High-temperature Polycondensation Research Articles

Nowe aromatyczne poliamidoimidy - synteza oraz wlasciwosci termiczne i fotoluminescencyjne

New aromatic polyamideimides (PAI) were synthesized by high temperature polycondensation from diamidedianhydrides (formerly prepared by us) and diamines: 1,5-diaminonaphthalene, 4,4'-(hexafluoro-isopropylidene)-dianiline or 2,6-diamineanthraquinone. Chemical structures of PAI obtained (Fig. 1) were confirmed by FTIR (Fig. 2) and NMR (Fig. 3) methods and by elemental analysis. Polyamideimides studied showed high thermal stability both in nitrogen or air atmosphere as well as high glass transition temperature in the range 220-265 °C (Table 1). An evaluation of optical and photoluminescent properties of PAI in NMP solutions (Fig. 4 and 5) showed that they emit the light of wavelength in the range 405-572 nm, dependently on the structure.

Fluorene‐rich high performance polyesters: Synthesis and characterization of 9,9‐fluorenylidene and 2,7‐fluorenylene‐based polyesters with excellent optical property

AbstractPolyesters PEs containing high content of fluorene units in their backbones were synthesized from 9,9‐diarene‐substituted fluorene diols (1) and fluorene‐based diacid chlorides (2) by high temperature polycondensation at 185 °C in diphenyl ether. The molecular weights of the polyesters PE1‐PE5 were in a range of Mw 25,000–165,000. The polyesters displayed their high thermostability: the glass transition temperatures (Tg) by differential scanning calorimetry analysis ranged from 109 to 217 °C, while the 10% weight loss temperatures (Td10) measured by thermogravimetric analysis were over 400 °C in nitrogen and 395 °C in air. The polyesters had good solubility in most common organic solvents such as chloroform and toluene and gave tough, transparent and flexible cast films. The transmittance of the films was over 80% in the wavelength range from 450 to 700 nm in any PEs. The PEs exhibited high refractive index values around 1.65, while they had very low degree of birefringence. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2549–2556, 2008

Novel polyfluorinated polyimides derived from α,α-bis(4-amino-3,5-difluorophenyl)phenylmethane and aromatic dianhydrides: Synthesis and characterization

A novel aromatic diamine containing bulky lateral phenyl unit and fluorine groups ortho-substituted to the amino groups in the structure, α,α-bis(4-amino-3,5-difluorophenyl)phenylmethane (4FMA) was synthesized and characterized. 4FMA was polymerized with four aromatic dianhydrides to afford a series of polyimides (PIs) via a one-step high-temperature polycondensation procedure. All the PIs were amorphous and showed good solubility not only in polar aprotic solvents, but in many common solvents, such as cyclopentanone and tetrahydrofuran. The soluble polymers formed flexible, tough and transparent films. The films had a tensile strength, elongation at break, and tensile modulus in the ranges 85–107MPa, 4–7%, 1.7–2.8GPa, respectively. The polyimides also exhibited high-Tg (292–338°C), good thermal stability, good dielectric strength, low dielectric constants, and low water uptakes due to the introduction of the polyfluorinated substituents in the polymer backbone. As expected, the PI films showed good transparency in the UV–Vis light region with cutoff wavelength as low as 318nm and transmittance higher than 60% at 450nm. PI-4 derived from 4FMA and fluorinated dianhydride 6FDA exhibited low light-absorption in the near-infrared region, especially at the optocommunication wavelength of 1310nm and 1550nm. The remarkable combined properties indicate their potential applications in microelectronic and optoelectronic fabrications.

