Synthesis, characterization, and crosslinking of soluble cyano-containing poly(arylene ether)s bearing phthalazinone moiety

A novel series of phthalazinone-based poly(arylene ether nitrile)s bearing terminal cyano groups via N-C linkages (PPEN-DCs) were synthesized by a simple solution polycondensation of 4-(4-hydroxylphenyl)(2H)-phthalazin-1-one (HPPZ) with calculated 2,6-difluorobenzonitrile (DFBN), followed by the termination of 4-chlorobenzonitrile (CBN). The M_ns of oligomeric PPEN-DCs, which are in the range of 1600-6200, can be well-controlled by adjusting reactant ratio. The incorporation of phthalazinone into the polymer chain results in an improvement in the solubility and glass transition temperatures (T_gs). The amorphous PPEN-DCs were thermally crosslinked to afford insoluble products in the presence of terephthalonitrile and zinc chloride. The pendant cyano groups in the polymer chain hardly undergo any crosslinking or cyclization, while the terminal cyano groups with nitrogen-bridged phthalazinone in the para-substitution are much more reactive in s-triazine forming reaction and effectively promote certain crosslinking under normal pressure. T_gs of the oligomers, which range from 245 to 269 °C, could be further increased at least by 94 °C upon thermal curing. The crosslinked samples exhibit excellent thermal stability and absorb less than 2.7 wt% water after exposure to an aqueous environment for extended periods. This kind of cyano-terminated poly(arylene ether nitrile)s may be a good candidate as matrix resins for high-performance polymeric materials.     

Soluble rigid rod-like polyimides and polyamides containing curable pendent groups

Soluble rod-like aromatic polyimides and polyamides containing curable pendent groups were synthesized. The polyimides (PIEANs) and polyamides (PAEANs) containing pendent enaminonitrile groups showed good thermal stability, and underwent curing reactions without the emission of volatile by-products above 300 °C to stable materials which were not soluble in any organic solvents. However, the polyimides (PIEONs) and polyamides (PAEONs) containing pendent enoxynitrile groups started to decompose around 300 °C, because of the instability of enoxynitrile groups. PAEONs underwent curing reactions around 420 °C in spite of the initial decomposition, but PIEONs exhibited only thermal degradation process. Thermal analyses of these polymers and the corresponding model compounds revealed that the curing of enaminonitrile groups proceeded via intermolecular crosslinking as well as intramolecular cyclization, while the enoxynitrile groups, known to undergo self-curing reaction, could not be cured by itself, and a reactive amine group was essential for the curing of the enoxynitrile groups.     

Synthesis and study of the effect of carboxyvinyl group position on the properties of polyamides. Crosslinked polymers

Several aromatic polyamides containing carboxyvinyl bonds in the main chain were synthesized by self-condensation from β-(2-,3-,4-aminophenyl)propenoic acid using the phosphorylation method. In addition, aromatic polyamides containing carboxyalkyl bonds in the backbone were synthesized under the same conditions for comparative purposes (model polyamides) and used as pattern. The model polyamides were synthesized from 3-,4-aminophenyl acetic acid and β-(3-aminophenyl)propanoic acid. Polymers were characterized by UV–vis, FT-IR and ¹H-NMR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and inherent-viscosity measurement. The effect of the carboxyvinyl group position in the aromatic ring was correlated to polyamides properties. Thereby, solubility, thermal stability, viscosities, optical properties, and polymers crosslinking were studied. Some polyamides were soluble in polar solvents and inorganic acids. Upon thermal curing crosslinked polymers were obtained. The thermal stability and crosslinking of polyamides were evaluated with respect to position of carboxyvinyl in the aromatic ring. The crosslinked polymers exhibited improved thermal stability.     

