Preparation of Transparent Polyimides Derived from cis‐ and trans‐Dicyclohexyl‐3,3′,4,4′‐tetracarboxylic Dianhydrides

Two series of alicyclic polyimides composed of cis‐ and trans‐dicyclohexyl‐3,3′,4,4′‐tetracarboxylic dianhydrides (DCDAs) and aromatic diamines were prepared. All cis‐polymers could be readily prepared both in a one‐step method and a two‐step method. However, a two‐step method is preferably applied in the preparation of trans‐polymers, because in a one‐step method the trans‐configuration is partially lost at higher temperatures. These polyimide solutions could be cast into tough and flexible films, which were characterized by inherent viscosity, GPC, DSC, TGA measurements, and UV‐vis spectroscopy. The glass transition temperatures (T_g's) of the polymers were in the range of 210–270°C and the 5% weight loss temperatures were around 480°C for all PIs prepared. The optical transmittances of these films were more than 80% at 350 nm for ca. 15 μm thickness.     

Synthesis and characterization of organosoluble and transparent polyimides derived from trans‐1,2‐bis(3,4‐dicarboxyphenoxy)cyclohexane dianhydride

A novel dianhydride, trans‐1,2‐bis(3,4‐dicarboxyphenoxy)cyclohexane dianhydride (1,2‐CHDPA), was prepared through aromatic nucleophilic substitution reaction of 4‐nitrophthalonitrile with trans‐cyclohexane‐1,2‐diol followed by hydrolysis and dehydration. A series of polyimides (PIs) were synthesized from one‐step polycondensation of 1,2‐CHDPA with several aromatic diamines, such as 2,2′‐bis(trifluoromethyl)biphenyl‐4,4′‐diamine (TFDB), bis(4‐amino‐2‐trifluoromethylphenyl)ether (TFODA), 4,4′‐diaminodiphenyl ether (ODA), 1,4‐bis(4‐aminophenoxy)benzene (TPEQ), 4,4′‐(1,3‐phenylenedioxy)dianiline (TPER), 2,2′‐bis[4‐(3‐aminodiphenoxy)phenyl]sulfone (m‐BAPS), and 2,2′‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]sulfone (6F‐BAPS). The glass transition temperatures (T_gs) of the polymers were higher than 198°C, and the 5% weight loss temperatures (T_d5%s) were in the range of 424–445°C in nitrogen and 415–430°C in air, respectively. All the PIs were endowed with high solubility in common organic solvents and could be cast into tough and flexible films, which exhibited good mechanical properties with tensile strengths of 76–105 MPa, elongations at break of 4.7–7.6%, and tensile moduli of 1.9–2.6 GPa. In particular, the PI films showed excellent optical transparency in the visible region with the cut‐off wavelengths of 369–375 nm owing to the introduction of trans‐1,2‐cyclohexane moiety into the main chain. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42317.     

Synthesis and characterization of side‐chain polyimides for second‐order nonlinear optics via a post‐azo‐coupling reaction

A two‐step, generally applicable synthetic approach for nonlinear optical (NLO) side‐chain polyimides was developed. This included the preparation of a preimidized, organosoluble polyimide with benzene moiety pendant from main chains, followed by the covalent bonding of the NLO chromophores onto the polyimide backbone via a post‐azo‐coupling reaction. The degree of functionalization of polyimides was estimated by UV‐VIS spectroscopy. The glass transition temperature (T_g) of a polyimide decreased by only 10–20°C after the functionalization, which was much smaller than the decrease in T_g when the chromophores were chemically bonded to the polyimide main chains through an ether linkage using a post‐Mitsunobu condensation. The solubility and thermal stability of polyimides were also studied. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 290–295, 2000     

Synthesis and properties of novel soluble and high Tg poly(ether imide)s from diamine containing 4,5‐diazafluorene and trifluoromethyl units

