Soluble polyimides containing trans-diaminotetraphenylporphyrin: Synthesis and photoinduced electron transfer

5,15-Bis(4-aminophenyl)-10,20-diphenylporphyrin (trans-DATPP) was synthesized via the condensation of meso-(4-nitrophenyl)dipyrromethane and benzaldehyde. The further reaction with zinc acetylacetonate hydrate afforded zinc 5,15-bis(4-aminophenyl)-10,20-diphenylporphyrin (trans-ZnDATPP). A series of soluble polyimides based on trans-DATPP or trans-ZnDATPP, 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (PFMB) and 4,4′-hexafluoroisopropylidenediphthalic anhydride (6FDA) at various ratios was then prepared. Some physical properties of these polyimides were measured. It was found that every polyimide containing either trans-DATPP or trans-ZnDATPP had higher viscosity than the polyimide without porphyrin unit. Furthermore, the polyimides with trans-ZnDATPP showed lower viscosity than the ones without trans-ZnDATPP at approximately the same porphyrin content. Glass transition temperatures (T_gs) of polyimides containing trans-ZnDATPP were higher than polyimides containing trans-DATPP, and both were higher than polyimide without porphyrin. Steady state fluorescence spectroscopy of these polymers revealed that the quantum yield of polymers increased with higher content of free base porphyrin in the polymer chain. Time-correlated single photon counting experiments indicated these polyimides could be used in photonic applications.     

The influence of multiple ortho-substituted phenylenes on the nature of poly(ether imide)s

The new ortho-aminophenyl diamine 1,2-bis(2′-aminophenoxy)benzene has been synthesized and polymerized with 1,2-bis(3′,4′dicarboxyphenoxy)benzene dianhydride to yield a poly(ether imide) with four ortho-catenated phenylenes per structural repeat unit. The polymer has been characterized by gel permeation chromatography and MALDI-TOF mass spectrometry and shown to contain a large proportion of oligomers. The oligomers have been found to be primarily macrocyclic oligomers with two to 10 repeat units. The results are contrasted with the high-molecular-weight polyimides formed from corresponding para-aminophenoxy diamines. It is concluded that either the ortho-aminophenoxy moiety or the large sequence of ortho-catenated phenylene rings gives a high propensity for ring closure and macrocycle formation in competition with propagation.     

Syntheses and properties of polyimides based on bis(p-aminophenoxy)biphenyls

Three biphenyl unit-containing diamines,4,4-bis(p-aminophenoxy)biphenyl (III_a), 2,2-bis(p-aminophenoxy)biphenyl (III_b), and 3,3,5,5-tetramethyl-4,4-bis(p-aminophenoxy)biphenyl (III_c), were prepared by the chlorodisplacement ofp-chloronitrobenzene with 4,4-biphenol (I_a), 2,2-biphenol (I_b), and 3,3,5,5-tetramethyl-4,4-biphenol (I_c), respectively, giving the corresponding bis(nitrophenoxy) compounds II_a-c, followed by catalytic reduction with palladium (Pd) and hydrazine. Three series of polyimidesp-PI,o-PI, and Me-PI were prepared from diamines III_a-c and aromatic tetracarboxylic dianhydrides via a two-stage procedure that included ring-opening polyaddition to give poly(amic acid)s followed by thermal cyclodehydration to polyimides. The resultant three series of poly(amic acid)s had inherent viscosities of 1.09–2.83, 0.78–1.93, and 1.55–3.09 dL/g, respectively. Almost all the poly(amic acid)s could be solution-cast and thermally converted into transparent, flexible, and tough polyimide films. All the polyimides were characterized by solubility, tensile test, wide-angle X-ray scattering measurements, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Effects of the structures of aromatic diamines and dianhydrides on the properties of polyimides were investigated.     

