Syntheses and properties of aromatic polyamides derived from 4,4′-oxydibenzoic acid and aromatic diamines

A series of aromatic polyamides were synthesized by direct polycondensation of 4,4-oxydibenzoic acid with various aromatic diamines inN-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride, using triphenyl phosphite and pyridine as condensing agents. The resultant polyamides had inherent viscosities of 0.21-1.48 dL/g. Most of the polymers were organo-soluble and could be solution-cast into flexible and strong films. The glass transition temperatures (T_gs) of most polyamides could be determined with the help of differential scanning calorimetry (DSC) traces, which were recorded in the range of 170–275 °C. Thermogravi metric data of these polymers indicated that most of the polyamides showed no significant weight loss before 450 °C in either air or nitrogen atmospheres.     

Highly soluble phenylethynyl terminated oligoimides derived from 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane, 4,4′-oxydianiline and mixed thioetherdiphthalic anhydride isomers

Novel highly soluble phenylethynyl-endcapped oligoimides derived from mixed thioetherdiphthalic anhydride isomers (m-TDPA) and 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindane (DAPI), 4,4′-oxydianiline (4,4’-ODA) with 4-phenylethynylphthalic anhydride (PEPA) as a reactive endcapping agent were synthesized. The calculated molecular weights of all the oligoimides were 2500 g·mol^?1.The effect of the mole ratio of DAPI/4,4’-ODA on solubility and melt viscosity of oligoimides as well as the thermal and mechanical properties of cured polyimide films was investigated. Experimental results indicated that DAPI greatly improved the solubility (>30 wt.%) of the oligoimides in low boiling points solvents when the content of DAPI was more than 10 mol% per total diamine. All the oligoimides exhibited very good processability with minimum melt viscosity lower than 60 Pa·s at about 330 °C. Tough and brown films were obtained after thermally cured at 370 °C for 1 h and dynamic mechanical analysis (DMA) showed that glass transition temperatures of the cured films increased up to 340 °C with the increasing content of DAPI. However, the thermal stability and mechanical properties decreased with the increase of DAPI content. The temperature of 5% weight loss was higher than 470 °C in both air and N₂ atmosphere obtained by thermogravimetric analysis (TGA). And the tensile strengths of the cured films were about 60 MPa.     

Synthesis and properties of polyimides based on isomeric (4, 4′-methylenediphenoxyl) bis (phthalic anhydride)s (BPFDAs)

Isomeric (4, 4′-methylenediphenoxyl) bis (phthalic anhydride)s (BPFDAs)were synthesized and their structures were determined via IR spectra and ¹H NMR. Polyimides were then prepared from isomeric BPFDAs and aromatic diamines in N, N-Dimethylacetamide (DMAc) via the conventional two-step method. Polyimides based on 3, 3′-BPFDA are soluble in common organic solvents at room temperature, while polyimides based on 4, 4′-BPFDA were only partially soluble in high-boiling-point solvent even upon heating. The 5% weight-loss temperatures (T _5% ) of these polyimides were in the range of 430–500 °C in air. Dynamic mechanical thermal analysis (DMTA) indicated that the glass-transition temperatures of polyimides from 3, 3′-BPFDA are around 10–20 °C higher than those of polyimides from 4, 4′-BPFDA. The wide-angle X-ray diffraction showed that all polyimides are amorphous.     

Synthesis of soluble polyarylenes containing alternating 4,4′-(1,1′-binaphthyl) and 4,4′-(3,3′-diphenyl)biphenyl structural units

Summary The synthesis and Ni(0) catalyzed homocoupling polymerization of 4,4-bis[5-(trifluoromethanesulfonyloxy)-2-biphenylyl]-1, 1-binaphthyl (9) are described. This polymerization reaction produces a soluble polyarylene containing alternating 4,4-(1,1-binaphthyl) and 4,4-(3,3-diphenyl)biphenyl structural units.     

