Diaminodiphenyl Ether Research Articles

Fabrication and Dielectric Characterization of a Novel Polyimide

A novel polyimide (PI) films with three kinds of monomers was synthesized in this paper. The polyimide unit is derived from Pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride, (BTDA), and 4,4, -diaminodiphenyl ether (ODA). The dielectric properties of the films were measured. The dielectric spectra show that dielectric constant is about 3.7, which is larger than the PI with two kinds of monomers. In addition, the loss tangent and conductivity of the films is quite small, which is important for the practical use of them.

A Polyamic Acid from Pyromellitic Dianhydride and Diaminodiphenyl Ether for Thickening Leather and Reducing Chromium Offer in Tannage

A polyamic acid suitable for either pretanning or retanning wet-blue in leather industry has been synthesized by polycondensing pyromellitic dianhydride with diaminodiphenyl ether. Its performances for improving physical properties of crust leather, reinforcing absorption and fixation of chromium were investigated by applying it in a reduced chromium offer system. The results show that the extension and tearing strength, especially thickness of crust leather can be significantly improved by the polyamic acid, and residual chromium in spent tanning bath could be reduced to below 40 mgCr+3/l by pretanning with the polyamic acid. The chromium released from wet-blue during fatliquoring can be reduced by 85.7%, and kept at a much lower limit of 6 mg/l by the polyamic acid. A much fuller crust leather with shrink temperature of over 95°C can be obtained with 3% of normal chrome powder by pretannig or retanning with the polyamic acid. Therefore, this polyamic acid has the good potential for industrial application in ecological leather.

Curing properties of novel curing agent based on phenyl bisthiourea for an epoxy resin system

Phenyl bisthioureas: 4,4′-(bisthiourea)diphenylmethane (DTM), 4,4′-(bisthiourea)diphenyl ether (DTE), and 4,4′-(bisthiourea)diphenyl sulfone (DTS) were synthesized and used as curing agents for the epoxy resin diglydicyl ether bisphenol A (DGEBA). Synthesized phenyl bisthioureas were characterized using FT-IR and 1H-NMR analysis. For comparison studies the epoxy system was also cured using the conventional aromatic amine 4,4′-diaminodiphenyl ether (DDE). Curing kinetics of epoxy/amine system was studied by dynamic and isothermal differential scanning calorimeter (DSC). Curing kinetic was evaluated based on model-free kinetics (MFK) and ASTM E 698 model, and the activation energy was compared with DDE. Curing system of phenyl bisthiourea link (DGEBA/DTM, DGEBA/DTE, and DGEBA/DTS) shows two exothermic peaks, while that of the conventional aromatic amines showed only a single peak. The initial exothermic peak is due to the primary nitrogen of the thiourea group, and the exotherm at higher temperature is due to the presence of thiourea groups. Glass transition temperature (Tg) of DGEBA/DTM, DGEBA/DTE, and DGEBA/DTS cured resins were lowered by 323 K when compared to the widely used diaminodiphenyl ether (DDE) cured resin. Oxidation induction temperature measurement performed on DSC suggests that the DGEBA/DTM, DGEBA/DTE, and DGEBA/DTS system cured resins has better oxidative stability when compared to cured DGEBA/DDE resin system.

Development and characterization of co‐polyimide/attapulgite nanocomposites with highly enhanced thermal and mechanical properties

A series of co‐polyimide/attapulgite (co‐PI/AT) nanocomposites have been successfully fabricated from anhydride‐terminated polyimide (PI) and γ‐aminopropyltriethoxysilane (APTES)‐modified fibrous attapulgite (AT). Co‐PI was prepared from 4,4′‐diaminodiphenyl ether (ODA), 4,4′‐oxydiphthalic anhydride (ODPA), and 2,2‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) by using the method of chemical imidization. Different amount of AT (0, 1, 3, 5, 7 wt%) were introduced into co‐PI via strong covalent interactions between terminal anhydride and amino groups. The properties of co‐PI/AT nanocomposites such as morphology, thermal stability, mechanical properties, and UV transparency were investigated to illustrate the contribution of the introduction of AT into the PI matrix. FTIR spectra and SEM images revealed that network structures between co‐PI and AT are formed, which endowed the nanocomposites with outstanding thermal and mechanical properties. The co‐PI/AT nanocomposites exhibited excellent thermal and thermo‐oxidative stabilities with the onset decomposition temperature and 10% weight loss temperature increasing to the ranges of 502–510°C and 555–562°C from 480°C to 526°C for the pristine co‐PI, respectively. The glass transition temperatures of these co‐PI/AT nanocomposites increased to the range of 231–238°C from 222°C for pure co‐PI. The co‐PI/AT nanocomposites films were found to be transparent, flexible, and tough. By incorporating 5 wt% AT into the co‐PI matrix, the tensile strength, elongation at break, and Young's modulus of the co‐PI/AT nanocomposites reached 110.7 MPa, 14.5%, and 1.2 GPa, respectively, which are 50%, 120%, and 80% increased compared with the values of pristine PI. POLYM. COMPOS., 35:86–96, 2014. © 2013 Society of Plastics Engineers