Gas transport properties of 6FDA-TAPOB hyperbranched polyimide membrane

Physical and gas transport properties of the hyperbranched polyimide prepared from a triamine, 1,3,5-tris(4-aminophenoxy)benzene (TAPOB), and a dianhydride, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), were investigated and compared with those of linear-type polyimides with similar chemical structures prepared from diamines, 1,4-bis(4-aminophenoxy)benzene (TPEQ) or 1,3-bis(4-aminophenoxy)benzene (TPER), and 6FDA. 6FDA-TAPOB hyperbranched polyimide exhibited a good thermal stability as well as linear-type analogues. Fractional free volume (FFV) value of 6FDA-TAPOB was higher than those of the linear-type analogues, indicating looser packing of molecular chains attributed to the characteristic hyperbranched structure. It was found that increased resistance to the segmental mobility decreases the gas diffusivity of 6FDA-TAPOB, in spite of the higher FFV value. However, 6FDA-TAPOB exhibited considerably high gas solubility, resulting in high gas permeability. It was suggested that low segmental mobility and unique size and distribution of free volume holes arising from the characteristic hyperbranched structure of 6FDA-TAPOB provide effective O₂/N₂ selectivity. It is concluded that the 6FDA-TAPOB hyperbranched polyimide has relatively high permeability and O₂/N₂ selectivity, and is expected to apply to a high-performance gas separation membrane.     

Preparation and Properties of Cyano-Containing Polyimide Films Based on 2,6-Bis(4-aminophenoxy)- benzonitrile

Summary A series of cyano-containing polyimides were synthesized from 2,6-bis(4-amino- phenoxy)benzonitrile and some aromatic dianhydride monomers by solution polycondensation. The poly(amic acid) films could be obtained by solution-cast from N-methyl-2-pyrrolidinone solutions and thermally converted into tough polyimide films. Structure and physical properties of thin films of those polyimides were measured by FTIR, TGA, dynamic mechanical analysis and LCR hitester et al. Results showed that the polyimides prepared from 2,6-bis(4-aminophenoxy)- benzonitrile and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride or 4,4’-(hexafluoropropylidene)diphthalic anhydride exhibited more excellent energy-damping characteristic and excellent solubility in NMP, DMF, DMAc, DMSO, THF and CHCl₃, whereas the polyimides from 2,6-bis(4-aminophenoxy)benzonitrile and 3,3’,4,4’-biphenyltetracarboxylic dianhydride or Pyromellitic dianhydride were insoluble in polar and nonpolar organic solvents. All polyimides indicated higher glass transition temperatures, excellent thermal stability and tensile properties. Incorporating a nitrile group into the polyimide backbone would enhance the dielectric constant of the polyimide films.     

Molecular dynamics simulation of cis-1,4-polybutadiene. 2. Chain motion and origin of the fast process

Molecular dynamics (MD) simulations of cis-1,4-polybutadiene in bulk amorphous state were performed to elucidate the origin of a fast relaxation process observed by quasielastic neutron scattering (QENS) measurements. The details of the torsional motion for each dihedral angle were investigated with the torsional auto- and cross-correlation functions for several temperatures in this study. Temperature dependence of the correlation between the torsional autocorrelation and cross-correlation functions is also evaluated. The origin of the fast process of cis-1,4-polybutadiene is found to be mainly the cooperative conformational transitions of two dihedral angles located at both sides of the CH₂-CH₂ bond when the bond is in the trans conformation. The cooperative conformational transitions exhibit even below the glass transition temperature of cis-1,4-polybutadiene. The cooperative motion appears at about 50 K below the glass transition temperature, corresponding to the Vogel-Fulcher temperature.     

Synthesis and properties of fluorinated polyimides. 3. Derived from novel 1,3-bis[3′-trifluoromethyl-4′(4″-amino benzoxy) benzyl] benzene and 4,4-bis[3′-trifluoromethyl-4′(4-amino benzoxy) benzyl] biphenyl

Novel diamine monomers, 1,3-bis[3′-trifluoromethyl-4′(4″-amino benzoxy) benzyl] benzene (IV) and 4,4-bis[3′-trifluoromethyl-4′(4-amino benzoxy) benzyl] biphenyl (V) have been synthesized. These monomers lead to several novel fluorinated polyimides on reaction with different commercially available dianhydrides like pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA) or 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane (6FDA). The polyimides prepared from above two monomers on reaction with 6FDA are soluble in several organic solvents such as N,N-dimethyl formamide (DMF), N,N-dimethyl acetamide (DMAc) and tetrahydrofuran (THF). The polyimides prepared from PMDA/IV is soluble in DMF and N-methyl pyrollidone (NMP) on heating, whereas V/PMDA is insoluble in all solvents. BTDA/IV polyimide is also soluble in NMP, DMF and DMAc. These polyimide films have low water absorption rate 0.2-0.7% and low dielectric constant 2.74-3.2 at 1 MHz. These polyimides showed very high thermal stability even up to 531 °C for 5% weight loss in synthetic air and glass transition temperature up to 316 °C (by DSC) in nitrogen. All polyimides formed tough transparent films, with tensile strength up to 148 MPa, a modulus of elasticity up to 2.6 GPa and elongation at break up to 31% depending upon the exact repeating unit structure.     