Polyamide derived from 4,4′-thiobis(methylene)dibenzoyl chloride and aliphatic diamine: interfacial synthesis and characterization

A series of processable semi-aromatic polyamides containing thioether and methylene units were synthesized through the reaction of 4,4′-thiobis(methylene)dibenzoyl chloride and aliphatic diamine by the method of interfacial polycondensation. These polyamides had excellent thermal properties with glass transition temperatures (T _g) of 104.3–130.6 °C, melting temperatures (T _m) of 300.3–303.8 °C, and initial degradation temperatures (T _d) of 405.2–410.3 °C. They had wider processing windows than traditional semi-aromatic polyamides (such as PA6T can not be processed by melting) and can be processed by melting method. They had better tensile strengths of 57.6–64.1 MPa, low-temperature mechanical properties, low water absorption of 0.19–0.27 %, low dielectric constants of 3.11–3.95 at 100 kHz, and better melt flowability properties of 232–60.7, 301.9–78.8, and 423.1–83.6 Pa s under a shear rate ranging from 20 to 1,170 s^?1, respectively. In addition, these polyamides showed good corrosion resistance, they did not dissolve in solvents such as NMP, DMSO, hydrochloric acid (6 mol/l), and solution of NaOH (1 mol/l) and so on.     

Synthesis and characterization of novel polyimides derived from 4,4’-bis(5-amino-2-pyridinoxy)benzophenone: effect of pyridine and ketone units in the main

A diamine monomer, 4,4’-bis(5-amino-2-pyridinoxy)benzophenone, was designed and synthesized, and used to react with commercially different kinds of aromatic dianhydrides to prepare a series of polyimides containing pyridine and ketone units via the classical two-step procedure. Glass transition temperatures (T_g) of the resultant polyimides PI-(1–5) derived from 4,4’-bis(5-amino-2-pyridinoxy) benzophenone with various dianhydrides ranged from 201 to 310 °C measured by differential scanning calorimetry. The temperatures for 5%wt loss of the resultant polyimides in nitrogen atmosphere obtained from the thermogravimetric analysis curves fell in the range of 472–501 °C. The temperatures for 10%wt loss of the resultant polyimides in nitrogen atmosphere fell in the range of 491–537 °C. Meanwhile, the char yields at 800 °C were in the range of 55.3–60.8%. Moreover, the moisture absorption of polyimide films was measured in the range of 0.37–2.09%. The thin films showed outstanding mechanical properties with tensile strengths of 103–145 MPa, an elongation at break of 12.9–15.2%, and a tensile modulus of 1.20–1.88 Gpa, respectively. The coefficients of thermal expansion of the resultant polyimides were obtained among 26–62 ppm °C^?1. To sum up, this series of polyimides had a good combination of properties applied for high-performance materials and showed promising potential applications in the fields of optoelectronic devices.     

Synthesis,characterization and properties of polyimides from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and imidazole-blocked 2,5-bis[(n-alkyloxy)methyl]-1,4-benzenediisocyanates

Summary By the solution condensation of 3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA) with imidazole-blocked 2,5-bis[(n-alkyloxy)methyl]-1,4-benzenediisocyanates (C_m-BDIs) a series of aromatic polyimides (C_m-BP-PIs) having flexible (n-alkyoxy)methyl (-CH₂O-n-C_mH_2m+1, m=4, 6, 8) side chains were prepared and characterized by IR- and ¹H-NMR spectroscopy and their properties were measured and discussed in respect to the effects of side chains. Inherent viscosities of the polymers were in the 0.23–0.34 dL/g range. All the polymers were highly soluble in N,N-dimethylpropyleneura(DMPU) and C₆- and C₈-BP-PIs even in CHCl₃ at room temperature. UV-VIS spectra showed that the -electrons are delocalized along the main chain. TGA studies showed a two-step pyrolysis behavior and in DSC Tg's of C₄-, C₆- and C₈-BP-PIs were determined to be 184, 135 and 127 °C, respectively. Wide-angle X-ray diffractometry for as-polymerized samples revealed a quite low crystallinity with only loosely developed layered structure.     