Synthesis and properties of novel copolymers of poly(ether ketone diphenyl ketone ether ketone ketone) and poly(ether amide ether amide ether ketone ketone)

New monomers, 4,4′‐bis(4‐phenoxybenzoyl)diphenyl (BPOBDP) and N,N′‐bis(4‐phenoxybenzoyl)−4,4′‐diaminodiphenyl ether (BPBDAE), were conveniently synthesized via simple synthetic procedures from readily available materials. Novel copolymers of poly(ether ketone diphenyl ketone ether ketone ketone) (PEKDKEKK) and poly(ether amide ether amide ether ketone ketone) (PEAEAEKK) were synthesized by electrophilic Friedel‐Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of BPOBDP and BPBDAE, over a wide range of BPOBDP/BPBDAE molar ratios, in the presence of anhydrous AlCl3 and N‐methylpyrrolidone (NMP) in 1,2‐dichloroethane (DCE). The copolymers obtained were characterized by different physico‐chemical techniques. The copolymers with 10–40 mol% BPBDAE are semicrystalline and had remarkably increased Tgs over commercially available PEEK and PEKK due to the incorporation of amide and diphenyl linkages in the main chains. The copolymers IV and V with 30–40 mol% BPBDAE had not only high Tgs of 185–188°C, but also moderate Tms of 326–330°C, having good potential for the melt processing. The copolymers IV and V had tensile strengths of 101.7–102.3 MPa, Young's moduli of 2.19–2.42 GPa, and elongations at break of 13.2–16.6% and exhibited high thermal stability and excellent resistance to organic solvents. POLYM. ENG. SCI., 54:1757–1764, 2014. © 2013 Society of Plastics Engineers

Synthesis, Characterisation and Fluorescence Studies of New Bis-Phenanthrimidazole Derivatives

The synthesis of new bis-phenanthrimidazole derivatives in one-pot four-component reaction from 9,10-phenanthra-quinone, aromatic aldehydes, 4,4'-diaminodiphenyl ether and ammonium acetate is described. These new compounds were subsequently studied for their fluorescence properties.

New thermally stable poly(amide-imide)/montmorillonite reinforced nanocomposite based on N,N′-pyrromellitoyl-bis-l-valine: synthesis and characterization

Abstract Two new samples of poly(amide-imide) (PAI)/nanocomposites reinforced montmorillonite containing N,N′-pyrromelitoyl-bis-l-valine moiety in the main chain were synthesized by a solution intercalation technique. PAI 3 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N,N′-pyrromelitoyl-bis-l-valine 1 with 4,4′-diamino diphenyl ether 2 in the presence of triphenyl phosphite, CaCl2, pyridine and N-methyl-2-pyrrolidone. The morphology and structure of the resulting PAI-nanocomposite films 4a and 4b with 5% and 10% silicate particles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-visible spectroscopy, thermogravimetric analysis and differential scanning calorimetry.

Dramatic enhancement of carbon nanotube dispersion in polyimide composites by a two-step amino functionalization approach

Amino modified multiwall carbon nanotubes (MWNTs) are prepared, respectively, by two ways: the conventional one-step method that directly treats acyl chloride functionalized MWNTs with 4, 4′-diaminodiphenyl ether (ODA), giving the amino modified MWNT (Di-MWNT), as well as an improved two-step method in which acyl chloride functionalized MWNT react with mono-Boc protected ODA first and then the Boc-groups are deprotected to provide the amino modified MWNT (NH2-MWNT). Anhydride-terminated polyimide (PI) composite films based on NH2-MWNT and Di-MWNT are fabricated by solution blending and consequent planar casting. The exposed amino groups of NH2-MWNT create strong covalent bonds with the anhydride-terminated polyamide acid in the course of N-acylation and curing chemical reactions. Solubility examinations of nanotubes and morphologies of the composite films indicate that the dispersion of NH2-MWNT is significantly better than Di-MWNT in PI matrix and NH2-MWNT can form connected network throughout the PI matrix which makes the NH2-MWNT/PI film presenting superior conductivity. Both morphologies and mechanical properties of the composites show that NH2-MWNT has stronger interfacial interaction with the PI matrix. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3449–3457

