Diaminodiphenyl Sulphone Research Articles

Low‐temperature processable glass fiber reinforced aromatic diamine chain extended bismaleimide composites with improved mechanical properties

AbstractThe synthesis of 4,4′‐bismaleimido diphenylmethane (BMIM) and modified BMIM by its chain extension using commercially available aromatic diamines like 4,4′‐diamino diphenyl methane (DDM), 4,4′‐diaminodiphenyl sulphone (DDS), and 4,4′‐diamine diphenyl ether (DDE) was done. The synthesized materials have been characterized for structural aspects using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). The structure of BMIM was confirmed due to the presence of specific bands at ~1400 and 1705 cm−1 responsible for CC and OCNCO groups, respectively. The reduction in the heat of fusion and enthalpy of curing for chain extended bismaleimides/modified BMIM shows the influence of the swivel group in diamine during curing. The curing window has broadened for BMIM_M and BMIM_E by ~40°C and narrowed for BMIM_S by ~100°C. The mechanical properties and the chemical resistance were studied for the composites made from the BMIM and modified BMIM based composites. Fiber‐enhanced modified bismaleimide resin has improved mechanical properties.

Mechanical responses of epoxy/cloisite nanocomposites

Polymeric nanocomposites based on nanoclay are extensively utilized in various structural applications. In this work, the effect of organically modified nanoclay (cloisite 20A) on the chain confinement, mechanics, structure, and thermal properties of epoxy resin cured with diamino diphenyl sulphone (DDS) was analysed. The viscoelastic properties were analysed by dynamic mechanical analysis (DMA). The stiffness parameter and the peak parameters from loss modulus and tan δ indicate effective adhesion of nanoclay with the polymer matrix. The filler-matrix confinement has created a constrained zone around the polymer-matrix interface resulting in the immobilization of polymer chains near the fillers. The chain confinement was determined from tan δ curve. The heterogeneity of the cloisite 20A/epoxy nanocomposites was analysed by Cole-Cole plots. Fine dispersion of cloisite 20A was achieved by intercalation of nanoclay as observed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. Finally, the thermal properties of the nanocomposites were analysed by thermogravimetric analysis (TGA).

Anion Induced Fluorescence Quenching of Various Aromatic Amino Fluorophores

Fluorescence quenching of 2-amino7-bromofluorine (2ABF) and 4,4-diaminodiphenyl sulphone (4DADPS),) ] by inorganic anions Cl-, Br–, SO42– SO32–, S2O32–, CO32–, NO3–, & HPO42– have been studied in 95% (v/v) water–ethanol mixture medium..The quenching was found to be dynamic in all systems. The plots of log kq values with singlet transition energy (Es) of the fluorophore and with ECTTS of the quencher are linear indicating the presence of electron-transfer quenching mechanism. ΔGTH values for charge transfer quenching have been determined for aminodiphenylsulphone.

OPTICAL, STRUCTURAL, THERMAL AND MORPHOLOGICAL CHARACTERIZATION OF 4, 4’- DIAMINODIPHENYL SULPHONE/TITANIUM DIOXIDE/MULTIWALLED CARBON NANOTUBE NANOCOMPOSITES

Polymeric nanocomposites based on electroactive conductive polymers with nanoparticle fillers have won considerable attention in recent years due to its highly desirable multifunctional characteristics. In the present study, 4, 4’- diaminodiphenyl sulphone has been polymerized and composites were prepared by adding TiO2 and multiwalled carbon nanotube to the polymer by magnetic stirring. These nanocomposites have been characterized using analytical techniques such as UV-Vis, FT-IR, XRD, FE-SEM, EDS and TGA/ DTA analysis. The incorporation of multiwalled carbon nanotube and titanium dioxide in poly 4, 4’-diaminodiphenyl sulphone has been endorsed by FT-IR analysis. It showed that the peak at 453, 431 cm- 1 confirms the stretching vibration of the Ti-O bond of TiO2 and the absorption peaks at 2925 and 2283 cm-1 are imputed to symmetrical telescopic vibrations of the methylene group (-CH2-) of carbon nanotubes. This confirms the incorporation of TiO2 and multi-walled carbon nanotubes into the polymer matrix in the prepared nanocomposites. The XRD pattern showed formation in the nanoscale range (5.94 nm). SEM analysis showed that the variation in polymer morphology depended mainly on titanium dioxide and multi-walled carbon nanotubes.