The synthesis and properties of soluble, high T_g and transparent aromatic polyimides containing 4,5‐diazafluorene and trifluoromethyl units in the polymer backbone on the basis of a novel diamine monomer, 9,9‐di[4‐(4‐amino‐2‐trifluoromethyl phenoxy)phenylene]‐4,5‐diazafluorene, are described. Incorporation of 4,5‐diazafluorene and trifluoromethyl groups into rigid polyimides improves their solubility and transparency without decreasing their physical properties. All of the thermal imidization polyimides are soluble at room temperature in aprotic and protic polar solvents such as N,N‐dimethylacetamide, N,N′‐dimethylformamide, dimethylsulfoxide, pyridine and m‐cresol and can be solution cast into transparent, flexible and tough films. These films have a UV–visible absorption cutoff wavelength at 386–407 nm and light transparencies of 73%–84% at a wavelength of 550 nm. In addition, the polymers exhibit high thermal stability with a glass transition temperature (T_g) of 305 to 362 °C and 5% weight loss at temperatures ranging from 525 to 543 °C in nitrogen and from 521 to 538 °C in air. The polyimide films possess tensile strengths in the range 79 ? 113 MPa, a tensile modulus of 1.75 – 2.10 GPa and elongations at break of 7% ? 16%. © 2014 Society of Chemical Industry     

One‐pot synthesis of polyetherimides from bis(chlorophthalimide) and dichlorodiphenylsulfone in diphenylsulfone

Polyetherimides and copolymers have been synthesized in one pot from bis(chlorophthalimide), dichlorodiphenylsulfone, and bisphenolate using diphenylsulfone as the solvent. The inherent viscosities of the obtained polyimides are in the range of 0.32–0.72 dL/g, and the structures of polyimides were confirmed by IR and elemental analyses. All of the polyimides have good solubility in common organic solvents. The 5% weight‐loss temperatures of the polyimides were 429–507°C in air. The glass transition temperatures (T_g) of 4,4′‐(9‐fluorenylidene) diphenol‐based polyimides are in the range of 253–268°C. The T_g of bisphenol A‐based polyimides is in the range of 198–204°C, while the T_g change inconspicuously when the ratios of diphenylsulfone increase. The wide‐angle X‐ray diffraction showed that all polyimides prepared are amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4584–4588, 2006     

Synthesis and properties of novel alicyclic‐functionalized polyimides prepared from natural—(D)‐camphor

In this article, a new alicyclic‐functionalized diamine, 1,3‐bis(4‐aminophenoxymethylene)‐1,2,2‐trimethylclopentane (BAMT) was successfully synthesized starting from natural —(D)‐camphor through four reaction steps of oxidation to offer a dicaboxylic acid, reduction to offer a diol, nucleophilic substitution to give a dinitro compound and then reduction to give the final diamine. Two alicyclic‐containing polyimides were prepared by polycondensing BAMT with 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 4,4′‐oxydiphthalicanhydride (ODPA), respectively. For the studies of the structure–property relationships of the polyimides, one aromatic polyimide of 4, 4′‐oxydianiline (ODA) polycondensed with ODPA was prepared in comparison. The alicyclic‐containinig polyimides PI (BPDA‐BAMT) and PI (ODPA‐BAMT) maintain good thermal properties with glass transition temperatures (T_g) of 257°C and 240°C, and temperatures at 5% weight loss (T₅) of 443°C and 436°C in nitrogen, respectively. The alicyclic polyimides exhibit tensile strengths of 91.9–133 MPa, Young's moduli of 2.75—3.24 GPa, and elongations at break of 5.6–18%. Compared with the aromatic polyimide PI (ODPA‐ODA), PI (ODPA‐BAMT) shows improved transparency with the UV‐Vis transmittance at 500 nm over 80%. In addition, PI (ODPA‐BAMT) displays better solubility than PI (ODPA‐ODA), which has been confirmed by the bigger d‐spacing value of PI (ODPA‐BAMT) than that of PI (ODPA‐ODA) calculated from the Wide‐angle X‐ray Diffraction spectra. This study indicates that the renewable forestry compound, such as natural —(D)‐camphor, could be a good origin for the structural designing and preparation of alicyclic‐containing polyimides with outstanding combined features suitable for advanced microelectronic and optoelectronic applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polyimides derived from 1,4‐bis [3‐oxy‐(N‐aminophthalimide)] benzene

