Synthesis and characterization of polyamides containing heterocyclic thiaxanthone units

Novel polyamides containing heterocyclic thiaxanthone units were prepared by condensing 2,7-dichloroformylthiaxanthone-5,5′-dioxide and 2,8-dichloroformylthiaxanthone-5,5′-dioxide with various aromatic diamines, under low temperature solution polymerization conditions in DMAc. The model diamide, 2,8-ditolylcarbamylthiaxanthone-5,5′-dioxide was synthesised and characterized by spectroscopic methods. The polyamides were prepared in 70–80% yield and had inherent viscosity in the 0.36–0.73 dL/g range. The poyamides have decomposition temperatures in the 425–510°C range in nitrogen. The effect of thiaxanthone rings on polymer backbone on solubility, crystallinity, and thermal stability is also discussed.     

Synthesis and characterization of polyimides containing heterocyclic units

Five new polyimides containing phenoxaphosphine as well as dibenzothiophene, phenoxathiin, and thianthrene units have been synthesized from 10-phenylphenoxaphosphine-2,3,7,8-tetracarboxylic dianhydride-10-oxide and heterocyclic diamines by the cyclopolycondensation method. These polyimides had inherent viscosities in the 0.75–1.10 dL/g range in conc. H₂SO₄ at 30°C. All the polymers were characterized by elemental analysis, density, solubility, crystallinity, IR spectra, and thermal methods.     

Synthesis and photoreactions of polyesters containing triazene and cinnamylidene malonyl units

The synthesis and photoreactions of polyesters containing the photolabile triazene group (Ph NN NR₂) as well as photocrosslinkable units based on substituted cinnamylidene malonyl moieties are reported. The polyesters were obtained by reacting a triazene containing difunctional alcohol with different substituted cinnamylidene malonic acid dichlorides. Irradiation at λ > 395 nm enables selective photocrosslinking of the cinnamylidene malonyl ester units via [2+2]π‐cycloaddition without affecting the triazene units. The photocrosslinking reaction of the triazene containing polyesters as well as triazene‐free reference polyesters were investigated by UV and IR spectroscopy. After selective photocrosslinking the irradiated polymers became insoluble and no longer exhibited a T_g below decomposition temperature. The crosslinked triazene containing polyesters show strong absorption at λ = 308 nm and are therefore interesting candidates for applications using XeCl excimer laser ablation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1903–1910, 2000     

Synthesis of aliphatic polyesters containing tetracyanoquinodimethane units by low-temperature polycondensation reactions

The low-temperature solution polycondensation reaction between 1,4-bis-(2′-hydroxy-ethoxy)benzene and adipyl chloride has been studied in N,N-dimethylacetamide. The effect of temperature, concentration, and reaction time on the percent yield and product viscosity has been determined. Optimum conditions were established for the preparation of high molecular weight products and then applied to the synthesis of novel tetracyanoquinodimethane polyesters. Products were characterized by gel permeation chromatography.     

Synthesis and characterization of new poly(arylene ether)s containing heterocyclic units. II.

A series of new poly(arylene ether)s, containing naphthalene, pyridine, and quinoline units have been prepared by solution condensation polymerization. The synthesis involves nucleophilic displacement of aromatic dihalides with aromatic potassium bisphenates in an anhydrous dipolar aprotic solvent at elevated temperatures. The polymers, having inherent viscosity from 0.24 to 1.32 dL/g, were obtained in quantitative yield, have excellent thermal stability as shown by 10% weight loss temperatures in nitrogen and air (above 450 and 430°C, respectively) and high glass transition temperatures (in the range of 150–220°C). The introduction of quinoline moieties in the polymer backbone positively influences the thermal properties, such as high T_g/T_m ratios. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of polyfluorenes containing bisphenazine units