Study of the acoustic emission response to a core-shell rubber-toughened, high-temperature composite

This work explores the effect of core-shell rubber (CSR) addition on the cure reaction and resulting mechanical and thermal properties of a highly cross-linked network made from 4,4′- tetraglycidyl diamino diphenyl methane and 3,3′-diamino diphenyl sulphone. Up to 20 wt% of a CSR rubber, composed of a soft polybutadiene core and a hard poly methyl methacrylate (PMMA) shell was dispersed in the epoxy/amine and after cure was found to increase the glass transition temperature and thermal degradation temperatures modestly, while reducing the char yield. Flexural properties also reduced with CSR addition, although fracture toughness (KIC) was increased by 45% at 20 wt% of CSR. Furthermore, the fracture strain energy release rate (GIC) of the corresponding carbon fibre composite at the same CSR concentration, increased by almost 115%. Acoustic emission spectroscopy is introduced as a tool for investigating crack propagation during mode I loading and identifying any differences in the failure mechanism between the unmodified and the 20 wt% CSR-modified carbon fibre composites.

Synthesis of tri‐aryl ether epoxy resin isomers and their cure with diamino diphenyl sulphone

AbstractThe synthesis of bi‐ and tetra‐functional tri‐aryl ether epoxy resin isomers and their subsequent cure with 44 diamino diphenyl sulphone (DDS) is presented here. The effect of varying aromatic substitution and cross‐link density on the structure, property, and processing relationships is explored for 1,3 bis(3‐glycidyloxyphenoxy)benzene (133 BGOPB), 1,4 bis(4‐glycidyloxyphenoxy)benzene (144 BGOPB), N,N,N,N‐tetraglycidyl 1,3‐bis (3‐aminophenoxy) benzene (133 TGAPB), and N,N,N,N‐tetraglycidyl 1,4‐bis (4‐aminophenoxy) benzene (144 TGAPB). Meta substitution to the aromatic ring reduces the rate of reaction, glass transition temperature, yield strain and crosslink density, coefficient of thermal expansion, and side reactions, while increasing strain softening, compressive modulus and strength, and methyl ethyl ketone ingress. Increasing crosslink density increases the glass transition temperature, promotes side reactions during cure, and increases compressive modulus, strength, and yield strain, while reducing coefficients of thermal expansion, methyl ethyl ketone ingress, and density. The results are discussed in terms of packing efficiency of the meta‐substituted epoxy resins and the role of short range molecular mobility caused by the lack of an aromatic axis of rotation.

Template free one pot synthesis of heteroatom doped porous Carbon Electrodes for High performance symmetric supercapacitor

Carbon materials with favourable porous architecture and heteroatom functionalities are well considered for energy storage applications due to its excellent structural and electrochemical properties. In this paper solid-state symmetric supercapacitor (SC) using heteroatom (nitrogen and oxygen) inherently co-doped microporous carbon (HMC) was investigated. HMC was prepared by simple carbonization method without any additives by adopting multistep experimental procedures. 4, 4′-diamino-diphenyl sulphone (DDS) was pyrolyzed at 950 °C in a single step and HMC with surface area of 1766 m2 g−1 and a total pore volume of 0.87 cm3 g−1 was obtained. The structural characteristics and the content of heteroatom functionalities were manipulated with pyrolysis time to improve the elctrochemical behaviour. The symmetrical SC was fabricated with polyvinyl alcohol (PVA) supported 6 M KOH and 1 M Na2SO4 as gel electrolytes. The performance of solid-state SC showed good cycling stability and high energy density. The device exhibited a maximum energy density of 35 W h kg−1 with a maximum power density of 3180 W kg−1 remained stable (91% capacity retention) after 5000 cycles. Finally, the device using porous carbon electrode material with PVA+1 M Na2SO4 able to light a LED after charging for about 5sec.

