Synthesis and characterization of novel polyaspartimides derived from 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl and various diamines

A novel bismaleimide, 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl, containing noncoplanar 2,2′‐dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2′‐dimethyl‐4,4′‐bis(4‐aminophenoxy)biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m‐cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymers were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X‐ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g⁻¹ in concentration of 1.0 g dL⁻¹ of N,N‐dimethylformamide. All polymers are soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethylsulfoxide, pyridine, m‐cresol, and tetrahydrofuran. The polymers, except PASI‐4, had moderate glass transition temperature in the range of 188°–226°C and good thermo‐oxidative stability, losing 10% mass in the range of 375°–426°C in air and 357°–415°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 279–286, 1999     

Preparation and properties of polyimides based on bis[3,5‐dimethyl‐4‐(4‐aminophenoxy)phenyl]methane

A series of polyimide (PI) thin films were synthesized based on bis[3,5‐dimethyl‐4‐(4‐aminophenoxy)phenyl]methane and conventional aromatic dianhydrides. The structures and properties of the thin films were measured with Fourier transform infrared, NMR, thermogravimetric analysis, dynamic mechanical analysis, and impedance analysis. The PI films exhibited glass‐transition temperatures in the range of 211–300°C and possessed initial thermal decomposition temperature reaching up to 457–482°C in air and 461–473°C in nitrogen. Some PI films had high solubility in organic solvents such as 1‐methyl‐2‐pyrrolidinone, N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethyl sulfoxide, m‐cresol, tetrahydrofuran, and CHCl₃. The mechanical properties of these films were also examined. The dielectric constants of the films were in the range of 2.8–3.3 at 25°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1265–1270, 2007     

High‐optical transparency and low‐dielectric constant of new organosoluble polyamides containing trifluoromethyl and xanthene groups

A series of fluorinated polyamides was prepared directly by low‐temperature polycondensation of a new cardo diacid chloride, 9,9‐bis[4‐(4‐chloroformylphenoxy)phenyl]xanthene (BCPX), with various diamines containing trifluoromethyl substituents in N,N‐dimethylacetamide (DMAc). Almost all polyamides showed excellent solubility in amide‐type solvents such as DMAc and could also be dissolved in pyridine, m‐cresol, and tetrahydrofuran. These polymers had inherent viscosities between 0.77 and 1.31 dL g^?1, and their weight‐average molecular weights and number‐average molecular weights were in the range of 69,000–102,000 and 41,000–59,000, respectively. The resulting polymers showed glass transition temperatures between 240–258°C and 10% weight loss temperatures ranging from 484°C to 517°C and 410°C to 456°C in nitrogen and air, respectively, and char yields at 800°C in nitrogen higher than 55%. All polymers were amorphous and could be cast into transparent, light‐colored, and flexible films with tensile strengths of 81–100 MPa, elongations at break of 8–12%, and tensile modulus of 1.6–2.1 GPa. These polymers had low‐dielectric constants of 3.34–3.65 (100 kHz), low‐moisture absorption in the range of 0.76–1.91%, and high transparency with an ultraviolet–visible absorption cut‐off wavelength in the 322–340 nm range. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

Synthesis and characterization of new aromatic polyesters containing pendent naphthyl units

Two bisphenols, viz., 4,4′‐[1‐(2‐naphthalenyl)ethylidene]bisphenol and 4,4′‐[1‐(2‐naphthalenyl) ethylidene]bis‐3‐methylphenol were prepared by condensation of commercially available 2‐acetonaphthanone with phenol and o‐cresol, respectively. A series of new aromatic polyesters containing pendent naphthyl units was synthesized by phase‐transfer‐catalyzed interfacial polycondensation of these bisphenols with isophthaloyl chloride, terephthaloyl chloride, and a mixture of isophthaloyl chloride/terephthaloyl chloride (50 : 50 mol %). Inherent viscosities of polyesters were in the range 0.83–1.76 dL g⁻¹, while number average molecular weights (M_n) were in the range 61,000–235,000 g mol⁻¹. Polyesters were readily soluble in organic solvents such as dichloromethane, chloroform, tetrahydrofuran, m‐cresol, pyridine, N,N‐dimethylformamide, N,N‐dimethylacetamide, and 1‐methyl‐2‐pyrrolidinone at room temperature. Tough, transparent, and flexible films were cast from a solution of polyesters in chloroform. X‐Ray diffraction measurements displayed a broad halo at 2θ ≅ 19° indicating the amorphous nature of polyesters. Glass transition temperatures of polyesters were in the range 209–259°C. The temperature at 10% weight loss (T₁₀), determined by TGA in nitrogen atmosphere, of polyesters was in the range 435–500°C indicating their good thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Organosoluble,low‐dielectric‐constant fluorinated polyimides based on 9,9‐bis[4‐(4‐amino‐2‐trifluoromethyl‐ phenoxy)phenyl]xanthene