Synthesis and Characterization of Organosoluble Polysiloxaneimides Derived from Siloxane-containing Aliphatic Dianhydride and Various Aromatic Diamines

A new siloxane-containing monomer, 5,51- exo-(1,1,3,3,5,5-hexamethyl-trisiloxane -1,5-diyl) bisbicyclo[2,2,1]heptene-2,3- endo-dicarboxylic anhydride (3) was synthesized by the hydrosilylation reaction of 1,1,3,3,5,5-hexamethyl-trisiloxane (1) and cis-5-norbornene- endo-2,3-dicarboxylic anhydride (2). A series of organosoluble polysiloxaneimides (PI 5a-e) was prepared from the dianhydride 3 and several aromatic diamines 4 by a one-step high-temperature polycondensation method and the structures were characterized by IR and NMR. The effects of the main chain siloxane groups on the properties of PIs were evaluated by solubility, thermal stability and dielectric properties in addition to optical and water adsorption. The PIs were readily soluble in polar aprotic solvents such as NMP, DMAc and CHCl 3 at room temperature, except PI 5a, which was only soluble in polar amide type solvents at elevated temperature. PIs 5a-e had glass transition temperatures between 138 and 251°C in N2 and the 5% weight loss temperature ranged from 460 to 470°C under air. The PIs could be cast into flexible and tough films from DMAc solution. The films had tensile strengths of 44—52 MPa, tensile moduli of 0.56—0.68 GPa and elongations at break from 5.8—7.9%. The PI films exhibited good optical UV-vis transparency with wavelength cutoff of 269—289 nm and transmittances over 90% at 400 nm, and dielectric constants of about 2.76—2.65 with low water adsorption (0.3—0.4%).

Gas transport properties of high free volume polyarylates based on isophthalic/terephthalic acid chloride mixtures

This paper reports the synthesis and the gas transport properties measured for polyarylates obtained by high temperature polycondensation of tetramethyl (TMBPA), hexafluoro (HFBPA) and tetramethyl hexafluoro (TMHFBPA) bisphenol A with a mixture of isophthalic (I) and terephthalic (T) acid chlorides (50 mol% initial I/T ratio). The polymers show high glass transition temperature (above 180 °C), good solubility in chlorinated solvents as well as excellent thermal stability (decomposition temperatures above 420 °C). The membranes produced from these I/T polyarylates are transparent and flexible films, and in addition, they have a gas permeability and selectivity balance of properties that falls on, for O 2/N 2, and close to, for CO 2/CH 4, the experimental “upper bound” limit pointed out by Robeson. The polyarylate membranes based on TMHFBPA I/T lead to the very attractive permeability coefficients of 182, 55, and 16 Barrers for the gases He, CO 2 and O 2 with the corresponding still attractive ideal selectivity factors of 106, 32 and 5.7 for the pair of gases He/CH 4, CO 2/CH 4 and O 2/N 2. The results reported in this paper are interpreted in terms of the fractional free volume and the most probable inter-segmental distance measured from density determinations and X-rays diffraction patterns.

Synthesis and photophysical properties of polyphenylquinoxalines with thiophene and dibenzothiophene units in the backbone

New bis(α-diketones) containing thiophene and dibenzothiophene groups were synthesized. Via the reaction of these monomers with aromatic tetramines under high-temperature polycondensation conditions, a series of new polyphenylquinoxalines combining high thermal and mechanical characteristics with solubility in organic solvents were prepared. Polyphenylquinoxalines exhibit intense fluorescence in solution and in thin films with maxima in the region of 432–522 and 450–530 nm in the case of thiophene-containing and dibenzothiophene derivatives, respectively.

Synthesis of polyoxyethylene block copolymers and their aggregation in water

The possibility of thermal degradation of polyoxyethylene in the course of high-temperature polycondensation was examined. Conditions were suggested for the low-temperature synthesis of ABA block copolymers whose molecules contain a polyoxyethylene central block and p-aromatic ester terminal blocks. The aggregation of the block copolymers in water was studied by dynamic light scattering and electron microscopy.

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.