Novel conjugated copolymers based on 9,9‐dioctylfluorene and bisphenazine (BP) were synthesized by Suzuki polymerization. Energy transfer from the conjugated main chain to the BP moieties was observed. Full energy transfer was achieved when the molar content of the bisphenazine was 20% (20BPPF) in toluene solution. The similar phenomena were observed even for 1% bisphenazine content copolymer (1BPPF) in film. The lowest occupied molecular orbital (LUMO) energy levels (?3.06 eV) of the copolymers were lower than that of the polyfluorene homopolymer (PFO; ?2.65 eV), indicating that the introduction of the BP unit was benefit to electron injection. Single‐layer electroluminescent devices (ITO/PEDOT:PSS/polymer/LiF/Al) were fabricated to investigate their electroluminescence (EL) performances. The maximum brightness and current efficiency of all BPPF copolymers surpassed the PFO homopolymer. The best single‐layer device was based on 5BPPF, with a maximum brightness of 1532 cd/m² and current efficiency of 1.09 cd/A. Much higher efficiency could be achieved for multilayer EL devices of 5BPPF (ITO/PEDOT:PSS/PVK/polymer/TPBI/LiF/Al), which showed a maximum current efficiency of 10.01 cd/A. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1990–1999, 2010     

Synthesis and characterization of new aromatic polyesters containing cardo decahydronaphthalene groups

Three cardo bisphenols containing decahydronaphthalene group viz., 4,4′-(octahydro-2(1H)-naphthylidene)bisphenol, 4,4′-(octahydro-2(1H)-naphthylidene)bis-3-methylphenol and 4,4′-(octahydro-2(1H)-naphthylidene)bis-3,5-dimethylphenol were synthesized starting from commercially available 2-naphthol and were utilized for synthesis of new aromatic polyesters by phase transfer-catalyzed interfacial polycondensation with isophthaloyl chloride, terephthaloyl chloride and a mixture of isophthaloyl chloride and terephthaloyl chloride (50:50 mol %). Inherent viscosities and number average molecular weights (M_n) of polyesters were in the range 0.35-0.84 dL/g and 13,300-48,500 (Gel Permeation Chromatography, polystyrene standard), respectively. Polyesters were readily soluble in organic solvents such as dichloromethane, chloroform, tetrahydrofuran, meta-cresol, pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, and 1-methyl-2-pyrrolidinone at room temperature and could be cast into tough, transparent and flexible films from their chloroform solutions. Wide-angle X-ray diffraction measurements revealed the amorphous nature of polyesters. The glass transition temperature of polyesters was in the range 207-287 °C. The temperature at 10% weight loss (T₁₀), determined from thermogravimetric analysis of polyesters, was in the range 425-460 °C indicating their good thermal stability.     

Thermotropic main chain liquid crystalline polyesters containing ferrocene and phosphate units: synthesis and characterization

A new series of liquid crystalline main chain copolyesters were prepared, having ferrocene in the mesogenic segment and a methyl phosphate group along with a methylene spacer. The even numbered methylene groups were varied from two to ten. Liquid crystalline behaviour was investigated on a hot stage optical polarized microscope. Thermal properties of the polymers were analysed by TGA and DSC, revealing that the polymers yield high char products, probably caused by the formation of phosphorus and iron oxides. The glass transition (T _g) temperatures of the polymers were found to be fairly low, the result of the incorporation of bulky phosphorus and ferrocene moieties in the chain. The phase behaviour was analysed and correlated with the structure of the polymers. The liquid crystalline textures of the polymers became more transparent with increasing spacer length. Energy minimized structures for the polymer repeating units reveal that both the ferrocene and phosphorus moieties produce more molecular entanglement, thus reducing the T _g and T _m of the polymers.     