Synthesis and characterization of novel fluorinated polyimides derived from 4,4′-[2,2,2-trifluoro-1-(3,5-ditrifluoromethylphenyl)ethylidene]diphthalic anhydride and aromatic diamines

A novel fluorinated aromatic dianhydride, 4,4′-[2,2,2-trifluoro-1-(3,5-ditrifluoromethylphenyl) ethylidene] diphthalic anhydride (9FDA), was synthesized, which was employed to polycondense with various aromatic diamines, including 4,4′-oxydianiline, 1,4-bis(4-aminophenoxy) benzene, 3,4′-oxydianiline and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene to produce a series of fluorinated aromatic polyimides. The fluorinated polyimides obtained had inherent viscosities ranged of 0.61-1.14 dL/g and were easily dissolved both in polar aprotic solvents and in low boiling point common solvents. High quality polyimide films could be prepared by casting the polyimide solution on glass plate followed by thermal baking to remove the organic solvents and volatile completely. Experimental results indicated that the fluorinated polyimides exhibited good thermal stability with glass transition temperature ranged of 245-283 °C and temperature at 5% weight loss of 536-546 °C. Moreover, the polyimide films showed outstanding mechanical properties with the tensile strengths of 87.7-102.7 MPa and elongation at breaks of 5.0-7.8%, good dielectric properties with low dielectric constants of 2.71-2.97 and low dissipation factor in the range of 0.0013-0.0028.     

Preparation and characterization of organosoluble polyimides based on 1,1-bis[4-(3,4-aminophenoxy)phenyl]cyclohexane and commercial aromatic dianhydrides

A bis(ether amine) III-A containing a cyclohexane cardo group, 1,1-bis[4-(4-aminophenoxy)phenyl]cyclohexane, was synthesized and used as a monomer to prepare polyimides VI-A with six commercial dianhydrides via three different procedures. The intermediate poly(amic acid)s had inherent viscosities of 0.83–1.69 dL g⁻¹ and were thermally or chemically converted into polyimides. Polyimides were also prepared by high-temperature direct polymerization in m-cresol and had inherent viscosities higher than the thermally or chemically cyclodehydrated ones. To improve the solubility of polyimides, six copolyimides were also synthesized from bis(ether amine) III-A with a pair of dianhydrides, which contained 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride or 4,4′-hexafluoroisopropylidenediphthalic anhydride. Series VI-A polyimides were characterized by the good physical properties of their film-forming ability, thermal stability, and tensile properties. A comparative study of the properties, with the corresponding polyimides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]propane, is also presented. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2750–2759, 2001     

High thermal stable thermoplastic-thermosetting polyimide film by use of asymmetric dianhydride (a-BPDA)

In order to obtain thermoplastic (before curing) and thermosetting (after curing) polyimides with high T_g for adhesive film, we prepared novel polyimides having phenylethynyl group in the side chain (44% of concentration of curing group) from asymmetric 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA), 3,4′-oxydianiline (3,4′-ODA) or 1,3-bis(4-aminophenoxy)benzene (1,3,4-APB) or 1,3-bis(3-aminophenoxy)benzene (1,3,3-APB), and 2,4-diamino-1-(4-phenylethynylphenoxy)benzene (mPDAp). Among three kinds of polymer, uncured polyimide of a-BPDA/1,3,4-APB; mPDAp had rather high T_g (265 °C, DMA) and thermoplasticity (E′ drop>10³ at T_g). After curing reaction of phenylethynyl group, the T_g of the polyimide was increased dramatically (364 °C, DMA). The polyimide derived from 1,3,4-APB having less concentration of curing group (20%) was also prepared to improve further film flexibility and toughness.     