Processing of Thermally Stable Polymer Nanocomposites Reinforced Silicate Nanoparticles Based on N-trimellitylimido-L-phenyl alanine

Abstract In this article two polymer/nanocomposite films with 5 and 10% silicate particles based on Poly(amide-imide) (PAI) from N-trimellitylimido-L-phenyl alanine were prepared via solution intercalation method through blending of organoclay with the PAI solution. Poly(amide-imide) was synthesized by the direct polycondensation reaction of N-trimellitylimido-L-phenyl alanine with 4,4′-diamino diphenyl ether in the presence of triphenyl phosphite (TPP), CaCl2 and pyridine (Py). Morphology and structure of the resulting PAI-nanocomposite films were characterized by FTIR spectroscopy, X-ray diffraction and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using Uv-vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements.

Dynamic DSC curing kinetic study of epoxy resin of 1,3‐bis(4‐hydroxyphenyl) prop‐2‐en‐1‐one using aromatic diamines and phthalic anhydride

AbstractEpoxy resin of 1,3‐bis(4‐hydroxyphenyl)prop‐2‐en‐1‐one has been synthesized and studied its cure kinetics by differential scanning calorimetry at four different heating rates in nitrogen atmosphere and varying proportions of 4,4′‐diaminodiphenyl ether, 4,4′‐diaminodiphenyl sulfone and phthalic anhydride. The energy of activation (Ea) and pre‐exponential factor (A) has been determined according to Flyn‐Wall‐Ozawa method at various degrees of cure ranging from 0.1 to 0.9. The derived results are discussed in light of effect of hardeners concentrations, heating rates, degree of cure, and nature of hardeners, etc. The structure of the hardeners and their concentrations affected the cure behavior. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Effect of the adding of rod-like attapulgite upon the properties of polyimides produced by random copolycondensation

A series of polyimides (PIs) and polyimide/attapulgite (AT) composite films was successfully prepared by random copolycondensation. The polyimides were synthesized based on 4,4′-diaminodiphenyl ether, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), and 4,4′-oxydiphthalic anhydride (ODPA). By adjusting the ratio of BPADA and ODPA, three different types of anhydride group-terminated PIs were obtained. AT was functionalized by chemical modification with γ-aminopropyltriethoxysilane and then chemical bonded with PI via reaction between amino group and anhydride group, resulting in stable PI/AT composites. The structure and properties of PIs and PI/AT composites were characterized by FTIR, XRD, TG, SEM, DSC, DMA, mechanical measure, and so on. Comparison was given between PIs and PI/AT composites. Results showed that all PIs had good thermal stability and mechanical properties with glass translation temperature (T g) over 210 °C, 5 % weight loss temperature (T d,5%) over 494 °C and tension strength of 84–89.9 MPa, breaking elongation around 7 %. More stable, flexible, and much stronger films were obtained after adding 5 wt% AT, which showed 535–548.5 °C, 85.8–118.9 MPa, and 10.3–24.7 % in T d,5%, tension strength, and breaking elongation, respectively. Much interestingly, we found that AT had the greatest effect on PI-2, the yielding of which occurred during mechanical measure, and PI/AT-2 composite displayed excellent comprehensive properties.

Thermal Stabilities and Mechanical Properties of Two Tetra-Functional Epoxy Resins

To study the relationship between the molecular main chain structure and the properties of amine based tetra-functional epoxy resins, especially for the thermal stabilities and the mechanical properties, N,N,N',N'-Tetraglycidyl-2,2-Bis[4-(4-aminophenoxy)phenyl]propane (TGBAPP) and N,N,N',N'-Tetraglycidyl-4,4'-diamino diphenyl ether (TGDDE) were cured with Methyl nadic anhydride (MNA). The thermal behavior of the cured epoxy resins were studied with the thermo-gravimetric analysis (TGA), and the glass transition temperature (Tg) were determined with the Dynamic Mechanical Analysis (DMA). Additionally, the mechanical properties of them were tested. The results indicated that the cured epoxy resin based on TGBAPP had better thermal stabilities and toughness.