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 (T_gs) 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     

Preparation and electro‐optic properties of novel Y‐type polyimides with highly enhanced thermal stability of second harmonic generation

BACKGROUND: In the development of nonlinear optical (NLO) polymers for electro‐optic device applications, stabilization of electrically induced dipole alignment is one of the important criteria. Polyimides for NLO applications have attracted attention because of their high T_g values and high thermal stability. In this work we designed and synthesized a new type of NLO polyimide, in which the pendant NLO chromophores are parts of the polymer backbone. These mid‐type NLO polymers are expected to have the merits of both main‐chain and side‐chain NLO polymers: stabilization of dipole alignment and good solubility. RESULTS: 3,4‐Bis‐(3,4‐dicarboxyphenylcarboxyethoxy)‐4′‐nitrostilbene dianhydride was prepared and reacted with the corresponding aromatic diamine to yield unprecedented Y‐type polyimides containing 3,4‐dioxynitrostilbenyl groups as NLO chromophores, which constituted parts of the polymer backbones. The resulting polyimides are soluble in polar solvents such as dimethylformamide and dimethylsulfoxide. These polymers showed a thermal stability up to 320 °C in thermogravimetric thermograms with T_g values obtained from differential scanning calorimetry thermograms in the range 143–164 °C. The second harmonic generation (SHG) coefficients (d₃₃) of poled polymer films at the 1064 nm^?1 fundamental wavelength were around 9.45 × 10^?18 C. CONCLUSION: The dipole alignment exhibited exceptionally high thermal stability even at 30 °C higher than T_g. There was no SHG decay below 180–190 °C because of the partial main‐chain character of the polymer structure, which is acceptable for NLO device applications. Copyright © 2007 Society of Chemical Industry     

Investigations on the polyimides derived from unfunctionalized symmetric cyclopentyl‐containing alicyclic cardo‐type dianhydride

This study presents an investigation on polyimides derived from a unfunctionalized symmetric cyclopentyl‐containing alicyclic cardo‐type dianhydride with ester linkage 1,1‐bis(4‐(3,4‐dicarboxylbenzoyloxy)phenyl)cyclopentylene dianhydride (BDPCP) that was readily accessed starting from cyclopentanone through two steps in high yield. Two series of polyimides, Cardo‐type series (CPI‐x) and analogous aromatic series (ArPI‐x) were prepared from condensation of BDPCP and aromatic 3,3′,4,4′‐Oxydiphthalic dianhydride with four aromatic diamines, respectively. Comparative studies revealed that CPI polymers show more favorable properties including better solubility in organic solvents, higher transparency with lower cut‐off wavelength (λ₀) ranging in 395–375 nm than 425–405 nm, lower water absorption ranging in 0.66–1.14% and surface energy 23.71–32.77 mN/m than 1.01–1.28% and 29.52–41.99 mN/m of ArPI analogs. Meanwhile, CPI series exhibit considerable mechanical properties with tensile strengths ranging in 87.6–102.9 MPa, elongations at break 6.6–8.9%. Owing to the moderate strain in cyclopentyl ring, CPI series retain good thermal properties with the glass transition temperature (T_g) in the range of 217–271°C. Dynamic dielectric measurement revealed that Cardo‐type dianhydride BDPCP endows CPI‐4 film with lower dielectric constant (ε′) 3.34 at 1 MHz and 25°C and dielectric loss (ε′′) 0.0064 at 1 kHz and 25°C than 3.49 and 0.013 for ArPI‐4 film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42670.     