One mononuclear single-molecule magnet derived from Dy(III) and dmbpy (dmbpy = 4,4′-dimethyl-2,2′-dipyridyl)

Three β–diketonate mononuclear Ln-based compounds, formulated as [Tb^III(hfac)₃(dmbpy)](1), [Dy^III(hfac)₃(dmbpy)](2) and [Er^III(hfac)₃(dmbpy)](3) (hfac = hexafluoroacetylacetone, dmbpy = 4,4′-dimethyl-2,2′-dipyridyl) have been synthesized and structurally characterized by single crystal X-ray diffraction. Structure characterization reveals that complexes 1, 2 and 3 are isomorphous. Shape measurement shows the coordination geometry of complex 2 is trigonal dodecahedron (D_2d). Magnetic property study indicates complex 2 shows SIM behavior with observed frequency-dependent signals at low temperature.     

Synthesis and characterization of polyimides from 4,4′-(3-(<Emphasis Type="Italic">tert</Emphasis>-butyl)-4-aminophenoxy)diphenyl ether

A novel diamine 4,4′-(3-(tert-butyl)-4-aminophenoxy)diphenyl ether (4) was synthesized from 2-tert-butylaniline and 4,4′-oxydiphenol through iodination, acetyl protection, coupling reaction and deacetylation protection. Then some polyimides (PIs) were obtained by one-pot polycondensation of diamne 4 with several commercial aromatic dianhydrides respectively. They all exhibit enhanced solubility in organic solvents (such as NMP, DMF, THF and CHCl₃ etc.) at room temperature. Their number-average molecular weights are in the range of (2.1–3.7)?×?10⁴ g/mol with PDI from 2.25 to 2.74 by GPC. They can form transparent, tough and flexible films by solution-casting. The light transparency of them is higher than 90% in the visible light range from 400 nm to 760 nm and the cut-off wavelengths of UV–vis absorption are below 370 nm. They also display the outstanding thermal stability with the 5% weight loss temperature from 525 °C to 529 °C in nitrogen atmosphere. The glass transition temperatures (T _g s) are higher than 264 °C by DSC. XRD results demonstrate that these PIs are amorphous polymers with the lower water absorption (<0.66%). In summary, the incorporation of tert-butyl groups and multiple phenoxy units into the rigid PI backbones can endow them excellent solubility and transparency with relatively high T _g s.     

Synthesis,characterization, optical and electrical properties of thermally stable polyazomethines derived from 4,4′-oxydianiline

Three soluble, thermally stable azomethine polymers were synthesized by the oxidative polycondensation of azomethine bisphenols using NaOCl as an oxidant in aqueous alkaline medium. The azomethine bisphenol monomers, 4,4′-oxybis[N-(2-hydroxy-3-methoxybenzilidine)aniline], 4,4′-oxybis[N-(2-hydroxy-5-bromobenzilidine)aniline] and 4,4′-oxybis[N-(2-hydroxynaphthalidine) aniline] were synthesized by the condensation of 4,4′-oxydianiline with three aromatic aldehydes. The structures of the monomers and polymers were confirmed by Fourier Transform infrared spectroscopy, UV–visible, ¹H-NMR and ¹³C-NMR spectroscopic techniques. Morphology of the synthesized polymers was characterized using scanning electron microscope. The thermal stability of the polymers is evidenced by high carbines residue obtained in TGA. Fluorescence spectra showed that the emission maxima centred in the region 420–460 nm for all the compounds with large stokes shift values (?λ_ST). Electrical conductivity of iodine-doped polymers was measured by four-point probe technique. The synthesized polymers have shown good electrical conductivity on iodine doping, and it increases with the increase in iodine vapour contact time. The self-extinguishing property of the synthesized polymers was studied by the calculation of the limiting oxygen index values with van Krevelen’s equation.     