Synthesis and properties of novel random copolymers of poly(ether ketone ether ketone ketone)–poly(ether ketone imide)

Bis[4-(p-phenoxybenzoyl)-1,2-benzenedioyl]-N,N,N',N'-4,4'-diaminodiphenyl ether (BPBDADPE) was prepared by the Friedel-Crafts acylation reaction of diphenyl ether (DPE) with bis(4-chloroformyl-1,2-benzenedioyl)-N,N,N',N'-4,4'-diaminodiphenyl ether (BCBDADPE). Novel random copolymers of poly(ether ketone ether ketone ketone)(PEKEKK)–poly(ether ketone imide)(PEKI) were synthesized by the modified electrophilic Friedel-Crafts copolycondensation of terephthaloyl chloride (TPC) with a mixture of 4,4'-diphenoxybenzophenone (DPOBPN) and BPBDADPE, over a wide range of DPOBPN/BPBDADPE molar ratios, in the presence of anhydrous aluminum chloride and N-methylpyrrolidone (NMP) in 1,2-dichloroethane (DCE). The random copolymers with 10–40 mol% BPBDADPE are semicrystalline and had much higher T gs than those of the conventional PEEK and PEKK due to the incorporation of imide linkages in the main chains. The copolymers IV and V with 30–40 mol% BPBDADPE had not only high T gs of 185–188 °C, but also moderate T ms of 338–340 °C, having good potential for melt processing. The copolymers IV and V had tensile strengths of 102.1–105.3 MPa, Young’s moduli of 2.22–2.43 GPa, and elongations at break of 14.1–15.9 % and exhibited high thermal stability and good resistance to organic solvents.

Comparative studies on melt processable polyimides derived from 2,3,3′,4′-oxydiphthalic anhydride and 2,3,3′,4′-thioetherdiphthalic anhydride

Two thermoplastic polyimides were controllably synthesized with similar molecular weight from 2,3,3′,4′-oxydiphthalic anhydride (3,4′-ODPA) or 2,3,3′,4′-thioetherdiphthalic anhydride (3,4′-TDPA) with 4,4′-diaminodiphenyl ether (ODA) by a one-step method of m-cresol. The solubility and mechanical properties of these polymers were investigated for comparison. The thermal and melt processable properties of these polymers were examined carefully by differential scanning calorimetry, thermogravimetric analysis (TGA), rheometer and melt index, and so on. It was found that the glass transition temperature ( Tg) of 3,4′-TDPA/ODA was about 15°C lower than that of 3,4′-ODPA/ODA, the melt indices of 3,4′-TDPA/ODA at different temperatures were higher than those of 3,4′-ODPA/ODA, while the minimum melt viscosity of 3,4′-TDPA/ODA was lower than those of 3,4′-ODPA/ODA. Furthermore, TGA results showed that 3,4′-TDPA/ODA had different degradation mechanism in air compared with 3,4′-ODPA/ODA. The long-term thermooxidative stability results showed that 3,4′-TDPA/ODA had better thermal oxidative stability than 3,4′-ODPA/ODA at 410°C for 6 h in air, which could be associated with the results of apparent activation energy ( Ea) of polymers calculated by TGA dynamics. The natural bond orbital charge of ethero atoms (S or O), and energy gap of the corresponding model compounds were also obtained by computational simulation to correlate with polymer properties.

Synthesis and Characterization of Polyimide from 4,4’-Diamino diphenyl ether having Substituents at 2,2’-position

Synthesis and Characterization of Polyimide from 4,4’-Diamino diphenyl ether having Substituents at 2,2’-position

Processability Improvement of Polyimide by Adding Asymmetric Structure in Molecular Chain

A series of high-strength and processable polyimide(PI) moulding compounds with different content of diamine was prepared from 3,3′,4,4′-biphenyl tetracarboxylic diandhydride(BPDA) and 4,4′-diaminodiphenyl ether(4,4′-ODA),3,4′-diaminodiphenyl ether(3,4′-ODA) through chemical imiidization.The rheological,mechanical and thermal resistance properties of the PI moulding compounds were investigated.With the increasing of 3,4′-ODA content,the impact strength of the PI could be maintained without dramatic change.The rheological properties of the PI were enhanced and the glass transition temperature can reach 275 ℃.The impact strength of the PI is about 141 kJ/m2.Processability of the PI is superior at 20 MPa.

Reversible Phase Transformation and Luminescence of Cadmium(II)-Dipyridylamide-Based Coordination Frameworks