New soluble polyamides and polyimides containing polar functional groups: pendent pyrazole rings with amino and cyano groups

A series of aromatic polyamides and polyimides containing pendent pyrazole rings with amino and cyano groups were prepared from a new monomer, 1-(2,4-diaminophenyl)-3-phenyl-4-cyano-5-aminopyrazole, which was prepared from (chloromethylene)propanedinitrile and 2,4-dinitrophenyl hydrazine with two steps. In addition, model compounds were synthesized and characterized by elemental analyses, Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopy. The amino and cyano groups on the pyrazole ring were not affected during the polymerization process. The synthesized polymers, with intrinsic viscosities of 0.33–0.53 dL/g, were soluble in various organic solvents. They showed no T_g values before degradation, and the 5% weight loss temperature of the polyamides and the polyimides occurred at approximately 420 and 470 °C, respectively. They also underwent no thermal transitions, such as degradation or crosslinking, up to 440 °C in spite of the presence of pendent amino and cyano groups.     

New soluble triphenylamine-based amorphous aromatic polyamides for high performance blue-emitting hole-transporting and anodically electrochromic materials

A newly 4-methoxy-substituted triphenylamine-containing aromatic diacid monomer, 4,4′-dicarboxy-4″-methoxytriphenylamine 2, with blue light (454 nm) fluorescence quantum efficiency 45% was successfully synthesized by the sodium hydride-mediated condensation of 4-methoxyaniline with 4-fluorobenzonitrile, followed by alkaline hydrolysis of the intermediate dicyano compound. A series of novel aromatic polyamides having strong fluorescence emissions in the blue region with high quantum yields up to 40% and one reversible oxidation redox couples at 1.08 V vs. Ag/AgCl in acetonitrile solution have been synthesized and characterized. They exhibited good thermal stability with 10% weight-loss temperatures above 460 °C under a nitrogen atmosphere with relatively high glass-transition temperatures (267-307 °C). All obtained polyamides revealed excellent stability of electrochromic characteristics, changing color from original pale yellowish to blue.     

Soluble wholly aromatic polyamides containing unsymmetrical pyridyl ether linkages

Wholly aromatic polyamides were synthesized from the amidation reaction between unsymmetrical diamine containing a pyridyl ether linkage and aromatic dicarboxylic acid chloride. The resulting polyamides containing pyridyl ether linkages showed high thermal stability (T_d5=467 °C) and enhanced solubility in organic solvents compared with the analogous polyamides having phenyl ether linkages. Substitution of just a single atom in a repeating unit was effective to disrupt the strong inter-chain interaction of parent aramid polymers.     

Synthesis and properties of lyotropic liquid crystalline copolyamides containing phthalazinone moiety and ether linkages

A series of aromatic copolyamides containing phthalazinone moiety and ether linkages were prepared from 1,2-dihydro-2-(4-aminophenyl)-4-[4-(4-(aminophenoxyl)phenyl)](2H)phthalazin-1-one (DHPZ-DA), p-phenylenediamine (PPD), 4,4′-diaminodiphenylether (DAPE) and terephthaloyl dichloride (TPC) by low temperature solution polycondensation. The copolyamides had relatively high inherent viscosities, ranging from 1.86 to 5.30 dl/g. The copolyamides showed T_g values between 297 and 351 °C. Solubility of these copolyamides was improved in NMP, DMAc, NMP (1 wt% LiCl) and DMAc (1 wt% LiCl) by introducing phthalazinone moiety and ether linkages into the main chain. And they had good thermal stability, associated with 5 and 10% weight loss temperatures in the range of 480-516 and 501-532 °C in nitrogen, respectively. WAXD measures indicated these copolyamides were semicrystalline in nature. Some of these copolyamides exhibited lyotropic liquid crystalline behavior in concentrated H₂SO₄, NMP (1 wt% LiCl), and even in NMP solutions, as evidenced by polarizing light microscopy.     