Modern History of Hansen's Disease in Korea.

Modern history of Hansen's Disease (HD) in Korea begins with nationwide use of the chemotherapeutic agent Diamino Diphenyl Sulphone for the patients in 1955. Definition of the case was different from time to time. Based on World Health Organization (WHO) criteria, Ministry of Health and Welfare (MOHW) reported 4,393 registered patients and same number 4,393 as new cases in 1977. This is the turning point they accepted patient reporting system of WHO, but total number of registered and managed as leprosy patients was 28,029 in 1977, which means the people who needs HD service from government at that time. The number of new cases decreased from 4,393 in 1977, 39 in 1996 to 4 in 2017. Regarding to new cases, it takes 40 years to accomplish from thousands level to below 10. Now we have 166 active cases (registered patients) and reported them as patients to the WHO. Korea Civil Assistance Command invited Dr. RG Cochrane who visited Korea for six weeks to make blue print for eradication of HD in Korea. With his advice and MOHW set HD project and plan for manpower to solve HD problems in 1955. Dr. Joon Lew and his colleagues founded Korean Leprosy Prevention Association in 1947 to combat leprosy, enlighten the public, and solve social problems caused by HD. The Korean Leprosy Prevention Association led by him changed its name to the Korean Leprosy Association in 1956, and grew into the current Korean Hansen Welfare Association. This organization is now playing a leading role in the eradication and management of HD in Korea.

Effect of aromatic substitution on the kinetics and properties of epoxy cured tri‐phenylether amines

ABSTRACTThe reaction kinetics and structure property relationships of isomeric tri‐aromatic ether‐linked amines based on the structure bis (aminophenoxy) benzene, cured with diglycidyl ether of bisphenol F (BisF) are investigated in this study. Reaction kinetics are explored using rheological and calorimetric measurements, whereas structure property relationships are determined from their flexural properties, dynamic mechanical properties (DMTA), and thermogravimetric analysis (TGA). A BisF network cured with 4,4 diamino diphenyl sulphone (44 DDS) is used as a benchmark to represent a commercially available high‐performance resin system. Varying the substitution of the ether linkages on the aromatic groups from ortho, meta to para was found to have a significant impact on reactivity and network properties after cure. The variations are explained in terms of inductive and resonance effects primarily acting on the outer aromatic rings. Interestingly, however, these same effects acting on the central aromatic ring also impact upon reactivity despite their proximity from the amines. Mechanical and thermal properties are explained by changes in the short‐range molecular mobility within the network architecture such as phenylene rotations or π flips and are experimentally validated from the breadth and position of the subambient γ relaxations. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47383.

Modelling the properties of a difunctional epoxy resin cured with aromatic diamine isomers

Group Interaction Modelling has been extended to predict a range of thermo-mechanical properties of diglycidyl ether of bisphenol A cured with two isomers of diaminodiphenyl sulphone. The meta-meta and para-para positions of the substituents on the phenylene rings in the curing agent cause differences in packing efficiency, reaction kinetics and conformational freedom. Experimental data in the form of dynamic mechanical, static mechanical and density measurements are acquired in order to provide validation for the model. The model has proven capable of accurately reproducing the experimental measurements to well within experimental errors in most cases. Both the experimental measurements and model predictions have highlighted a number of subtle differences in behaviour of the resins cured with the two diamine isomers. In particular, variation of the amine/epoxy ratio has revealed how the secondary phase transitions of the resins are influenced. Variation of the glass and beta transitions in amine rich, stoichiometric or epoxy rich mixtures is described in terms of the molecular motions responsible for the transitions and the underlying network structural differences between the meta and para isomers.

Effect of organically modified clay on the morphology, rheology and viscoelasticity of epoxy –thermoplastic nanocomposites

The effect of cloisite 20A clay on rheology and dynamic mechanical properties of epoxy and poly-(styrene-co-acrylonitrile) (SAN) blend system cured with diamino-diphenyl sulphone (DDS) was investigated. The effect of modified clay (cloisite 20A) on two different compositions of initially miscible epoxy/SAN system has been investigated based on the differences in the mechanism of phase separation during curing. The dynamics of phase separation was followed by optical microscopy coupled with a heating stage. The developed microstructures obtained after complete curing were examined by scanning electron microscopy (SEM) after preferential etching of SAN phase with dichloroethane. The processing parameters occurring during the curing reaction was analyzed by dynamic in-situ rheometry. The viscoelastic properties of fully cured blends and composites were further determined by dynamic mechanical analysis (DMA). Localization of filler among the blend phases was established from dynamic mechanical analysis.