Two d10 coordination polymers based on 4,4′-(hexafluoroisopropylidene)diphthalic acid: Syntheses,structures and physical properties

Two novel coordination polymers, [Zn₂(FA)(4,4′-bipy)₂]·2H₂O (1) and Cd₂(FA)(2,2′-bipy) (2), (H₄FA = 4,4′-(hexafluoroisopropylidene)diphthalic acid, 4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine), have been synthesized under hydrothermal conditions, and their structures were determined by single-crystal X-ray diffraction. Polymer 1 features an unusual three-dimensional (3D) network with (4 · 6² · 8³)(4² · 6² · 8²) topology. Polymer 2 has a complicated 3D framework and crystallizes in non-centrosymmetric space group (Fdd2) belonging to polar point group (C_2v), which displays a strong SHG response and ferroelectric properties. Moreover, the luminescent properties of 1 and 2 have also been investigated.     

Synthesis and characterization of aromatic polyamides derived from various derivatives of 4,4’-oxydianiline

Three aromatic diamines, 2,2′-diiodo-4,4′-oxydianiline (DI-ODA 2), 2,2′-bis[p-(trifluoromethyl)phenyl]-4,4′-oxydianiline (BTFP-ODA 3) and 2,8-diaminodibenzofuran (DADBF 5) were synthesized by using 4,4-oxydianiline (4,4′-ODA) as the starting material. New aromatic polyamides 6, 7 and 8 were prepared from these three diamines and six commercially available aromatic diacids by direct polycondensation, respectively. Polyamides 6 and 7 contained bulky iodide and p-trifluoromethylphenyl substitutents that would hinder the chain packing and increase the free volume. They exhibited good optical transparency in visible light region and showed excellent solubility in organic solvents such as DMSO, DMAc, DMF and NMP. Polyamides 8 containing planar dibenzofuran moieties had the highest glass transition temperatures and decomposition temperatures among these polyamides. Polyamides 6 had the lowest decomposition temperatures due to the presence of weak carbon–iodine bond. All of these polyamides showed amorphous nature evidenced by wide angle X-ray diffraction. No endothermic peaks were observed from DSC thermograms up to their decomposition temperatures. High optical transparency and excellent solubility combined with good thermal stability make these polyamides attractive for potential soft electronics applications.     

The electrochemical properties of polyaniline derivatives: poly(4,4′-diphenylamine methylenes) and poly(4,4′-diphenylimine methines)

Summary The electrochemical properties of poly(4,4-diphenylamine methylenes) and poly(4,4-diphenylimine methines) were investigated by cyclic voltammetry. A dehydrogenation reaction occured when poly(4,4-diphenylamine methylenes) underwent a electrochemical reaction and transformed to poly(4,4-diphenylimine methines). The fully oxidized poly(4,4-diphenylimine methines) had the electrochemical band gaps of 1.60–1.72 eV, which were found to significantly smaller than those of the fully reduced poly(4,4-diphenylamine methylenes).     

4,4′-(4,4′-砜基二苯氧基)二苯甲酰氯(SODBC)的合成

以对甲基苯酚、4,4′-二氯二苯砜为原料,通过亲核取代反应合成了4,4′-二(4-甲基苯氧基)二苯砜,用高锰酸钾将甲基氧化得到4,4′-(4,4′-砜基二苯氧基)二苯甲酸(SODBA),后者在二氯亚砜和路易斯碱的催化下合成了4,4′-(4,4′-砜基二苯氧基)二苯甲酰氯(SODBC)白色固体.用FT-IR、1H-NMR、13C-NMR、DSC等对其进行了表征,实验证明该化合物具有预期的结构和较高的纯度.     