Synthesis and properties of a series of cyanate resins based on phenolphthalein and its derivatives

Two new cyanate monomers simultaneously containing phthalide group and different alkyl substituents on the phenylene rings (o-PCY and t-PCY) and the Phenolphthalein-based cyanate (p-PCY) were successfully synthesized by the reaction of o-cresolphthalein, thymolphthalein and phenolphthalein with cyanogen bromide in the presence of triethylamine, respectively. Their chemical structures were confirmed by means of FTIR, NMR and elemental analysis methods. All these monomers owned sufficiently wide processing temperature windows and could be readily cured without the addition of catalyst. The dynamic mechanical analysis (DMA) results showed that the introduction of phthalide structure into the polycyanurate network could effectively improve the thermal properties of the cyanate ester (CE) resin. Especially, the T_g values of the fully cured p-PCY, o-PCY and t-PCY resins are 362 °C, 328 °C and 298 °C, respectively, which are apparently higher than that of most bisphenol-based cyanate resins reported in the literatures (190-290 °C). The thermal and thermo-oxidative properties as well as the water absorptions of the cured products were compared with those of the bisphenol A cyanate resin (BACY), and the structure-property relationships were explained according to the chemical structures and crosslinking densities of the formed polymer networks. The high-T_g thermosetting materials thus prepared are expected to expand the usage of CEs to areas where higher temperature requirements are encountered.     

Synthesis and characterization of novel soluble fluorinated aromatic polyamides derived from fluorinated isophthaloyl dichlorides and aromatic diamines

Two series of fluorinated aromatic polyamides derived from two novel monomers, 5-(4-trifluoromethylphenoxy)isophthaloyl dichloride (3FPC) and 5-(3,5-bistrifluoromethyl-phenoxy)isophthaloyl dichloride (6FPC) with various aromatic diamines were synthesized and characterized. Experimental results indicated that the fluorinated aromatic polyamides showed good solubility in many organic solvents. The solubility of the polyamides was affected by the trifluoromethyl substituents and the pendent phenoxy groups in the polymer backbone. The fluorinated polyamides have good thermal stability with the glass transition temperature of 206-285 °C, the temperature at 5% weight loss of 442-460 °C in nitrogen. The polyamide films also exhibited good mechanical properties and excellent electrical and dielectric properties. The fluorinated groups in the polymer backbone have played an important role in the improvement of electrical and dielectric performance of polymer.     

Preparation and properties of film materials of poly(aryl ether ketone)–based phthalonitrile resins

A series of poly(aryl ether ketone) polymers (m‐PAEK‐CN) containing phthalonitrile were synthesized by a direct solution polycondensation and characterized by Fourier‐transform infrared spectroscopy and hydrogen nuclear magnetic resonance. Thermal crosslinking of m‐PAEK‐CN, catalyzed by p‐BAPS, was then performed via heating their films up to 350^oC. Dynamic rheology results showed that the rate of diamine‐catalyzed crosslink reaction could be easily controlled by varying the content of cyano groups in the polymer. The uncured synthesized polymers had good solubility, whereas the cured ones became insoluble in common organic solvents. Spectra measurement demonstrated the trimerization reaction of terminal cyano groups to form triazine rings. The resulting cured samples had higher glass transition temperatures, better thermal, and thermo‐oxidative stability with high char yield than the uncured ones. Gel content measurements demonstrated that the cured polymers had high crosslinking density with significantly high gel content over 96.0%. Thermal mechanical analysis indicated that the cured phthalonitrile resins possessed excellent thermal mechanical properties and dimensional stability at increased temperatures. The tensile modulus and strength of the cured m‐PAEK‐CN increased up to 2101–2104 MPa and 96–100 MPa, respectively, which were about 21–23% and 32–56% higher than the uncured ones’. This kind of phthalonitrile resins may be used as a candidate for high‐performance polymeric film materials. POLYM. ENG. SCI., 55:2313–2321, 2015. © 2015 Society of Plastics Engineers     

Synthesis of novel bisphenol containing phthalazinone and azomethine moieties and thermal properties of cured diamine/bisphenol/DGEBA polymers