Color lightness and highly organosoluble fluorinated polyamides, polyimides and poly(amide-imide)s based on noncoplanar 2,2′-dimethyl-4,4′-biphenylene units

A new diamine monomer containing noncoplanar methyl substitution, 2,2′-dimethyl-4,4′-bis(2-trifluoromethyl-4-aminophenoxy)biphenyl (DBTFAPB) was successfully synthesized and used in the preparation of a series of polyamides and polyimides by direct polycondensation with various aromatic dicarboxylic acids and tertacarboxylic dianhydrides. A new noncoplanar dicarboxylic acid monomer containing noncoplanar methyl substitution, 2,2′-dimethyl-4,4′-bis(2-trifluoromethyl-4-trimellitimidophenoxy)biphenyl (DBTFTPB) was also successfully synthesized by refluxing the diamine, DBTFAPB, with trimellitic anhydride in glacial acetic acid. A series of new poly(amide-imide)s were prepared directly from DBTFTPB with various diamines in N-methyl-2-pyrrolidinone (NMP). All the polymers exhibited excellent solubility in solvents, such as N-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyridine, tetrahydrofuran (THF), cyclohexanone and γ-butyrolactone at room temperature or upon heating at 70 °C. Inherent viscosities of the polymers were found to range between 0.60 and 1.34 dL g⁻¹. Gel permeation chromatography (GPC) of the polymers showed number-average and weight-average molecular weight up to 7.3×10⁴ and 17.9×10⁴, respectively. These polymers showed that the glass transition temperatures were between 230 and 265 °C, and the 10% mass loss temperatures were higher than 460 °C in nitrogen atmosphere. All the polymers could be cast into flexible and tough films from DMAc solutions. They had a tensile strength in the range of 82-124 MPa and a tensile modulus in the range of 1.9-2.9 GPa. These polymers exhibited low dielectric constants ranging from 2.87 to 4.03, low moisture absorption in the range of 0.29-3.20%, and high transparency with an ultraviolet-visible absorption cut-off wavelength in the 347-414 nm range.     

Synthesis and properties of polyimides from isomeric bis(dicarboxylphenylthio)diphenyl sulfone dianhydrides

4,4′-Bis(3,4-dicarboxyphenylthio)diphenyl sulfone dianhydride(4,4′-PTPSDA) and 4,4′-bis(2,3-dicarboxyphenylthio)diphenyl sulfone dianhydride(3,3′-PTPSDA) were synthesized from chlorophthalic anhydrides and bis(4-mercaptophenyl)sulfone. Their structures were determined via IR spectra, ¹H NMR and elemental analysis. A series of polyimides were prepared from isomeric PTPSDAs and aromatic diamines in 1-methyl-2-pyrrolidinone (NMP) via the conventional two-step method. Polyimides based on 4,4′-PTPSDA and 3,3′-PTPSDA have good solubility in polar aprotic solvents and phenols. The 5% weight-loss temperatures of isomeric polyimides were near 500 °C in N₂. DMTA and DSC analyses indicated that the glass-transition temperatures of polyimides from 3,3′-PTPSDA are higher than those of polyimides from 4,4′-PTPSDA. The wide-angle X-ray diffraction showed that all polyimides are amorphous. The polyimides from 3,3′-PTPSDA showed higher permeability but lower permselectivity compared with those from 4,4′-PTPSDA.     

Synthesis and properties of novel polyimides derived from 2,6-bis(4-aminophenoxy-4′-benzoyl)pyridine with some of dianhydride monomers

A new kind of aromatic diamine monomer containing pyridine unit, 2,6-bis(4-aminophenoxy-4′-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′-dihydroxybenzoyl)-pyridine (BHBP), BHBP was changed into 2,6-bis(4-nitrophenoxy-4′-benzoyl)-pyridine (BNBP) by the nucleophilic substitution reaction of it and p-chloronitrobenzene, and BNBP was reduced with SnCl₂ 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 °C in nitrogen, and the values of glass-transition temperature of them were in the range of 208-324 °C. Wide-angle X-ray diffraction measurements revealed that these polyimides were predominantly amorphous.     

Organosoluble and optically transparent fluorine-containing polyimides based on 4,4′-bis(4-amino-2-trifluoromethylphenoxy)-3,3′,5,5′-tetramethylbiphenyl

A novel fluorinated diamine monomer, 4,4′-bis(4-amino-2-trifluoromethylphenoxy)-3,3′,5,5′-tetramethylbiphenyl, was prepared by a nucleophilic chloro-displacement reaction of 3,3′,5,5′-tetramethyl-4,4′-biphenol with 2-chloro-5-nitrobenzotrifluoride and subsequent reduction of the intermediate dinitro compound. The diamine was reacted with aromatic dianhydrides to form polyimides via a two-step polycondensation method; formation of poly(amic acid)s, followed by thermal imidization. All the resulting polyimides were readily soluble in many organic solvents and exhibited excellent film forming ability. The polyimides exhibited high T_g (312-351 °C), good thermal stability, and good mechanical properties. Low moisture absorptions (0.2-1.1 wt%), low dielectric constants (2.54-3.64 at 10 kHz), and low color intensity were also observed.     