The potential of cycloaddition reactions in the synthesis of dendritic polymers

Cycloaddition (CA) reactions have attracted recently strong interest not only for the preparation of linear polymers but also for the synthesis and modification of dendritic architectures. This review focuses mainly on the potential of various cycloaddition reactions in the field of dendrimers and especially hyperbranched polymers. The [4 + 2] Diels–Alder cycloaddition, [2 + 2 + 2] CA as well as 1,3-dipolar CA reactions including “click chemistry” will be addressed, and advantages of these reactions will be highlighted. High selectivity, thus high tolerance towards additional functionalities, high yields and often moderate to mild reaction conditions distinguish CA reactions from the often applied classical high-temperature polycondensation type reactions used mainly to synthesize hyperbranched polymers. Thus, besides the high potential in the synthesis and modification of perfectly branched dendrimers, cycloaddition reactions proved also very suited to prepare new types of hyperbranched structures.

Synthesis and Characterization of Linear Homopolyesters Containing s-Triazine Rings

Eight homopolyesters were synthesized by high temperature polycondensation of 2-(N-1-naphthylamine)-4,6-bis (naphthoxy-2-carbonyl chloride)-s-triazine [NANCCT]with each of the eight diols: Bisphenol-A(BPA), bisphenol-C(BPC), phenolphthalein(ph), resorcinol(R), hydroquinone(Hq), catechol(C), 1,5-dihydroxy naphthalene (1, 5-DHN), and ethylene glycol (EG). All the polyesters were characterized by solubility, density, viscosity measurements, IR spectra, NMR spectroscopy, and thermogravimetric analysis.

Synthesis and Properties of Novel Polycyanurates Derived from 2-(N-piperidino)-4,6-bis (naphthoxy-2-carbonyl chloride)-s-triazine

Various polyamides containing s-triazine rings in the main chain were synthesized by high temperature polycondensation of 2-(N-piperidino)-4,6-bis(naphthoxy-2-carbonyl chloride)-s-triazine [PNCCT] 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 viscosity measurements, IR spectra, NMR spectra, and thermogravimetric analysis.

Comparison of one-step and two-step methods of polyimidization and substitution effect in the synthesis of new poly(ester-imide)s with bulky pendent group

New naphthalene-ring containing ester diamines, as new monomers for the preparation of polyimides were synthesized via two successive reactions. Nucleophilic reaction of 3,5-dinitrobenzoylchloride with 1-naphthol and 2-naphthol in the presence of sodium hydroxide led to the preparation of 1- and 2-(3,5-dinitrobenzoyloxy)naphthalene, respectively. Next step was reduction of them by hydrazine hydrate/Pd–C to produce 1- and 2-(3,5-diaminobenzoyloxy)naphthalene. All the prepared compounds were characterized by common spectroscopic methods. These ester containing aromatic diamines with pendent naphthalene group were used to prepare soluble polyimide copolymers via two different methods: catalyzed one-step high-temperature polycondensation in m-cresol, and two-step polycondensation in NMP and subsequent chemical dehydration. The obtained poly(ester-imide)s were characterized and their properties were studied. One-step and two-step methods for the preparation of five-membered ring polyimides were compared. Polymers prepared through one-step method showed higher yield and inherent viscosities and therefore better physical properties.

The synthesis, characterization, and crystal structures of poly(2,6‐naphthalenebenzobisoxazole) and poly(1,5‐naphthalenebenzobisoxazole)