Internal antiplasticisation in highly crosslinked amine cured multifunctional epoxy resins

The aromatic epoxy isomers triglycidyl p-aminophenol and triglycidyl m-aminophenol were cured with two aromatic diamine isomers 4,4′ diaminodiphenyl sulphone and 3,3′ diaminodiphenyl sulphone, creating four variations of epoxy resin. Dynamic and static mechanical analyses were used to understand the influence of chemical and network structure on the thermal, volumetric and mechanical properties of the epoxy resin. Fracture toughness increases are observed for networks containing meta substituted phenylene ring amines compared to the para equivalents, however no difference is noticed when the meta substituted phenylene ring epoxy is used. Use of meta substituted phenylene rings increases glassy modulus, yield stress, density and strain to failure. Correspondingly, decreases are seen in the glass transition temperature, intensity of the beta transition and the rubbery modulus. The results are entirely consistent with internal antiplasticisation caused by the presence of the meta substituted phenylene rings.

Design-Syntheses, Characterization and Biological Activity Studies of Azobenzen-P,Pꞌ-Di(3,1-Benzoxazin-4-One-2yl) and Azobenzen-P,Pꞌ-Di[(3- Substituted 3(4H)Quinazolinone-2yl] Derivatives

Sixteen azobenzene-p,pežŒ-di[3-substituted-4(3H)quinazolinone-2yl] were synthesized from reaction of azobenzenp, pežŒ-di(3,1-benzoaxzin-4-one-2yl) with amino-moieties nucleophlies, like hydrazinehydrate, hydroxylamine, p,toluidine, p-aminobenzene sulphonamide, 2-pyrimidine, 5-nitro-2-aminopyridine, ethyleneamine,5-(p-bromo) phenyl-2-aminothiazol, p,pežŒ-diamino diphenyl sulphone, quinidine hydrochloride, urea, thiourea, 3,5-dimethyl- 2-phenyl-4-aminopyrazolin-3-one, N(5-methyl-3-isoxazolyl)-p-aminobenzen sulphonamide, semicarbazide and thiosemicarbazide, in a molar ratio (1:2) respectively. azobenzen-p,pežŒ-di(3,1-benzoaxzin-4-one-2yl), was synthesized by following serial synthetic pathway. Reductive-condensation of p-nitrobenzoic acid in basic media give azobenzenp, pežŒ-dicarboxylic acid, then treated with thionyl chloride to give azobenzen-p,pežŒ-diacid chloride. It condensed with anthranilic acid to give azobenzen-p,pežŒ-[(dibenzoic acid-2yl)dicarboxamide], upon treatment with thionyl chloride give azobenzen-p,pežŒ-di(3,1-benzoaxzin-4-one-2yl). All synthesized compounds characterized by FTIR, 1HNMR, 13CNMR and mass spectral analyses. All synthesized azobenzen-p,pežŒ-di(3,1-benzoaxzin-4-one-2yl), and sixteen azobenzenep, pežŒ-di[3-substituted-4(3H)quinazolinone-2yl] compounds, were examined as antibacterial agents against gm(+ve and –ve) bacteria, and antifungal agents. Results showed abroad extended to moderate effects as antibacterial and antifungal agents.