A new trifluoromethylated bis(ether amine) monomer, 9,9‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]xanthene (BATFPX), was prepared through the nucleophilic aromatic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel fluorinated polyimides were synthesized from BATFPX with various commercially available aromatic tetracarboxylic dianhydrides by one‐step polycondensation in m‐cresol. The resulting polyimides were readily soluble in many organic solvents such as N,N‐dimethylacetamide and tetrahydrofuran, and afforded transparent, flexible and strong films with low moisture absorption (0.28–0.51%), low dielectric constant (2.85–3.26 at 1 MHz) and good optical transparency with UV‐visible absorption cut‐off wavelengths at 352–410 nm. All the polyimides were amorphous and exhibited high thermal stability, with glass transition temperatures of 282–330 °C, 5% weight loss temperatures above 520 °C in nitrogen or air and char yields higher than 55% at 800 °C in nitrogen. Also, these polyimides had good mechanical properties with tensile strengths of 93–118 MPa, elongations at break of 9–16% and initial moduli of 2.07–2.58 GPa. Copyright © 2011 Society of Chemical Industry     

Polynaphthimidazoles prepared from naphthalene dicarboxylic acid and their properties

Phosphorus pentoxide/methanesulphonic acid (PPMA) was used as both solvent and condensing agent for the preparation of polynaphthimidazoles (PNIs) through direct polycondensation. The reactions of 2,6-naphthalene dicarboxylic acid and dimethyl 2,6-naphthalene dicarboxylate with tetramine monomer were studied with varying concentration of monomer, reaction temperature and reaction time in order to obtain high-molecular-weight polymer with high conversion. The properties, including solvent resistance, thermal properties and film casting, of synthesized polymers were also investigated. It was found that, using PPMA as both solvent and condensing agent, PNIs can be prepared successfully with high molecular weight by direct polycondensation of 2,6-naphthalene dicarboxylic acid or its derivatives with tetramine. The PNIs had inherent viscosities in the range 0.94–2.38 dl/g (in conc. H₂SO₄ at 30°C); however, polymers synthesized from isophthalic and terephthalic acids with tetramine had inherent viscosities of only 0.56dl/g and 0.48dl/g, respectively, with low conversions under similar reaction conditions. The glass transition temperature of the PNI 1 was 403°C. Thermal analysis indicates that these PNIs have excellent thermal stability, and the 10 wt% loss temperatures were recorded in the range 588–648°C in nitrogen gas, 533–580°C in air. The chemical stability and mechanical properties of films are also outstanding.     

Synthesis and characterization of polyetherimides containing multiple ether linkages and pendent pentadecyl chains

4‐(4‐(4‐(4‐Aminophenoxy)‐2‐pentadecylphenoxy)phenoxy)aniline (APPPA) was synthesized starting from cashew nut shell liquid‐derived bisphenol, i.e. 4‐(4‐hydroxyphenoxy)‐3‐pentadecylphenol, by nucleophilic substitution reaction with 4‐chloronitrobenzene followed by reduction of the formed 4‐(4‐nitrophenoxy)‐1‐(4‐(4‐nitrophenoxy)phenoxy)‐2‐pentadecylbenzene. Three new polyetherimides containing multiple ether linkages and pendent pentadecyl chains were synthesized by one‐step high‐temperature solution polycondensation of APPPA in m‐cresol with three aromatic dianhydrides, i.e. 3,3′,4,4′‐oxydiphthalic anhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride. Inherent viscosities and number‐average molecular weights of the polyetherimides were in the ranges 0.66–0.70 dL g^?1 and 17 100–29 700 g mol^?1 (gel permeation chromatography, polystyrene standards), respectively, indicating the formation of reasonably high molecular weight polymers. The polyetherimides were soluble in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, m‐cresol, N,N‐dimethylformamide, N,N‐dimethylacetamide, N‐methylpyrrolidone and dimethylsulfoxide, and could be cast into transparent, flexible and tough films from their solutions in chloroform. The polyetherimides exhibited glass transition temperatures (T_g) in the range 113–131 °C. The lowering of T_g could be attributed to the combined influence of flexibilizing ether linkages and pentadecyl chains which act as ‘packing‐disruptive’ groups. The temperature at 10% weight loss (T₁₀), determined from thermogravimetric analysis in nitrogen atmosphere, was in the range 460–470 °C demonstrating good thermal stability. The virtues of solubility and large gap between T_g and T₁₀ mean that the polyetherimides containing pendent pentadecyl chains have possibilities for both solution as well as melt processability. © 2015 Society of Chemical Industry     