AbstractThe rigid‐rod polymers, poly(2,6‐naphthalenebenzobisoxazole) (Naph‐2,6‐PBO) and poly(1,5‐naphthalenebenzobisoxazole) (Naph‐1,5‐PBO) were synthesized by high temperature polycondensation of isomeric naphthalene dicarboxylic acids with 4,6‐diaminoresorcinol dihydrochloride in polyphosphoric acid. Expectedly, these polymers were found to have high thermal as well as thermooxidative stabilities, similar to what has been reported for other polymers of this class. The chain conformations of Naph‐2,6‐PBO and Naph‐1,5‐PBO were trans and the crystal structures of Naph‐2,6‐PBO and Naph‐1,5‐PBO had the three‐dimensional order, although the axial disorder existed for both Naph‐2,6‐PBO and Naph‐1,5‐PBO. Naph‐2,6‐PBO exhibited a more pronounced axial disorder than Naph‐1,5‐PBO because of its more linear shape. The repeat unit distance for Naph‐2,6‐PBO (14.15 Å) was found to be larger compared with that of Naph‐1,5‐PBO (12.45 Å) because of the more kinked structure of the latter. The extents of staggering between the adjacent chains in the ac projection of the crystal structure were 0.25c and 0.23c for Naph‐2,6‐PBO and Naph‐1,5‐PBO, respectively. Naph‐1,5‐PBO has a more kinked and twisted chain structure relative to Naph‐2,6‐PBO. The kinked and twisted chain structure of Naph‐1,5‐PBO in the crystal seems to prevent slippage between adjacent chains in the crystal structure. The more perfect crystal structure of Naph‐1,5‐PBO may be due to this difficulty in the occurrence of the slippage. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1948–1957, 2006

Influence of the structure of new poly(amide-imide)s on their optical properties

Abstract Two classes of poly(amide-imide)s with mono- and bisazoaromatic chromophores in the side chain have been synthesized using one-step hightemperature polycondensation. The influence of the structures of the macromolecules on their properties was investigated. Preliminary results of the kinetics of holographic grating recording using 514.5 nm Ar+ laser light for chosen poly(amideimide) films are presented. The gratings were recorded using two linearly polarized beams with s-s or s-p configurations. For comparative purposes all experimental conditions (light intensity, two-beams intersection angle) were kept unchanged. It was found that time constants of grating build-up were significantly larger for polymers containing a chromophore with two azo groups when compared with the same polymers having a single azo group. On the other hand diffraction efficiencies were lower for polymers containing a chromophore with two azo groups than with a single azo group.

Photoinduced optical anisotropy in new poly(amide imide)s with azobenzene units

Two series of new photosensitive poly(amide imide)s (PAIs) containing photochromic azobenzene moieties as side groups have been synthesized. For this purpose the following diamines with azobenzene groups have been prepared: 2,4-diamino-4′-fluoroazobenzene, 2,4-diamino-4′-methylazobenzene, 2,4-diamino-4′-trifluoromethoxy-azobenzene and 2,4-diamino-4′-nitroazobenzene. The poly(amide imide)s have been obtained from diamidedianhydrides and diamino-chromophores using high-temperature polycondensation. The resulting polyimides are characterized by good solubility in some solvents, high glass transition temperatures (257–280 °C), high thermal decomposition temperatures and good film forming properties. The irradiation with linearly polarized light (488 nm, 100 mW/cm 2), causes a reorientation of the azobenzene groups by angular-selective EZ photoisomerization. In this way optical anisotropy is induced in the initially isotropic films casting from the amorphous polymers. The photoinduced dichroism in the films has been measured, and the results are discussed in relation to the structure of these polymers, whereas the substitution of the azobenzene moiety and the structure of the backbone are varied.

Studies on second harmonic generation efficiency by a series of chiral polyesters

A series of optically active main-chain polyesters were synthesized by high-temperature polycondensation from biphenolic azo chromophores, (2R,3R)-(+)-diethyl tartrate and terephthaloyl chloride. The polyesters showed glass transition temperatures in the range of 100–135°C and were thermally stable to 350°C. The second harmonic generation efficiency of the polyesters was studied by the powder method and as thin films with 2-methyl-4-nitroaniline as a reference. The SHG efficiency of the polymers was compared with that of low molecular weight chromophores. The polymers with chiral units showed good second harmonic generation efficiency. The SH signal also showed good temporal stability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 11: 2468–2473, 2003

Second harmonic generation and polar order in thin films of polyesters

A series of optically active main chain polyesters were synthesized by high temperature polycondensation from biphenolic azo chromophores with azobenzene-4,4′-dicarbonylchloride and 1,4:3,6-dianhydro-D-sorbitol ([α]D25=+42.5°). The second harmonic generation of the polyesters is studied in thin films. The polar order in films is determined from the UV-visible absorption spectra. The variation in SHG intensity with chiral monomer concentration is explained as a function of polar order. The polymers with chiral units showed good second harmonic efficiency. The intensity of second harmonic light (532 nm) increased with angle of incidence and indicated the polar order in the plane of the film. The SH signal also showed good temporal stability.