Morphology and Mechanical Properties of Star Block Copolymer Modified Epoxy Resin Blends

In this work, we investigate the morphological and mechanical properties of blends of diglycidyl ether of bisphenol-A (DGEBA) and epoxidized polystyrene–polybutadiene star block copolymer (epST3) using diamino-diphenyl sulphone (DDS) as a hardener. The epoxidation of the star block copolymer was performed using meta-chloroperoxybenzoic acid (m-CPBA). Chemical modification of the copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy while the morphology of the blends was analyzed by microscopic techniques. The mechanical behavior of the blends was analyzed by recording microindentation as well as impact tests. It has been demonstrated that the completely macrophase-separated morphology of the blends could be dispersed into the structures comprising co-continuous networks of the block copolymer phase and the epoxy resin leading to an increment in impact strength. At the same time, the hardness and stiffness of the blends, as shown by the indentation microhardness and indentation modulus, was maintained to a pretty high level.

Synthesis of novel poly 4,4′-diaminodiphenyl sulphone-Fe2O3 nanocomposites for better electrochemical capacitance

A novel poly 4,4′-diaminodiphenyl sulphone (PDDS)–Fe2O3 nanocomposite was synthesized from 4,4′-diaminodiphenyl sulphone in presence of iron oxide nanoparticles by oxidation polymerization using potassium perdisulphate. The solubility performance of PDDS-Fe2O3 nanocomposites exposed better solubility with chloroform, trichloroethylene, N,N-dimethylformamide (DMF) and dimethyl sulphoxide (DMSO). Field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) analyses showed mixed granular nature of the PDDS-Fe2O3 nanocomposites. Energy-dispersive X-ray (EDAX) analysis confirmed the presence of iron oxide nanoparticles in the composites. X-ray diffraction patterns revealed the formation of highly crystalline PDDS-Fe2O3 with ~40-nm size of crystallites. A single absorption peak observed at around 3450 cm-1 is due to the N–H stretching vibration of the imino groups of PDDS-Fe2O3 nanocomposites, and it has revealed the participation of N–H group in the polymerization process. The conductivity of the PDDS-Fe2O3 nanocomposites was determined to be 7.14 × 10-2 S cm-1. The observed capacitance value (256 ± 5 μF) of chemically synthesized PDDS-Fe2O3 nanocomposites has proven their promising application as an energy storage material.

Interfacial and wetting properties of carbon fiber reinforced epoxy composites with different hardeners by electrical resistance measurement

In this research, interfacial and wetting properties of N,N,N,N-tetraglycidyl-4,4-diaminodiphenylmethane (TGDDM) epoxy resin with two hardeners with different chemical structure were evaluated by electrical resistance (ER) measurement. The heat of reaction of TGDDM epoxy with the two different hardeners, 33 and 44 di-amino di-phenyl sulphone (DDS), was analyzed by differential scanning calorimetry (DSC). The TGDDM epoxy exhibited different mechanical properties with the two different DDS hardeners. Combined ER, wetting measurements and the microdroplet test were used for evaluating the spreading effect and interfacial shear strength (IFSS) of carbon fiber (CF) reinforced TGDDM epoxy composites with these different hardeners. The heat of reaction and mechanical properties of TGDDM/DDS were influenced by the chemical structure and different free volumes of the epoxy resins. The relationships between the ER-wetting results and the IFSS were internally consistent. Ultimately it was demonstrated that ER measurements makes it possible to estimate the interfacial and wetting properties of CF reinforced epoxy composites.

Poly(ethylene-co-methacrylic acid) (EMAA) as an efficient healing agent for high performance epoxy networks using diglycidyl ether of bisphenol A (DGEBA)

The use of poly(ethylene-co-methacrylic acid) (EMAA) as an efficient and repeatable thermally activated healing agent in a high performance diglycidyl ether of bis phenol A (DGEBA)/diethyl toluene diamine (DETDA) mendable epoxy composite is presented. Despite curing above the melting point of EMAA (Tm = 85 °C), healing was facilitated by incorporating a preliminary low temperature curing step of 5 h at 80 °C, prior to epoxy cure at 150 °C. Healing was subsequently shown to occur at 130 °C, 150 °C and 200 °C via a pressure delivery mechanism derived from a condensation reaction between EMAA and the residual hydroxyl groups formed during epoxy cure. Healing was repeatable over 5 healing cycles despite a gradual reduction in efficiency, while efficiency increased with increasing healing temperature. Importantly, healing was evident at 130 °C, despite the epoxy network remaining in the glassy state at this temperature (Tg = 150–158 °C). As well as creating high performance mendable composites based upon DGEBA/DETDA, EMAA particles distributed evenly on the surface of the crack plane were found to enhance mode I interlaminar fracture toughness by up to 200% for both DETDA and 4,4 diamino diphenyl sulphone (44 DDS) systems.