Synthesis and properties of novel organosoluble aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkages

Several novel aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkages with inherent viscosities of 0.62–0.65 dL/g were prepared from 2‐methyldiphenylether and 3‐methyldiphenylether with 4,4′‐bis(4‐chloroformylphenoxy)diphenylsulfone and 4,4′‐bis (3‐chloroformylphenoxy)diphenylsulfone by electrophilic Friedel–Crafts acylation in the presence of N,N‐dimethylformamide with anhydrous AlCl₃ as a catalyst in 1,2‐dichloroethane. These polymers, having weight‐average molecular weights in the range of 57,000–71,000, were all amorphous and showed high glass‐transition temperatures ranging from 160.5 to 167°C, excellent thermal stability at temperatures over 450°C in air or nitrogen, high char yields of 52–57% in nitrogen, and good solubility in CHCl₃ and polar solvents such as N,N‐dimethylformamide, dimethyl sulfoxide, and N‐methyl‐2‐pyrrolidone at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 84.6–90.4 MPa, Young's moduli of 2.33–2.71 GPa, and elongations at break of 26.1–27.4%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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 properties of some novel,soluble and light‐coloured,aromatic poly(amide–imide) copolymers

A new type of tetraimide‐dicarboxylic acid (I) was synthesized starting from the ring‐opening addition of m‐aminobenzoic acid (m‐ABA), 4,4′‐oxydiphthalic anhydride (ODPA) and 4,4′‐methylenedianiline (MDA) at a 2:2:1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of soluble and light‐coloured poly(amide–imide–imide)s (III_a–j) was prepared by triphenyl phosphite‐activated polycondensation from the tetraimide‐diacid I with various aromatic diamines (II_a–j). All films cast from DMAc had cutoff wavelengths shorter than 400 nm (376–393 nm) and had b* values between 20.46 and 40.67; these polymers were much lighter in colour than those of the corresponding trimellitimide series. All polymers were readily soluble in a variety of organic solvents such as NMP, N,N‐dimethylacetamide, dimethyl sulfoxide, and even in the less polar m‐cresol and pyridine. Compared with those of corresponding ODPA–MDA polyimide, the solubilities of poly(amide–imide–imide)s III_a–j were greatly improved. Polymers III_a–j afforded tough, transparent, and flexible films, which had tensile strengths ranging from 82 to 105 MPa, elongations at break from 8 to 14%, and initial moduli from 2.0 to 2.2 GPa. The glass transition temperature of polymers were recorded at 255–288 °C. They had 10% weight loss at a temperature above 540 °C and left more than 60% residue even at 800 °C in nitrogen. © 2002 Society of Chemical Industry     

Synthesis of new soluble aromatic poly(amide imide)s from unsymmetrical extended diamine containing phthalazinone moiety

The preparation of a new unsymmetrical kink non‐coplanar heterocyclic diamine, 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(3‐phenyl‐4‐aminophenoxy)phenyl]‐(2H)phthalazin‐1‐one (3), from a readily available unsymmetrical phthalazinone bisphenol‐like (1) was described. The diamine can be directly polymerized with various aromatic bis(trimellitimide)s (4a–e) by using triphenyl phosphite and pyridine as condensing agents to give a series of new aromatic poly(amide imides) (5a–e) containing the kink non‐coplanar phthalazinone heterocyclic units with inherent viscosities of 0.57–1.06 dL/g. The polymers were readily soluble in a variety of solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethylsulfoxide, N‐methyl‐2‐pyrrolidinone, and even in pyridine and m‐cresol and could be cast to form flexible and tough films. The glass transition temperatures were in the range of 315–340°C, and the temperatures for 5% weight loss in nitrogen were in the range of 487–512°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1516–1520, 2004     