A novel bisphenol(1,2-dihydro-2-(4-((4-hydroxy)phenyliminomethylidene)phenyl)-4-(4-((4-(4-hydroxy)phenyliminomethylidene)phenoxy)phenyl)(2H)phthalazin-1-one, DPP) and a diamine(1,2-dihydro-2-(4-aminophenyl)-4-(4-(4-aminophenoxy)phenyl)(2H)phthalazin-1-one, DAP) were synthesized and characterized. The novel epoxy polymers containing phthalazinone and/or azomethine moieties were prepared by binary polymerization of DAP (or DPP) with diglycidyl ether of biphenyl A (DGEBA) and ternary polymerization of hybrid curing agents, DAP/DPP (DAP and DPP under different molar ratios) with DGEBA. The cure behaviors of these new epoxy systems were studied by dynamic differential scanning calorimeter (DSC) and Infrared (IR) scans. Especially, the activation energy of DAP/DGEBA calculated by Kissinger and Ozawa methods were 73.8 and 77.4 kJ/mol, respectively. For ternary epoxy system, it was found that hybrid curing agents of DAP/DPP exhibited significant associated effect on their reactivity towards the oxirane group. Glass transition temperatures (T_g's) of these new epoxy polymers were all above 150 °C from the results of DSC, and the initial thermal decomposition temperatures (T_d,5%'s) and integral procedure decomposition temperatures (IPDT's) of these new epoxy polymers are above 350 and 850 °C, respectively from results of thermogravimetric analyses (TGA). These results show that new epoxy polymers containing phthalazinone and/or azomethine moieties exhibited excellent thermal properties. Especially, thermal properties of the ternary epoxy polymers could be modified by changing the content of DAP and DPP. The linear relationships between char yield (Y_c,wt%) and the structural compositions of these new polymers (weight percentage of phthalazinone, azomethine and nitrogen, C/H weight ratio) were built.     

Synthesis and characterization of adamantane-containing poly(enaminonitriles)

The first aliphatic bis(chlorovinylidene cyanide) monomer, 1,3-bis(1-chloro-2,2-dicyanovinyl)adamantane, has been synthesized and polymerized with appropriate diamines to give adamantane-containing aromatic-aliphatic and all aliphatic poly(enaminonitriles) (PEANs) via vinylic nucleophilic substitution polymerization. The PEANs showed excellent solubility in polar aprotic solvents and good thermal stability (10% weight loss in air > 320 °C), despite the aliphatic contents of the polymers. Solution inherent viscosities of 0.23-0.90 dL/g were obtained.Three other new PEANs containing the adamantane-based cardo group were also synthesized via vinylic nucleophilic substitution polymerization from the adamanaine-containing cardo diamine 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane. The cardo PEANs showed better solubility in common organic solvents than the corresponding cardo polyamides. They also showed good thermal stabilities (10% weight loss in air > 339 °C) comparable to those of the corresponding cardo polyamides.     

Soluble aromatic polyamides bearing asymmetrical diaryl ether groups

A series of novel aromatic polyamides containing asymmetrical diaryl ether structure were synthesized by the phosphorylation polyamidation of 5-(4-aminophenoxy)-1-naphthylamine with various dicarboxylic acids. The polymers were obtained in high yields and moderately high inherent viscosities (0.74-1.36 dl/g). Except for one example, all the polyamides were amorphous and readily soluble in many organic solvents and could afford flexible and tough films via solution casting. The cast films exhibited good mechanical properties with tensile strengths of 90-128 MPa, elongations at break of 9-64%, and initial moduli of 2.08-3.08 GPa. Glass-transition temperatures ranged from 222 to 288 °C by DSC. Thermal stabilities by TGA for the polymer series ranged from 462 to 517 °C in air at the point of 10% weight loss. These polyamides displayed a lower crystallinity and better solubility and film-forming capability than the corresponding analogues derived from symmetrical 1,5-diaminonaphthalene and 1,5-bis(4-aminophenoxy)naphthalene.     