Fabrication and in vitro degradation study of novel optically active polymers derived from amino acid containing diacids and 4,4′-thiobis(2-tert-butyl-5-methylphenol)

Chiral bioactive poly(ester-imide)s (PEI)s were synthesized from N,N′-(pyromellitoyl)-bis-(L-phenylalanine) and N,N′-(pyromellitoyl)-bis-(L-leucine) diacids derived from amino acids with 4,4′-thiobis(2-tert-butyl-5-methylphenol) via direct polycondensation reaction in a system of tosyl chloride, pyridine and N,N-dimethylformamide as a condensing agent. The structures of these polymers were confirmed by FT-IR, ¹H-NMR, specific rotation, elemental and thermogravimetric analysis (TGA) techniques. TGA showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 390 °C, which indicates that the resulting PEIs have a good thermal stability. The biodegradability of the monomers and prepared polymers was investigated in culture media and soil burial test for assessing the susceptibility of these compounds to microbial degradation. The results showed that the synthesized monomers and theirs derived polymers are biologically active and they are nontoxic to microbial growth.     

4,4′-二苯基甲烷二异氰酸酯(MDI)

生产现状:MDI是聚氨酯的主要原料之一,由于受世界性建筑优势的推动和纯MDI基料新用途的出现,MDI牛产获得了迅速发展。1987年世界生产能力为103.4万吨,其中北美40.5万吨、欧洲45.8万吨、亚洲10.9万吨、南美和东欧6.2万吨。1980年世界MDI产量为56.5万吨,1985年达86.6万吨,1980～1985     

Synthesis,characterization and crystal structure of one Mn(II) complex with 4,4′-bisimidazolylbiphenyl and 4,4′-sulfonyldibenzoic acid

One new title compound [Mn₃(BIBP)(sdb)(NO₂⁻)₂(H₂O)₂]_n·2DMF (1) (BIBP = 4,4′-bisimidazolylbiphenyl, sdb = 4,4′-sulfonyldibenzoic acid) has been synthesized under hydrothermal condition. The title compound was characterized by IR spectra, thermal analysis, single crystal and powder X-ray diffraction. Magnetic susceptibility measurements indicate that compound 1 exhibits antiferromagnetic coupling interaction.     

Synthesis and properties of aromatic polyesters and brominated polyesters derived from α,α′-bis(4-hydroxyphenyl)-1,4(or 1,3)-diisopropylbenzene

The interfacial polycondensation technique was used for the preparation of polyarylates and brominated polyarylates. Polyarylates and brominated polyarylates were prepared by mixing a solution of diacid chloride such as terephthaloyl chloride, isophthaloyl chloride, or their mixture in dichloromethane with an aqueous alkaline solution of ,-bis(4-hydroxyphenyl)-1,4(or 1,3)-diisopropylbenzene or ,-bis(4-hydroxy-3,5-dibromophenyl)-1,4(or 1,3)-diisopropylbenzene using triethylbenzylammonium chloride as the phase transfer agent. Moderate to high molecular weight polyarylates with _inh up to 1.27 dL/g were obtained, and most of them could be cast into tough and flexible films depending on the polymer composition. In general, polymers containing more 1,3-isomer or isophthaloyl chloride moieties gave transparent and flexible films and had lower glass transition temperatures and higher solubility. Although these polymers have two isopropylidene linkages in their repeating units, they still exhibit moderately high thermal stability and show no obvious weight loss before 400 °C. The introduction of bromine on the polymer backbone caused a decrease of inherent viscosity, crystallinity, and thermal stability of the polyarylates, while causing an increase in glass transition temperature and a great enhancement of fire retardancy.     

Preparation and thermotropic properties of copoly(4,4′-biphenylene sebacate-co-eicosanedioate)s

Summary A series of thermotropic copoly(4,4-biphenylene sebacate-co-eicosanedioate)s were prepared by melt polycondensation of 4,4-biphenylene diacetate, sebacic acid and eicosanedioic acid. Their thermal transitions and liquid crystalline properties were investigated by DSC and polarized micrrocope. The copolyesters were found to exhibit a smectic phase, but no nematic phase was observed upon cooling. The smectic-isotropic transition temperature decreased as the content of eicosanedioate unit increased, and the corresponding transition heat did not change to a great extent. However, the crystalline-smectic transition temperature showed an eutectic behavior, and the crystalline-smectic transition heat was depressed considerably after copolymerization. The X-ray diffraction data of the copolyesters after thermal treatment were measured and compared with the thermal properties measured by DSC.