Preparation and properties of melt‐processable polyimides based on fluorinated aromatic diamines and aromatic dianhydrides

Two series of melt‐processable polyimides were prepared from 4,4′‐bis(3‐amino‐5‐trifluoromethylphenoxy)biphenyl (m‐6FBAB) and 4,4′‐bis(4‐amino‐5‐trifluoromethylphenoxy) biphenyl (p‐6FBAB) with various aromatic dianhydrides. The effects of the chemical structures of the polyimides on their properties, especially the melt processability and organic solubility, were investigated. The experimental results demonstrate that some of the fluorinated aromatic polyimides showed good melt processability at elevated temperatures (250–360°C) with relatively low melt viscosities and could be melt‐molded to produce strong and tough polyimide sheets. Meanwhile, the polyimides showed excellent organic solubility in both polar aprotic solvents and common solvents to give stable polyimide solutions with high polymer concentrations and relatively low viscosities. Thus, we prepared high‐quality polyimide films by casting the polyimide solutions on glass plates followed by baking at relatively low temperatures. The polyimides derived from m‐6FBAB showed better melt processability and solubility than the p‐6FBAB based polymers. The melt‐processable polyimides showed a good combination of thermal stability and mechanical properties, with decomposition temperatures of 547–597°C, glass‐transition temperatures in the range 205–264°C, tensile strengths of 81.3–104.9 MPa, and elongations at break as high as 19.6%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of organo‐soluble fluorinated polyimides

A novel fluorinated diamine monomer with a keto group, 4‐[4‐amino‐2‐trifluoromethyl phenoxy]‐4′‐[4‐aminophenoxy]benzophenone (ATAB) was prepared by reacting dihydroxybenzophenone with 4‐chloronitrobenzene and 2‐chloro‐5‐nitrotrifluoromethylbenzene in the presence of potassium carbonate followed by catalytic reduction with palladized carbon (10%). Fluorinated polyimides IVa–e were synthesized from the diamine mentioned above via a two‐step method (thermal and chemical imidization). Polyimides IVa–e have inherent viscosities in the range 0.65–1.06 dL g^?1 (thermal imidization) and 0.82–1.56 dL g^?1 (chemical imidization). The polyimides prepared by chemical imidization exhibit excellent solubility. Polyimide films exhibit tensile strength, elongation and tensile modulus in the ranges 96–106 MPa, 9–13% and 1.1–1.7 GPa, respectively. The T₁₀ values of the polyimides are in the range 540–598 °C in nitrogen and 545–586 °C in air, with more than 50–60% char yield. They have T_g values between 244 and 285 °C. The prepared polyimides show cut‐off wavelengths in the range 365–412 nm and transmittance at 450 nm in the range 80.9–94.2%. The dielectric constants of the polyimide films are in the range 3.10–3.77 at 1 kHz and 3.04–3.66 at 10 kHz, with moisture absorption of 0.14–0.40%. Copyright © 2006 Society of Chemical Industry     

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 of cardo containing asymmetric poly(ether‐naphthalimide‐phthalimide)s

A series of cardo based asymmetric polyimides containing bulky rigid naphthalimide and phthalimide groups were prepared from asymmetric monomer bishaloimide and bisphenols by solution polycondensation. Bishalo(naphthalimide‐phthalimide) monomers containing different terminal leaving groups (Cl, F, NO₂) were synthesized, and the reactivity difference of these monomers was compared for the successful synthesis of polyimides. The inherent viscosities of the polyimides were in the range 0.51 ? 0.60 dL g^?1 in N ‐methyl‐2‐pyrrolidone at 30 °C. These polyimides demonstrated good organosolubility and mechanical properties with tensile strengths of 93 ? 120 MPa, tensile moduli of 3.5 ? 5.3 GPa and elongations at break of 2.8% ? 4.3%. The polyimides showed high glass transition temperatures (T _g) ranging from 330 to 363 °C. The 10% weight loss (T _10%) of asymmetric polyimides reached 436 ? 500 °C in nitrogen and 417 ? 476 °C in air. The water uptake of the polyimides was in the range 0.35% ? 0.72%. © 2017 Society of Chemical Industry     

