1H-NMR results confirmed the chemical structure of the synthesized polyimides. XRD results showed that the presence of bulky methyl groups has led to increasing amorphous regions in the polymer structure. In addition, these new polymers were soluble in various organic solvents such as dimethylformamide (DMF), dimethylsulfoxide (DMSO), and N-methyl-2-pyrrolidone (NMP). The inherent viscosity of the synthesized polyimides was 0.65 dl/g for BCDA-Durene and 0.96 dl/g for BCDA-mPDA, which indicates the moderate molecular weight of the polymers.
Polymer Degradation and Stability, 2006
New naphthalene-ring containing ester diamines, as new monomers for the preparation of polyimides were synthesized via two successive reactions. Nucleophilic reaction of 3,5-dinitrobenzoylchloride with 1-naphthol and 2-naphthol in the presence of sodium hydroxide led to the preparation of 1-and 2-(3,5-dinitrobenzoyloxy)naphthalene, respectively. Next step was reduction of them by hydrazine hydrate/PdeC to produce 1-and 2-(3,5-diaminobenzoyloxy)naphthalene. All the prepared compounds were characterized by common spectroscopic methods. These ester containing aromatic diamines with pendent naphthalene group were used to prepare soluble polyimide copolymers via two different methods: catalyzed one-step high-temperature polycondensation in m-cresol, and two-step polycondensation in NMP and subsequent chemical dehydration. The obtained poly(ester-imide)s were characterized and their properties were studied. One-step and two-step methods for the preparation of five-membered ring polyimides were compared. Polymers prepared through one-step method showed higher yield and inherent viscosities and therefore better physical properties.