Designing dapsone polymer conjugates for controlled drug delivery

Polymer–drug conjugates have significantly influenced polymer therapeutics over the last decade via controlled pharmacokinetics. Dapsone (4,4′-diamino diphenylsulphone) is not only widely used in the treatment of leprosy but forms an essential component in the treatment of autoimmune inflammatory diseases and malaria. However, its low bioavailability and non-specific distribution in the body leads to absorption throughout organs including skin, liver, and kidneys that can cause serious side effects. Thus, in this study we report the synthesis of polymer–drug conjugates of dapsone covalently bonded to macromolecular chains towards the development of new bioactive polymeric formulations with anti-inflammatory properties. Dapsone was functionalised with an acrylic moiety in which the acrylamide residue was directly bonded to one of the aromatic rings of dapsone. This functionalisation yielded an unsymmetrical dapsone methacrylamide (DapMA) structure, which on free radical polymerisation and co-polymerisation with HEMA yielded polymers of hydrocarbon macromolecules with pendant dapsone units. Thermal and size-exclusion chromatographic analysis revealed an increase in thermal stabilisation of the homopolymer (p(DapMA)) in comparison to the copolymer (p(Dap-co-HEMA)) with relatively high average molecular weight. The polymer conjugates exhibited high stability with low dapsone release from the polymeric backbone due to hydrolysis. However, a significant anti-inflammatory activity in a nitric oxide inhibition assay confirmed that this property was the consequence of only the macromolecular composition and not related to the release of low molecular weight compounds. Thus, the conjugation of dapsone to macromolecular systems provides a synthetic route to incorporate this drug into polymeric systems, facilitating their development into new anti-inflammatory therapies. Statement of SignificanceThe dapsone-conjugated methacrylic monomer and polymer derivatives with anti-inflammatory properties described are previously unreported. The scientific impact of this work lies in its potential to expand the clinical applications of dapsone toward the development of advanced anti-inflammatory therapies based on polymer-therapeutic approaches. These approaches facilitate the treatment of existing rare auto-immune and other inflammatory related diseases.

Chemical Synthesis and Characterization of Poly(phenylhydrazine-co-4,4′-diaminodiphenyl Sulphone)

A new copolymer with nanostructure was chemically synthesized using an oxidizing agent between phenyl hydrazine hydrochloride (PH.HCl) and biologically active 4,4'-diaminodiphenyl sulfone (DADPS). The copolymer showed considerable solubility in common organic solvents such as chloroform, dimethyl formamide (DMF), dimethyl sulphoxide (DMSO) and tetrahydrofuran (THF). The copolymer showed electrical conductivity of 2.14x10 -2 S cm -1 . The copolymer formation between these two monomers was confirmed by Fourier Transformation IR, 1 H NMR spectral studies, X-ray diffraction studies and scanning electron microscopic (SEM) data. The UV-Visible spectrum also showed the presence of benzene and NH units in the copolymer.

Thermal behaviour of bis-benzoxazines derived from renewable feed stock 'vanillin'

Several bis-benzoxazine monomers (Va-BBz)s were synthesized using a naturally occurring phenol: vanillin, different diamines such as ethylene diamine (EDA), diaminodiphenyl sulphone (DDS), diaminodiphenyl ether (DDE), diaminodiphenyl methane (DDM) and 2,2′-bis [4-(4-aminophenoxy)phenyl] propane (BAPP) and paraformaldehyde. The structure of the bis-benzoxazine monomers was characterized by FT-IR, 1H and 13C NMR. The effect of structure on curing behaviour and thermal properties was evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The poly(bis-benzoxazine)s derived from vanillin had high Tg (202–255 °C), high char yield (52–76%) and excellent thermal stability due to highly cross-linked nature of the polymer. Adhesive strength of cured resins (i.e. poly(Va-BBz)s) were also evaluated at 200 °C.