Synthesis of highly soluble and transparent polyimides

A novel aromatic diamine, 3,3′‐diisopropyl‐4,4′‐diaminophenyl‐4″‐methyltoluene with a 4‐methylphenyl pendant group and isopropyl side groups, was designed and synthesized in this study. Then it was polymerized with various aromatic dianhydrides including pyromellitic dianhydride, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 4,4′‐oxydiphthalic anhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride via a one‐pot high temperature polycondensation procedure to produce a series of aromatic polyimides. These polyimides exhibited excellent solubility even in common organic solvents, such as chloroform and tetrahydrofuran. The flexible and tough films can be conveniently obtained by solution casting. The films were nearly colorless and exhibited high optical transparency, with the UV cutoff wavelength in the range 302–365 nm and the wavelength of 80% transparency in the range 385–461 nm. Moreover, they showed low dielectric constants (2.73–3.23 at 1 MHz) and low moisture absorption (0.13%–0.46%). Furthermore, they also possessed good thermal and thermo‐oxidative stability with 10% weight loss temperatures (T_10%) in the range 489–507 °C in a nitrogen atmosphere. The glass transition temperatures of all polyimides are in the range 262–308 °C. Copyright © 2012 Society of Chemical Industry     

Synthesis and characterization of soluble poly(arylene ether ketone)s with high glass transition temperature based on 3,6‐bi(4‐fluorobenzoyl)‐N‐alkylcarbazole

3,6‐bi(4‐fluorobenzoyl)‐N‐methylcarbazole and 3,6‐bi(4‐fluorobenzoyl)‐N‐ethylcarbazole were synthesized and used to prepare poly(arylene ether ketone)s (PAEKs) with high glass transition temperatures (T_g) and good solubility. High molecular weight amorphous PAEKs were prepared from these two difluoroketones with hydroquinone, phenolphthalein, 9,9‐bis(4‐hydroxyphenyl)fluorene and 4‐(4‐hydroxylphenyl)‐2,3‐phthalazin‐1‐one, respectively. All these polymers presented high thermal stability with glass transition temperatures being in the range 239–303 °C and a 5% thermal weight loss temperature above 460 °C. Compared with the T_g of phenolphthalein‐based PAEK (PEK‐C), fluorene‐based PAEK (BFEK) and phthalazinone‐based PAEK (DPEK) not containing a carbazole unit, these polymers presented a 30–50 °C increase in T_g. Meanwhile, PAEKs prepared from N‐ethylcarbazole difluoroketone showed good solubility in ordinary organic solvents, and all polymers exhibited excellent resistance to hydrochloric acid (36.5 wt%) and sodium hydroxide (50 wt%) solutions. In particular, phthalazinone‐based PAEK bearing N‐ethylcarbazole afforded simultaneously a T_g of 301 °C with good solubility. Tensile tests of films showed that these polymers have desirable mechanical properties. The carbazole‐based difluoroketones play an important role in preparing soluble PAEKs with high T_g by coordinating the relationship between chain rigidity resulting from the carbazole unit and chain distance from the side alkyl. © 2014 Society of Chemical Industry     

Syntheses and properties of polyimides derived from diamines containing 2,5‐disubstituted pyridine group

A series of novel homo‐ and copolyimides containing pyridine units were prepared from the heteroaromatic diamines, 2,5‐bis (4‐aminophenyl) pyridine and 2‐(4‐aminophenyl)‐5‐aminopyridine, with pyromelltic dianhydride (PMDA), and 3,3′, 4,4′‐biphenyl tertracarboxylic dianhydride (BPDA) via a conventional two‐step thermal imidizaton method. The poly(amic acid) precursors have inherent viscosities of 1.60–9.64 dL/g (c = 0.5 g/dL in DMAC, 30°C) and all of them can be cast and thermally converted into flexible and tough polyimide films. All of the polyimides show excellent thermal stability and mechanical properties. The polyimides have 10% weight loss temperature in the range of 548–598°C in air. The glass transition temperatures of the PMDA‐based samples are in the range of 395–438°C, while the BPDA‐based polyimides show two glass transition temperatures (T_g1 and T_g2), ranging from 268 to 353°C and from 395 to 418°C, respectively. The flexible films possess tensile modulus in the range of 3.42–6.39 GPa, strength in the range of 112–363 MPa and an elongation at break in the range of 1.2–69%. The strong reflection peaks in the wide‐angle X‐ray diffraction patterns indicate that the polyimides have a high packing density and crystallinity. The polymer films are insoluble in common organic solvents exhibiting high chemical resistance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1844–1851, 2006     