Synthesis,characterization, and properties of novel aromatic polyamides containing phthalazinone moiety

A unsymmetrical and kink non-coplanar heterocyclic dicarboxylic acid monomer, 4-[4-(4-carboxy phenoxy)-naphthyl]-2-(4-carboxyphenyl)phthalazin-1-one (3) was successfully synthesized with high purity and high yields. A series of novel polyamides containing phthalazinone were prepared from the newly synthesized dicarboxylic acid with various aromatic diamines by means of the phosphorylation polycondensation reaction. Molecular weights of the obtained polyamides were evaluated viscometrically, and the inherent viscosities (η_inh) measured were in the range 0.54–0.69 dL/g. These polyamides were amorphous and readily soluble in many organic solvents, such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimetheylformamide, dimethyl sulfoxide, pyridine, and m-cresol etc., and they could easily be solution-cast into transparent, flexible films with good mechanical properties, with tensile strength ranging from 63.9 to 81.6 MPa and elongation at break from 7.2 to 11.4%. These polymers still kept good thermal stability with high-glass transition temperatures in the range of 283–338 °C, and the decomposition temperature in nitrogen for a 10% weight-loss temperatures in excess of 490 °C, and char yield at 800 °C in nitrogen ranged from 56 to 63%. Furthermore, the polyamides films were essentially colorless; their cut-off wavelengths were between 365 and 379 nm.     

Preparation and characterization of carbon membranes made from poly(phthalazinone ether sulfone ketone)

Carbon membranes were prepared from a novel polymeric precursor of poly(phthalazinone ether sulfone ketone) (PPESK), of which the changes of microstructure and chemical compositions during pyrolysis from 500 °C to 950 °C were monitored by thermal gravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. It has been found that the weight loss of the PPESK precursor up to 800 °C is about 43.0 wt%. After the heat treatment, the typical chemical structure of the PPESK precursor disappears, at the same time a graphite-like structure with more aromatic rings is formed. The interlayer spacing (i.e., d value) decreases from 0.471 nm to 0.365 nm as the pyrolysis temperature increases. The gas permeation performance of carbon membranes has been tested using pure single gases including H₂, CO₂, O₂ and N₂. For the carbon membrane obtained by carbonizing the PPESK precursor at 800 °C, the maximum ideal permselectivities for H₂/N₂, CO₂/N₂ and O₂/N₂ gas pairs could reach 278.5, 213.8 and 27.5, respectively.     

Synthesis and properties of novel liquid ester-free reworkable cycloaliphatic diepoxides for electronic packaging application

Four novel liquid cycloaliphatic diepoxides, with two epoxycyclohexyl moieties linked via -O- (EpoI), -OCH₂CH₂O- (EpoII), -OCH (CH₃)CH₂O- (EpoIII), -OCH(CH₃)CH₂CH(CH₃)O- (EpoIV), respectively, and their diene precursors were synthesized and characterized. These diepoxides could be readily cured with hexahydro-4-methylphthalic anhydride (HMPA) using Iron (III) acetylacetonate as curing accelerator. The thermal and mechanical properties of cured products were examined by differential scanning calorimetry (DSC), thermal mechanical analysis (TMA) and dynamic mechanical analysis (DMA). The thermogravimetric analysis (TGA) data revealed that, the cured EpoI and EpoII had similar thermal decomposition onset temperature to the commercial ERL-4221™ (>300 °C), whereas the cured EopIII and EpoIV, having secondary or tertiary carbon-ether linkages, started to decompose at obviously lower temperature (around 220 °C), which just lay in the desired reworkability temperature range (200-300 °C). The higher glass transition temperature (>120 °C) and moderately low thermal decomposition temperature made EpoIII and EpolV suitable candidates for future reworkable flip chip electronic packaging application.     

High optical transparency, low dielectric constant and light color of novel organosoluble polyamides with bulky alicyclic pendent group