Thermotropic main chain liquid crystalline polyesters containing ferrocene and phosphate units: synthesis and characterization

A new series of liquid crystalline main chain copolyesters were prepared, having ferrocene in the mesogenic segment and a methyl phosphate group along with a methylene spacer. The even numbered methylene groups were varied from two to ten. Liquid crystalline behaviour was investigated on a hot stage optical polarized microscope. Thermal properties of the polymers were analysed by TGA and DSC, revealing that the polymers yield high char products, probably caused by the formation of phosphorus and iron oxides. The glass transition (T_g) temperatures of the polymers were found to be fairly low, the result of the incorporation of bulky phosphorus and ferrocene moieties in the chain. The phase behaviour was analysed and correlated with the structure of the polymers. The liquid crystalline textures of the polymers became more transparent with increasing spacer length. Energy minimized structures for the polymer repeating units reveal that both the ferrocene and phosphorus moieties produce more molecular entanglement, thus reducing the T_g and T_m of the polymers.     

Synthesis, characterization and degradation of well-defined crosslinkable aliphatic polyesters end-capped by biomesogenic units

Novel biodegradable-cum-crosslinkable polyesters end-capped by biomesogenic units, cinnamic acid (CA) and ferulic acid (FA), were synthesized via chain-growth polycondensation in solid-liquid phase. The chemical structure of synthesized polymers was characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (¹H NMR). The composition of polyesters, which was calculated by ¹H NMR, was in agreement with the feed ratios. The thermal properties and crystallinity of polyesters were measured by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide angle X-ray diffraction (WXRD) and polarizing-light microscopy (PLM). It was found that the polyesters possessed good crystallinity. Furthermore, the obtained polyesters could be crosslinked with methyl methacrylate (MMA), n-butyl acrylate (BA) and styrene (St) under thermal condition. The crosslinked products possessed degradability in phosphate buffer solution at 37 °C, which might be potentially applied as biomaterials.     

Synthesis and characterization of side-chain liquid-crystalline polysiloxanes containing fluorinated units

Several new chiral side-chain LC polysiloxanes (IP–VIIP) bearing fluorinated methyl groups were synthesized with a cholesteric LC monomer and a non-LC monomer containing fluorinated units. The chemical structures and LC properties of the monomers and polymers were characterized by use of various experimental techniques. The effect of copolymer composition on mesomorphic properties of the fluorine-containing polymers was studied as well. The obtained polymers were soluble in many solvents and the specific rotations showed negative values. The temperatures at which 5% weight loss occurred (T _d) were greater than 300 °C for all the polymers and the residue weight on heating to 600 °C increased slightly with increase of the monomer containing fluorinated units in the polymer systems. All the polymers displayed two-phase transitions when they were heated and cooled. The IP, IIP, and IIIP exhibited cholesteric textures when they were heated and cooled, while IVP, VP, VIP, and VIIP showed smectic fan-shaped textures. XRD curves of samples of IVP, VP, VIP, and VIIP displayed sharp and strong peaks at low angle, but no sharp peaks were shown at low angle for the samples IP, IIP, and IIIP.     

Synthesis and characterization of conjugated polymer containing azobenzene and oxadiazole units

A novel conjugated polymer containing azobenzene and oxadiazole units was synthesized through multi-step synthesis.The structures and properties of monomer and polymer were characterized and evaluated with IR,1H NMR,UV,TGA and GPC,respectively.Polymer with long side chain of alkoxy shows good solubility,thermal stability and photoisomerization property.     

Synthesis and characterization of novel low band-gap polymers containing squaraine units

Novel conjugated polymers based on squaric acid having 2,5-Bis[(E)-N-alkylpyrrol-2-ylvinyl]-3-alkylthiophene(PVTVP) unit in the main chain were successfully synthesized in good yields through polycondensation reaction.Their molecular structures were characterized by FT-IR and ~1H NMR.They have good solubility in common organic solvents,good thermal stability by thermal gravimetric analysis and high molecular weights.Their optical properties were investigated by UV-vis absorption spectra in CH_2Cl_2 solution,the results indicated all these compounds showed broad and strong spectral responses from 200nm to 900nm, suggesting their potential for application as organic plastic solar cells.     