Synthesis and Characterization of Aromatic Polyamides Obtained from 4-4'-(9-Fluorenylidene)Diamine, 4-4'-(Hexafluoro-Isopropylidene)Dianiline and 4-4'-Diamine-Benzophenone

Nine aromatic polyamides were synthesized from three different diamines by high-temperature polycondensation using three different aromatic diacid chlorides. A comparison of the effect that structural modifications afforded by the substitutions at the diacid chloride phenyl position and the introduction of bulky side groups in the diamine contribution were evaluated. Polyamide properties were characterized by DSC, TGA, wide angle x-ray scattering, density, light scattering and solubility. Differential scanning calorimetry measurements indicated that all polymers have high glass transition temperatures ranging from 236 to 319 'C, while thermogravimetrical measurements show that the onset of decomposition of these polymers is above 460 'C and that they are thermally stable. It was also found that almost all polymers were soluble in polar aprotic solvents. The results indicate that introduction of bulky side groups in the structure of the aromatic polyamides increases the Tg, while packing efficiency is lowered by these aromatic groups. Furthermore, the hexafluoro substitution in the polyamides raises their thermal stability, which may be attributed to the strong C-F bond. A relationship between Tg and the conformational entropy determined by structure was found, indicating that the higher the rigidity of the polyamide the higher the Tg. Moreover, the incorporation of bulky side groups on the structure increases the Tg more than an increase on rigidity, which indicates that the effect of intermolecular interactions is more important for an increase in Tg than the effect of chain stiffniess.

Synthesis and characterization of (2R, 3R)-(+)-diethyl tartrate-based chiral polyesters designed for second harmonic generation

A novel synthetic approach has been devoleped to incorporate donor-acceptor substituted π-conjugated segments and chiral centres in main-chain polymeric systems. A series of optically active main-chain polyesters were synthesized by high-temperature polycondensation from biphenolic azo chromophores, (2R,3R)-(+)-diethyl tartrate, and terephthaloyl chloride. The biphenolic chromophores were bis(4-hydroxyphenylazo)-2,2′-dinitrodiphenylmethane and bis(4-hydroxyphenylazo)-2,2′-dinitrodiphenylsulfone. The effects of solvent, reaction time, and temperature on the polymerization were investigated. The optical activity of the polymers showed that the introduction of a substantial amount of chiral groups in the polymer chain leads to the formation of non-centric configurations. The chiral order was found to be thermally stable. The polyesters showed glass transition temperatures in the range 100–190°C and were thermally stable up to 350°C. All polyesters showed positive solvatochromism in UV–visible absorption spectra.

Synthesis and characterization of organosoluble aliphatic–aromatic copolyimides based on cycloaliphatic dianhydride

A series of aliphatic–aromatic polyimides have been synthesized. These polyimides were prepared by high-temperature polycondensation of the aliphatic diamines: 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane and 4,4 ′-methylenebis(2,6-dimethylaniline) with 1,2,3,4-cyclopentanetetracarboxylic dianhydride. Various ratios of diamines (aromatic:aliphatic) have been applied for preparation of copolyimides. Polycondensation proceeded at 190 °C and produced copolyimides with reduced viscosities up to 0.92 dl/g. The polyimides were soluble in a wide range of organic, common solvents and showed high-thermal stability. In most cases these polymers formed flexible films which presented excellent transparency.