A new phenoxy-substituted aromatic diamine, 3,4′-diamino-4-phenoxybenzophenone, was synthesized by a four-step process using p-nitrobenzoyl chloride and chlorobenzene as initial compounds. By interaction of the obtained diamine with aromatic tetracarboxylic acid dianhydrides under high-temperature polycyclocondensation conditions in phenolic solvents, new high-molecular-mass soluble polyimides were prepared. 相似文献
Organo-soluble fluorinated polyimides were synthesized by the polycondensation of a new aromatic diamine α,αbis(4-amino-3,5-dimethylphenyl)-4'-fluorophenyl methane with several aromatic dianhydrides. The one-step polymerization polyimides could be soluble not only in polar aprotic solvents, such as N-methyl-2-pyrrolidinone, and N,Ndimethylacetamide, but also in common organic solvents, such as chloroform, cyclopentanone, m-cresol and so on. The polyimide films show excellent transparency with the UV-Vis cut-off lengths of 310-360 nm and light transmittances of higher than 80% in the visible region. In addition, the polyimides exhibit good thermal stability with an initial decomposition temperature (Td) higher than 530℃ and have more than 60% of residual weight retentions at 700 ℃. 相似文献
Organo-soluble fluorinated polyimides were synthesized by the polycondensation of a new aromatic diamine -bis(4-amino-3,5-dimethylphenyl)-4′-fluorophenyl methane with several aromatic dianhydrides. The one-step polymerization procedure was conducted at 180℃ in m-cresol, producing the polyimides with inherent viscosities of 0.680.76 dL•g1. The polyimides could be soluble not only in polar aprotic solvents, such as N-methyl-2-pyrrolidinone, and N,N-dimethylacetamide, but also in common organic solvents, such as chloroform, cyclopentanone, m-cresol and so on. The polyimide films show excellent transparency with the UV-Vis cut-off lengths of 310360 nm and light transmittances of higher than 80% in the visible region. In addition, the polyimides exhibit good thermal stability with an initial decomposition temperature (Td) higher than 530℃ and have more than 60% of residual weight retentions at 700℃. 相似文献
Summary: A new diamine monomer containing a crown ether was made to react with commercial diacid chlorides and dianhydrides to yield new aromatic polyamides and polyimides. The crown ether moiety was introduced as a pendant group so that the polymers showed enhanced solubility in organic solvents, good thermal properties (high transition temperatures and high thermal stability), and good film‐forming ability.
The new aromatic polyamides and polyimides bearing a benzo‐15‐crown‐5‐pendant group synthesized here. 相似文献
A new fluorinated diamine, 3,5-diamino-4-methyl-2′,3′,5′,6′-tetrafluoro-4′-trifluoromethyldiphenyloxide, was synthesized by interaction of 2,6-diamino-p-cresol with perfluorotoluene via aromatic nucleophilic substitution. New aromatic polyimides with perfluorotolyl substituents were prepared by interaction of the synthesized diamine with aromatic tetracarboxylic acid dianhydrides under conditions of high-temperature polycyclocondensation in phenolic solvents. The resulting polyimides combine high thermal characteristics with solubility in organic solvents and reduced permittivity. 相似文献
A study of the relationship between glass transition temperature of various polyimides and their conformational parameters
is presented. The dependence of glass transition temperature on the rigidity of either diamine or dianhydride component is
discussed by selecting groups of polymers based each on one diamine and different dianhydrides. The solubility of such polymers
is also discussed in connection with the rigidity of their chains. 相似文献
A novel unsymmetrical diamine monomer containing triaryl imidazole pendant group, 4-[4-(4,5-diphenyl-1H-imidazol-2-yl)phenoxy] benzene-1,3-diamine (DAI), was successfully synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-(4,5-diphenyl-1H-imidazol-2-yl)phenol, followed by palladium-catalyzed hydrazine reduction. The diamine monomer DAI polymerized with commercial available dianhydrides such as benzophenone tetracarboxylic dianhydride (BTDA), pyromellitic dianhydride (PMDA) and bicyclo[2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCDA) by using two step synthetic methods to obtain corresponding polyimides (PIs). PIs had inherent viscosity of 0.42-0.51 dL/g and exhibited excellent solubility in aprotic polar solvents such as N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), pyridine and methyl sulfoxide (DMSO). PIs showed high glass transition temperatures between 230 and 320 °C, and they were fairly stable up to a temperature above 300 and 450 °C depending on the dianhydride monomer used for the PIs preparation. 相似文献