Novel organosoluble poly(amide‐imide‐imide)s synthesized from new tetraimide‐dicarboxylic acid by condensation with 4,4′‐oxydiphthalic anhydride, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene,trimellitic anhydride,and various aromatic diamines

A new monomer of tetraimide‐dicarboxylic acid (IV) was synthesized by starting from ring‐opening addition of 4,4′‐oxydiphthalic anhydride, trimellitic anhydride, and 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene at a 1:2:2 molar ratio in N‐methyl‐2‐pyrrolidone (NMP). From this new monomer, a series of novel organosoluble poly(amide‐imide‐imide)s with inherent viscosities of 0.7–0.96 dL/g were prepared by triphenyl phosphite activated polycondensation from the tetraimide‐diacid with various aromatic diamines. All synthesized polymers were readily soluble in a variety of organic solvents such as NMP and N,N‐dimethylacetamide, and most of them were soluble even in less polar m‐cresol and pyridine. These polymers afforded tough, transparent, and flexible films with tensile strengths ranging from 99 to 125 MPa, elongations at break from 12 to 19%, and initial moduli from 1.6 to 2.4 GPa. The thermal properties and stability were also good with glass‐transition temperatures of 236–276°C and thermogravimetric analysis 10 wt % loss temperatures of 504–559°C in nitrogen and 499–544°C in air. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2854–2864, 2006     

Synthesis and characterization of polyesters based on 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane

Aromatic polyesters are of considerable interest because of their excellent mechanical properties, chemical resistance and thermal stability. However, most aromatic polyesters are difficult to process due to their high glass transition temperatures coupled with their insolubility in common organic solvents. The present article describes a series of organosoluble polyesters and copolyesters based on 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane. A series of new aromatic polyesters containing pendant pentadecyl chains was synthesized by interfacial polycondensation of 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane with terephthalic acid chloride (TPC), isophthalic acid chloride (IPC) and a mixture of TPC and IPC. A series of copolyesters was synthesized from 4,4′‐isopropylidenediphenol with TPC by incorporating 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane as a comonomer. Inherent viscosities of the polyesters and copolyesters were in the range 0.72–1.65 dL g^?1 and number‐average molecular weights were in the range 18 170–87 220. The polyesters and copolyesters containing pendant pentadecyl chains dissolved readily in organic solvents such as chloroform, dichloromethane, pyridine and m‐cresol and could be cast into transparent, flexible and apparently tough films. Wide‐angle X‐ray diffraction data revealed the amorphous nature of the polyesters and copolyesters. The formation of loosely developed layered structure was observed due to the packing of pendant pentadecyl chains. The temperature at 10% weight loss, determined using thermogravimetric analysis in nitrogen atmosphere, of the polyesters and copolyesters containing pendant pentadecyl chains was in the range 400–460 °C. The polyesters and copolyesters exhibited glass transition temperatures in the range 63–82 °C and 177–183 °C, respectively. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of 4,4′‐diaminodiphenyl methane‐based benzoxazines and their polymers

A series of diamine‐based benzoxazine precursors have been prepared using 4,4′‐diaminodiphenyl methane, formaldehyde, and different phenol derivatives including phenol, p‐cresol, and 2‐naphthol. Their chemical structures were identified by FTIR, ¹H NMR, and elemental analysis. The curing reactions of those precursors were monitored by FTIR and DSC. The obtained materials exhibited higher glass transition temperature and char yields than the corresponding bisphenol‐A based polybenzoxazines. The polybenzoxazine prepared from phenol showed the highest char yields of 65% and thermal stability with 5 and 10% weight‐loss temperatures at 346 and 432°C, respectively. The polybenzoxazine prepared from 2‐naphthol exhibited the highest glass transition temperature at 244°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of novel soluble pyridine‐containing polyimides based on 4‐phenyl‐2,6‐bis[4‐(4‐aminophenoxy)phenyl]‐pyridine and various aromatic dianhydrides