Novel optically transparent, low dielectric and highly organosoluble alicyclic polyamides derived from bulky alicyclic diamine containing trifluoromethyl group on either side, 1,1-bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl]-4-tert-butylcyclohexane (BTFAPBC), were prepared. The polyamides were obtained in almost quantitative yields and showed inherent viscosity values between 0.55 and 0.72 dL g⁻¹ in DMAc solution. Most of the polyamides showed excellent solubility in polar solvents such as N-methyl-2-pyrrolidinone (NMP), N,N′-dimethyl acetamide (DMAc), N,N′-dimethyl formamide (DMF), pyridine, cyclohexanone, γ-butyrolactone and chloroform. The cut-off wavelength for polyamides ranged from 350 to 388 nm. Polyamides with alicyclic tert-butylcyclohexyl cardo and trifluoromethyl substituents exhibited low dielectric constants ranging from 3.29 to 3.98 (at 100 Hz) compared with commercially available polyamides [Amodel^®, 4.2-5.7 at 100 Hz]. Polyamides showed glass transition temperatures in the range of 244-266 °C and possessed a coefficient of thermal expansion (CTE) of 60-75 ppm °C⁻¹. Thermogravimetric analysis data showed that the polyamides were stable up to 430 °C and the 10% weight loss temperature was found to be in the range of 437-466 °C in nitrogen atmosphere. The polyamide films had a tensile strength in the range of 66-103 MPa, elongation at break in the range of 5-8%, and tensile modulus in the range of 1.5-2.2 GPa. Due to their properties, the polyamides could be considered as engineering plastic and photoelectric materials.     

Synthesis and characterization of novel polyimides derived from 2-amino-5-[4-(4′-aminophenoxy)phenyl]-thiazole with some of dianhydride monomers

A new kind of aromatic unsymmetrical diamine monomer containing thiazole ring, 2-amino-5-[4-(4′-aminophenoxy)phenyl]-thiazole (APPT), was synthesized. A series of novel polyimides were prepared by polycondensation of APPT with various aromatic dianhydrides via one-step process. The resulting polyimides held inherent viscosities of 0.40-0.71 dL/g and were easily dissolved in strong dipolar solvents. Meanwhile, strong and flexible polyimide films were obtained, which had thermal stability with the glass transition temperatures (T_g) of 268.2-328.8 °C in nitrogen, the temperature at 5% weight loss of 452-507 °C in nitrogen and 422-458 °C in air, and the residue at 800 °C of 54.18-63.33% in nitrogen, as well as exhibited outstanding mechanical properties with the tensile strengths of 105.4-125.3 MPa, elongations at breakage of 6-13%. These films also held dielectric constants of 3.01-3.18 (10 MHz) and showed predominantly amorphous revealed by wide-angle X-ray diffraction measurements.     

Preparation and morphology distinguishing of novel ZnO ultrafine particle filled nanocomposites contain new poly(amide-imide) via ultrasonic process

New triptycene-containing polyamides were prepared from 1,4-bis(4-carboxyphenoxy)triptycene with aromatic diamines or from 1,4-bis(4-aminophenoxy)triptycene with aromatic dicarboxylic acids via the phosphorylation polyamidation reaction. These polyamides were essentially amorphous and showed a significantly increased solubility as compared with their analogs without the triptycene units. All the polyamides could be solution-cast into flexible and tough films. They also showed good thermal stability with glass transition temperatures of 252?C295?°C and 10?% weight loss temperatures higher than 540?°C. These polyamides are considered to be promising processable high-temperature polymeric materials.     

Synthesis and Characterization of Polyamides Based on s-Triazine Moiety

Seven polyamides containing s-triazine rings in the main chain were synthesized by high temperature polycondensation of 2-(β-naphthylamino)-4,6-bis(naphthoxy-3-carbonyl chloride)-s-triazine [NANCCT] with various aromatic diamines such as 4,4′-diaminodiphenyl [DADP], 4,4′-diaminodiphenylamide [DADPA], 4,4′-diaminodiphenylsulphone [DADPS], 4,4′-diaminodiphenylsulphonamide [DADPSA], 4,4′-diaminodiphenyl methane [DADPM], 2,4-diamino toluene [DAT] and p-phenylene diamine [PPDA]. All the polyamides were characterized by solubility tests, density measurements, viscosity measurements, IR spectra, NMR spectra, and thermogravimetric analysis. The polyamides had inherent viscosities in the range 0.88–1.16 g/dL in N,N′-dimethyl formamide at room temperature (30°C). All the polyamides showed good thermal stability at high temperatures and most of them were soluble readily at room temperature in polar solvents.