Synthesis and properties of polyesters containing naphthalenetetracarboxylic imide

Poly(ethylene naphthalates) containing small contents of N, N'-bis(ω-hydroxypropyl)naphthalene-1, 4, 5, 8-tetracarboxylic imide(HPNTI) unit as the photostabilizing component, which are stable to ultraviolet lights, were synthesized from dimethyl naphthalate, ethylene glycol, and HPNTI. The polyesters obtained were characterized by fluorescence spectroscopy and measurements of molecular weights and thermal properties.     

Synthesis and characterization of new cardo polyesters

New phthalide-containing bisphenols, phenolphthalein-N-(3-methylanilide) (3-PMA), and phenolphthalein-N-(4-methylanilide) (4-PMA), were synthesized from phenolphthalein and m- and p-toluidines. These bisphenols were polycondensed with terephthaloyl chloride (TPC) using an interfacial or solution polymerization technique to yield new polyesters. Copolymers were also obtained by utilizing different molar proportion of phenolphthalein (PPH) and 3-PMA or 4-PMA with TPC. The polymers prepared by solution polymerization were obtained in 93–99% yields and showed reduced viscosities in the range 0.37–0.83 dL/g. They were readily soluble in chlorinated hydrocarbons and aprotic polar solvents. The polyesters showed glass transition temperatures in the range 261–300°C as measured by DSC. Thermogravimetric analysis of the polyesters indicated no weight loss below 408°C under N₂ atmosphere. Structure–property correlations among these cardo polyesters have been discussed. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3227–3234, 1997     

Synthesis and characterization of twin mesogens containing siloxane units as central spacers

A mesogenic ester, 4-hexyloxyphenyl 4-vinyl benzoate was synthesized and studied. The synthesis and characterization of bimesogenic molecules employing this ester with oligosiloxane spacers of different lengths are described. The compounds were characterized by IR ¹H NMR, elemental and thermal analysis, and polarized light microscopy.     

Synthesis and characterization of difunctional blue light-emitting molecules containing hole-transporting triphenylamino units

The synthesis of new difunctional (i.e., light-emitting and hole-transporting) fluorophore molecules, 2,2′-difuryl-4,4′-(N,N,N′,N′-tetraphenyl)diaminobiphenyl and 5,5′-bis(4-N,N′-diphenylaminophenyl)-2,2′-bifuryl, which contain hole-transporting triphenylamino units, are reported. These difunctional molecules emit intense blue photoluminescence and further reveal high HOMO energy values as well as high glass transition temperatures.     

Synthesis and characterization of fluorinated liquid-crystalline elastomers containing chiral liquid-crystalline crosslinking units

Fluorinated chiral liquid-crystalline elastomers (LCEs) were graft copolymerized by a one-step hydrosilylation reaction with polymethylhydrogenosiloxane, a fluorinated LC monomer 4-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoyloxy)phenyl 4-(undec-10-enoyloxy)benzoate (PPUB) and a chiral crosslinking LC monomer (3R,3aR,6S,6aR)-6-(undec-10-enoyloxy)hexahydrofuro[3,2-b]furan-3-yl 4′-(4-(allyloxy)benzoyloxy)biphenyl-4-carboxylate (UHAB). The chemical structure, liquid-crystalline behavior and polarization property were characterized by use of various experimental techniques. The effective crosslink density of the LCEs was characterized by swelling experiments. The thermal analysis results showed that the temperatures at which 5% weight loss occurred were greater than 250 °C for all the LCEs, and the residue weight nearby 600 °C increase with increasing chiral crosslinking components in the polymer systems. All the samples showed chiral smectic C mesophase when they were heated. The glass transition temperature and mesophase-isotropic phase transition temperature of fluorinated elastomers increased slightly with increase of chiral crosslinking mesogens in the polymer systems, but the enthalpy changes of mesophase-isotropic phase transition decreased slightly. In XRD curves, all the samples exhibited strong sharp reflections at small angles suggesting smectic layered packing arrangement. These fluorinated chiral LCEs showed 0.1–0.2 μC/cm² of spontaneous polarization with increasing chiral crosslinking component.