A new kind of pyridine‐containing aromatic diamine monomer, 4‐phenyl‐2,6‐bis[4‐(4‐aminophenoxy)phenyl]‐pyridine (PAPP), was successfully synthesized by a modified chichibabin reaction of benzaldehyde and a substituted acetophenone, 4‐(4‐nitrophenoxy)‐acetophenone (NPAP), followed by a reduction of the resulting dinitro compound 4‐phenyl‐2,6‐bis[4‐(4‐nitrophenoxy)phenyl]‐pyridine (PNPP) with Pd/C and hydrazine monohydrate. The aromatic diamine was employed to synthesize a series of new pyridine‐containing polyimides by polycondensation with various aromatic dianhydrides in N‐methy‐2‐pyrrolidone (NMP) via the conventional two‐step method, 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 0.79–1.13 dL/g, and most of them were soluble in common organic solvents such as N,N‐dimethylacetamide (DMAc), NMP, and tetrahydrofuran (THF), etc. Meanwhile, strong and flexible polyimide films were obtained, which had good thermal stability, with the glass transition temperatures (T_g) of 268–338°C and the temperature at 5% weight loss of 521–548°C in air atmosphere, as well as outstanding mechanical properties with tensile strengths of 89.2–112.1 MPa and elongations at break of 9.5–15.4%. The polyimides also were found to possess low dielectric constants ranging from 2.53 to 3.11. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 212–219, 2007     

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     

Preparation,characterization, and polymerization of novel maleimidobenzoxazine containing carboxylic moiety and its cocuring behaviors with epoxy resin

A novel benzoxazine containing maleimide and carboxylic moieties, 1‐[3‐(4‐carboxylphenyl)‐3,4‐dihydro‐2H‐benzo[e][1,3]‐oxazin‐6‐yl]maleimide (Mal‐Bz‐Co), was synthesized and the structure was identified by ¹H‐NMR and FTIR. Mal‐Bz‐Co exhibited good solubility in common organic solvents. The cure behavior of Mal‐Bz‐Co and cocure behavior of Mal‐Bz‐Co with o‐cresol formaldehyde epoxy resin were investigated by differential scanning calorimetry. Results indicated that Mal‐Bz‐Co showed a single curing exothermic peak at about 238.3°C. However, the maximum curing temperature (T_p) decreased to 146.1°C when Mal‐Bz‐Co cocured with o‐cresol formaldehyde epoxy resin in the molar ratio of 1 : 1. The T_p was about 92°C lower than that of Mal‐Bz‐Co. Thermogravimetric analysis showed that high‐decomposition temperature and char yield were observed for the cured resins of Mal‐Bz‐Co and Mal‐Bz‐Co/o‐CFER. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Aromatic polyimides from m‐phenylene diamines containing pendant groups: Synthesis and characterization

Two diamine monomers, 4‐[4‐(1‐methyl‐1‐phenylethyl)phenoxy]‐1,3‐diamino benzene and 4‐{4‐[(4‐methylphenyl)sulfonyl]phenoxy}‐1,3‐diamino benzene, were synthesized, and both diamines were polycondensed with three commercial dianhydrides to obtain aromatic polyimides containing pendant groups. The polyimides were characterized by solubility tests, viscosity measurements, IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy, X‐ray diffraction studies, and thermogravimetric analysis. The polyimides had inherent viscosities of 0.33–0.58 dL/g in m‐cresol at 30 ± 0.1°C. All the polyimides were amorphous and were soluble in solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, N,N‐dimethylformamide, and m‐cresol. Thermogravimetric analysis of the polyimides indicated no weight loss below 410°C under a nitrogen atmosphere. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1377–1384, 2005     

Synthesis and characterization of novel thermally stable and optically active poly(amide‐imide)s derived from N,N′‐(4,4′‐diphthaloyl)‐bis‐L‐leucine diacid and aromatic diamines

A new diacid containing optically active functional groups, N,N′‐(4,4′‐diphthaloyl)‐bis‐L ‐leucine diacid ( 3 ), was synthesized and used in a preparation of a series of poly(amide‐imide)s (PAIs) by direct polycondensation with various aromatic diamines in N‐methyl‐2‐pyrrolidinone (NMP). All polymers derived from diacid ( 3 ) were highly organosoluble in the solvents like N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, γ‐butyrolactone, cyclohexanone, and chloroform at room temperature or upon heating. Inherent viscosities of the PAIs were found to range between 0.34 and 0.61·dL g^?1. All the PAIs afforded flexible and tough films. The glass‐transition temperatures of these PAIs were recorded between 212 and 237°C by differential scanning calorimetry, and the 10% weight loss temperatures were ranging from 372 to 393°C and 336–372°C under nitrogen and air, respectively. The polyimide films had a tensile strength in the range of 63–88 MPa and a tensile modulus in the range of 1.2–1.7 GPa. Optically active PAIs exhibited specific rotations in the range of ?10.58° to ?38.70°. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007