Colorless polyimides derived from 1S,2S,4R,5R-cyclohexanetetracarboxylic dianhydride,self-orientation behavior during solution casting,and their optoelectronic applications

A novel cycloaliphatic monomer for polyimides (PI), 1S,2S,4R,5R-cyclohexanetetracarboxylic dianhydride (H′-PMDA) is proposed in this work. H′-PMDA shows high polymerizability with various diamines in contrast to its isomer, i.e., conventional hydrogenated pyromellitic dianhydride (H-PMDA) and leads to highly flexible and colorless PI films with very high T_g's. In particular, the combinations with rigid structures of diamines give rise to PIs with significantly decreased coefficients of thermal expansion (CTE) owing to high extents of in-plane chain orientation induced by thermal imidization, whereas the H-PMDA-based counterparts do not. The decreased CTE reflects structural rigidity/linearity of the H′-PMDA-based diimide units as supported by liquid crystallinity observed in the corresponding model compound. Solution casting of a chemically imidized PI derived from H′-PMDA and 2,2′-bis(trifluoromethyl)benzidine (TFMB) results in a lower CTE than that of the thermally imidized counterpart, suggesting the presence of a self-orientation phenomenon during solvent evaporation. The mechanism is proposed in this work. H′-PMDA/TFMB and its copolymer systems can be useful as plastic substrates in image display devices and/or novel coating-type optical compensation films.     

Structure and dynamic mechanical properties of poly(ethylene terephthalate-co-4,4′-bibenzoate) fibers

Poly(ethylene terephthalate-co-4,4′-bibenzoate) (PETBB) fibers containing 5, 15, 35, 45, 55, and 65 mol% bibenzoate (BB) were melt spun. Fiber structure has been determined using wide angle X-ray diffraction, birefringence, and FTIR spectroscopy. When drawn to their respective maximum draw ratios, the structures and properties of high BB containing fibers (PETBB45, 55 and 65) are significantly different than those of PET and low BB containing fibers (PETBB5, 15, and 35). For example, 90% of the ethylene glycol units in high BB containing fibers are in the trans conformation, while only 80% of these units are in trans conformation in PET and low BB containing fibers. Overall orientation of the high BB containing fibers is higher (orientation factor f > 0.85) than those of PET and low BB containing fibers (f < 0.6). Orientation of the crystalline regions is quite high (f_cr ∼ 0.95) for both groups of fibers, while orientation of the amorphous regions (f_am) of high BB containing fibers is higher (∼0.8) than those of the PET and low BB containing fibers (∼0.4). High BB containing fibers exhibit much higher storage modulus and modulus retention with temperature than low BB containing fibers. Glass transition temperature determined from the dynamic loss tangent peak decreased with increasing BB content, while this transition completely disappeared in the high BB containing fibers. The magnitude of the secondary transition, observed at about −50 °C, decreased with increasing BB content. Another secondary transition, not observed in PET, was observed at about 70 °C in high BB containing fibers. These dynamic mechanical results have been rationalized in terms of the observed structural parameters.     

Synthesis, characterization and liquid-crystal-aligning properties of novel aromatic polypyromellitimides bearing (n-alkyloxy)biphenyloxy side chains