We have synthesized a series of 1D double-zigzag ({[Cd(paps)(2)(H(2)O)(2)](ClO(4))(2)}(n) (1), {[Cd(papo)(2)(H(2)O)(2)](ClO(4))(2)}(n) (3), and {[Cd(papc)(2)(H(2)O)(2)](ClO(4))(2)}(n) (5)) and 2D polyrotaxane frameworks ([Cd(papc)(2)(ClO(4))(2)](n) (6)) by the reaction of Cd(ClO(4))(2) with dipyridylamide ligands N,N'-bis(pyridylcarbonyl)-4,4'-diaminodiphenyl thioether (paps), N,N'-bis(pyridylcarbonyl)-4,4'-diaminodiphenyl ether (papo), and N,N'-(methylenedi-p-phenylene)bispyridine-4-carboxamide (papc), respectively, where their molecular structures have been determined by X-ray diffraction studies. Based on the powder X-ray data (PXRD) of compound 3 and its Zn(II) analogue, heating the double-zigzag framework of compound 3 can give the polyrotaxane framework of [Cd(papo)(2)(ClO(4))(2)](n) (4) and grinding this powder sample in the presence of moisture resulted in its complete conversion back into the pure double-zigzag framework. In addition, heating the double-zigzag frameworks of compounds 1 and 5 can induce structural transformation into their respective polyrotaxanes, whereas grinding these solid samples in the presence of moisture did not lead to the formation of the double zigzags. Herein, we investigated the effect of the metal (from Zn(II) to Cd(II)) on the assembly process and luminescence properties, as well as on the particularly intriguing structural transformation of a series of papx-based frameworks. In fact, the assembly behavior and luminescence properties of the Cd(II)-papx and Zn(II)-papx frameworks were really similar. However, both Zn(II)-papx (x = s, o) frameworks can perform reversible structural transformation, but only the Cd(II)-papo framework can do it. Therefore, a delicate metal effect on such a new structural transformation can be observed.

New poly(ether-amide-imide) reinforced layer silicate nanocomposite: Synthesis and properties

A new series of poly(ether-amide-imide)/organoclay were generated through solution intercalation technique. Cloisite® 20A was used as a Modified montmorillonite for ample compatibilization with the PEAI matrix. The poly(ether-amide-imide) (PEAI) 3 chains were synthesized by the direct polycondensation reaction of N,N′-(4,4′-diphenylether)bistrimellitimide 1 with 4,4′-diamino diphenyl ether two in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PEAI-nanocomposite films 3a–3b with (5–10wt%) silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposite films were investigated by using UV–Vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements.

Novel latent epoxy curing agent for secondary insulation in electrical rotors and stators

A novel multifunctional epoxy curing agent 2-((4-(4-aminophenoxy) phenylamino) (4- hydroxyphenyl)hydrazine carbothioamide(APHCTA)) containing phenolic, thiourea, primary and secondary amines was synthesized by condensation technique and characterized using FTIR, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> H NMR, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> C NMR spectroscopy. Thermal and curing studies were performed using Thermogravimetric analyzer (TGA) and Differential scanning calorimeter (DSC) respectively. The new compound was used as a curing agent for thermosetting epoxy resin Diglycidyl ether of Bispheol-A (DGEBA). The in built phenolic moiety accelerates the curing rate along with the amines thereby relatively lowering the curing temperature compared to the commercial aromatic curing agent such as diamino diphenyl ether (DDE) and also gives longer pot life compared to aliphatic amine such as triethyltriamine (TETRA). Cured polymer of DGEBA/APHCTA showed lower glass transition temperature(Tg) which imparts the flexibility and it also exhibits good thermal stability up to 340 °C. Activation energy (Eα) based on model free kinetics (MFK) method indicates the extent of curing of the reaction. Isothermal curing thermogram showed that the resin cures at lower temperature. Electrochemical Impedance study for the cured film of DGEBA/APHCTA coated on the copper plate exhibits good corrosion inhibition. The new curing agent containing amines, phenolic and thiourea is a potential candidate for use as a latent curing agent for single part epoxy resin for impregnation of AC motor rotors and stators.

Highly soluble phenylethynyl-terminated imide oligomers based on KAPTON-type backbone structures for carbon fiber-reinforced composites with high heat resistance

Novel addition-type phenylethynyl-containing imide oligomers (degree of polymerization: n=1–10) derived from 1,2,4,5-benzenetetracarboxylic dianhydride or pyromellitic dianhydride (PMDA), 2-phenyl-(4,4′-diaminodiphenyl ether) (p-ODA) and 4-phenylethynylphthalic anhydride (PEPA) were prepared and evaluated as a matrix resin for high heat-resistant carbon fiber-reinforced composites. The uncured imide oligomers showed good solubility (>30 wt%) in N-methyl-2-pyrrolidone and very low melt viscosities. These imide oligomers were successfully converted to crosslinked structures after curing at 370 °C. The glass transition temperature (Tg) and the elongation at break (ɛb) of the cured imide resin were found to be excellent (almost 340 °C and >15%, respectively). The carbon fiber prepreg was prepared from the imide oligomer solution and used to fabricate void-free laminates with high Tg. The thermal and mechanical properties of the laminates were determined at ambient temperature.