Polyimides 6: Synthesis,characterization, and comparison of properties of novel fluorinated poly(ether imides)

Five new poly(ether imides) have been prepared on reaction with oxydiphthalic anhydride (ODA) with five different diamines: 1,4‐bis(p‐aminophenoxy‐2′‐trifluoromethyl benzyl) benzene, 4,4′‐bis(p‐aminophenoxy‐2′‐trifluoromethyl benzyl) benzene, 1,3‐bis(p‐aminophenoxy‐2′‐trifluoromethyl benzyl) benzene, 2,6‐bis(p‐aminophenoxy‐2′‐trifluoromethyl benzyl) pyridine, and 2,5‐bis(p‐aminophenoxy‐2′‐trifluoromethyl benzyl) thiophene. Synthesized polymers showed good solubility in different organic solvents. The polyimide films have low water absorption of 0.3–0.7%, low dielectric constants of 2.82–3.19 at 1 MHz, and high optical transparency at 500 nm (>73%). These polyimides showed very high thermal stability with decomposition temperatures (5% weight loss) up to 531°C in air and good isothermal stability; only 0.4% weight loss occurred at 315°C after 5 h. Transparent thin films of these polyimides exhibited tensile strength up to 147 MPa, a modulus of elasticity up to 2.51 GPa and elongation at break up to 30% depending upon the repeating unit structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 821–832, 2004     

Soluble N‐substituted poly(benzimidazole imide)s via C−N coupling reaction

Novel heat‐resistant N‐substituted poly(benzimidazole imide)s (PBIIs) with good solubility were synthesized via a C ? N coupling reaction. A model reaction was carried out to assist in determining the optimal reaction conditions for the polymerization and to elucidate the chemical structures of the polymers. The structures of the resulting polymers were characterized by means of Fourier transform infrared and elemental analysis; the results showed good agreement with the proposed structures. The resulting PBIIs exhibited high glass transition temperatures (T_g > 290 ^oC) and good thermostability (T_5% > 440 ^oC). The thermal behavior in air of the PBII polymers suggests that they can be considered as a new class of high performance polyimides. © 2016 Society of Chemical Industry     

Synthesis and characterization of novel polyimides derived from 2‐amino‐5‐(4‐aminophenyl)‐thiazole

A new kind of aromatic unsymmetrical diamine monomer containing thiazole ring, 2‐amino‐5‐(4‐aminophenyl)‐thiazole (AAPT), was synthesized. A series of novel polyimides were prepared by polycondensation of AAPT with various aromatic dianhydrides by one‐step polyimidation process. The synthesized polyimides had inherent viscosity values of 0.36–0.69 dL/g and were easily dissolved in highly dipolar solvents. Meanwhile, strong and flexible polyimide films were obtained, which have good thermal and thermo‐oxidative stability with the glass transition temperatures (T_g) of 276.7–346.1°C, the temperature at 5% weight loss of 451–492°C in nitrogen and 422–440°C in air, as well as have outstanding mechanical properties with the tensile strengths of 94–122 MPa, elongations at breakage of 5–18%. These films also had dielectric constants of 3.12–3.38 at 10 MHz. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of polyimides from 9,10-diphenoxy-1,2,3,4,5,6,7,8-octahydro-2,3,6,7-anthracenetetra-carboxylic 2,3:6,7-dianhydride

Summary A new dianhydride containing phenoxy groups and alicyclic unit was prepared by a bis-Diels-Alder reaction of 1,4-diphenoxy-2,3,5,6-tetrakis(bromomethyl)benzene with maleic anhydride, and polymerized with various aromatic diamines in one step at high temperature in NMP. All the polymers had good solubility toward polar solvents and their inherent viscosities were in the range of 0.31∼0.53dL/g. Polyimides properties were investigated and discussed in terms of the chain structures resulting from the incorporation of different diamines. All the polyimides were thermostable up to 475°C with 10% weight loss and in DSC thermograms the polymers exhibited T _gs between 249 and 317°C. Received: 29 January 2001/Revised version: 25 April 2001/Accepted: 27 April 2001