Novel aromatic polypyromellitimides bearing (n-alkyloxy)biphenyloxy side chains were prepared by two-step polycondensation of 1,4-phenylenediamine (PDA) and biphenyl-4,4′-diamine (BZ) with 3,6-bis[4′-(n-alkyloxy)biphenyl-4-oxy]pyromellitic dianhydrides (C_mB-PMDAs, m = 6, 8, 10, 12), which had been synthesized by the nucleophilic substitution of N,N′-diphenyl-3,6-dibromopyromellitimides with sodium 4-(n-alkyloxy)biphenoxides. Inherent viscosities of the poly(amic acid)s were in the 0.26-0.62 dL/g range. Poly{1,4-phenylene-3,6-bis[4′-(n-alkyloxy)biphenyl-4-oxy]pyromellitimide}s (C_mB-PPIs) and poly{4,4′-biphenyl-3,6-bis[4′-(n-alkyloxy)biphenyl-4-oxy]pyromellitimide}s (C_mB-BPIs) obtained in films by thermal imidization of the corresponding poly(amic acid)s were characterized by FT-IR spectroscopy and elemental analysis, and their crystalline structure and thermal properties were measured and discussed with respect to the side chain length. After the polyimide films were surface-treated by rubbing with velvet fibers, standard liquid crystal (LC) cells containing 4-cyano-4′-n-pentylbiphenyl (5CB) were fabricated and their LC-aligning properties were investigated in terms of pretilt angle. The pretilt angles were remarkably affected by side chain length and on surface of the polyimides with m = 6 and 8 LCs aligned parallel to the rubbing direction while on surface of the polyimides with m = 10 and 12 they aligned nearly or completely vertical to the rubbing direction.     

Generation of polyacetylene sulfoxide radicals through spin migration from the main-chain to the sulfoxide moiety in the side chain of poly[p-(n-butylsulfoxide)phenylacetylene] prepared with a [Rh(norbornadiene)Cl]2 catalyst

A phenylacetylene bearing an n-butylsulfoxide group, i.e., p-(n-butylsulfoxide)phenylacetylene (1) was prepared in high yields using the [Rh(norbornadiene)Cl]₂-NEt₃ catalyst in the presence of various solvents under mild conditions. The resulting polymer, poly[p-(n-butylsulfoxide)phenylacetylene] (poly(1)), was characterized in detail by ¹H NMR, ESR, laser Raman, and diffuse reflective UV-vis methods. The data clearly showed that cis-to-trans isomerization of the polymer can be induced when pressure is imposed to the polymer at room temperature, rotationally breaking the cis CC bonds to generate the cis and trans radicals. Further, the spin density in the cis radical was migrated from the main-chain to the sulfoxide moiety as the side chain of the phenyl ring to magnetically interact with the first two methylene protons in the n-butyl group giving a triplet line ESR spectrum with an extremely large g value, g = 2.0081.     

Synthesis and characterization of novel fluorinated polyimides derived from bis[4-(4′-aminophenoxy)phenyl]-3,5-bis(trifluoromethyl)phenyl phosphine oxide

A novel fluorinated aromatic diamine, bis[4-(4′-aminophenoxy)phenyl]-3,5-bis(trifluoromethyl)phenyl phosphine oxide, was synthesized. A series of new fluorinated polyimides containing phosphine oxide was prepared from the novel diamine with various commercially available aromatic dianhydrides. All the fluorinated polyimides show high glass transition temperatures, excellent thermal stability, and good solubility in common organic solvents.     

Synthesis and characterization of novel polyimides derived from 1,1-bis[4-(4′-aminophenoxy)phenyl]-1- [3″,5″-bis(trifluoromethyl)phenyl]-2,2,2-trifluoroethane

A novel fluorinated aromatic diamine monomer, 1,1-bis[4-(4′-aminophenoxy)phenyl]-1-[3″,5″-bis(trifluoromethyl)phenyl]-2,2,2-trifluoroethane(9FTPBA), was synthesized by coupling 3′,5′-bis(trifluoromethyl)-2,2,2-trifluoroacetophenone with 4-nitrophenyl phenyl ether under the catalysis of trifluoromethanesulfonic acid, followed reduced by reductive iron and hydrochloric acid. A series of new fluorine-containing polyimides having inherent viscosities of 0.96-1.23 dl/g was synthesized from the novel diamine with various commercially available aromatic dianhydrides using a standard two-stage process with thermal imidization and chemical imidization of poly(amic acid) films. All the fluorinated polyimides were soluble in many polar organic solvents such as NMP, DMAc, DMF, and m-cresol, as well as some of low boiling point organic solvents such as chloroform and acetone. The polymer films have good thermal stability with the glass transition temperature of 223-225 °C, the temperature at 5% weight loss of 535-568 °C in nitrogen, and have outstanding mechanical properties with the tensile strengths of 68-89 MPa, initial moduli of 2.14-2.19 GPa, and elongations at breakage of 3.2-10.5%.