A new aromatic ether diamine, bis[3-(4-amino-2-trifluoromethylphenoxy) phenyl] ether, was successfully synthesized via nucleophilic substitution reaction of 3,3′-oxydiphenol and 2-chloro-5-nitrotrifluoromethylbenzene, followed by a catalytic reduction. A series of new polyimides were synthesized from the diamine with various commercially available aromatic dianhydrides via a conventional two-stage process, i.e. ring-opening polyaddition forming the poly(amic acid)s and further thermal or chemical imidization forming polyimides. The resulting polyimides exhibited good solubility in polar solvents, such as N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidinone and common solvents such as chloroform, tetrahydrofuran upon heating and possessed the inherent viscosities of 0.51-0.68 dL/g. The resulting strong and flexible films exhibited excellent thermal stability with the temperature at 10% weight loss is above 502 °C and the glass transition temperature in the range of 191-232 °C. The polyimides also were found to possess high optical transparency. 相似文献
A novel method for the preparation of an asymmetric fluorinated aromatic diamine, 3,4′-bis(4-amino-2-trifluoromethylphenoxy)-benzophenone was investigated. This new diamine containing trifluoromethyl side group was synthesized from the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 3,4′-dihydroxybenzo phenone in the presence of potassium carbonate, followed by catalytic reduction with SnCl2·6H2O and concentrated hydrochloric acid. This novel diamine was used to react with different commercially available aromatic tetracarboxylic dianhydrides to prepare polyimides via thermal or chemical imidization. The polyimide properties such as inherent viscosity, solubility, thermal and surface properties were investigated to illustrate the contribution of the trifluoromethyl group and the asymmetry structure of the polyimide. The polyimides obtained had good thermal stability and the glass transition temperature values ranged from 225 to 267 °C. All of these novel polyimides held 10% weight loss at the temperature above 543 °C in air and left more than 47% residue even at 800 °C in nitrogen. The inherent viscosities of the obtained polyimides were above 0.73 dL/g and were easily dissolved in both polar, aprotic solvents and some low-boiling-point solvents. Moreover, these PI films had dielectric constants of 2.94-3.53 (1 kHz), with moisture absorption in the range of 0.07-0.34 wt%. In comparison of the PIs (5) series with the analogous symmetric PIs (6) series based on 4,4′-bis(4-amino-2-trifluoromethylphenoxy)-benzophenone, the (5) series revealed better solubility, low dielectric constant and moisture absorption. 相似文献
A new trifluoromethylated bis(ether amine), 1,5-bis(4-amino-2-trifluoromethylphenoxy)naphthalene, was synthesized in two steps starting from 1,5-dihydroxynaphthalene and 2-chloro-5-nitrobenzotrifluoride via nucleophilic aromatic substitution and catalytic reduction. A series of novel fluorinated polyimides with moderate to high molecular weights were synthesized from the diamine with various aromatic tetracarboxylic dianhydrides using a conventional two-stage process. All polyimides could afford flexible and tough films and most of them were soluble in strong polar solvents such as N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc). The polyimides showed glass-transition temperatures (Tg) in the range of 253-315 °C (by DSC) and softening temperatures (Ts) in the range of 250-300 °C (by TMA). Decomposition temperatures for 5% weight loss all occurred above 500 °C in both air and nitrogen atmospheres. The dielectric constants of these polymers ranged from 3.17 to 3.64 at 1 MHz. The properties of these fluorinated polyimides were also compared with those of polyimides prepared from 1,5-bis(4-aminophenoxy)naphthalene with the same dianhydrides. 相似文献