Isophorone Diamine Research Articles

Enhancement of Nanoclay Dispersion and Exfoliation in Epoxy Using Aminic Hardener Treated Clay

Exfoliation and dispersion of nanoclays in epoxy matrices plays an important role in achieving better physical and mechanical properties of resultant nanocomposites. In this article, modification of clay with an aminic hardener for the increment of dispersion and exfoliation into the epoxy matrix has been investigated. In the solvent media, a slurry of hydrophilic Na-Montmorrilonite was mixed and treated with isophoronediamine (IPDA). The nanocomposites containing epoxy and IPDA-modified clay were produced through a recently developed “slurry compounding” method. Dispersion and exfoliation of the modified clay and the microstructure of the resultant nanocomposite were studied by optical microscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. The samples were then compared with the high shear mixed and sonicated nanocomposites containing commonly used quaternary ammonium modified clays. The comparison showed that dispersion and exfoliation of hardener-modified organoclays in epoxy have been improved due to the treatment of clay and the compounding method.

An Open-framework Strontium Phosphate Containing a Novel 412 Cages

A novel strontium phosphite open-framework H2[Sr6(HPO3)7] (denoted as ZZ-2, ZZ = Zhen Zhu) was hydrothermally synthesized by using isophorondiamine (IPDA) as the trial structure-directing agent. Single crystal structure refinement discloses that ZZ-2 crystallizes in the trigonal space group R-3 with the cell parameters of a = 16.410(2) Å, b =16.410(2) Å, c = 6.8651(14) Å, ? = 114.61(5)°, ? = 90°, V = 1601.0(5) Å3, Z = 3. The structure of ZZ-2 is constructed by eight coordinated SrO8 and HPO3 pseudo pyramids. A novel 412 cages existed in the structure with a proton located in the center of the cage. the P-H bonds stretch in all cages, hydrogen proton at the center of the cage to balance framework.

Abrasion and nanoscratch in nanostructured epoxy coatings

AbstractA series of epoxy nanostructured coatings based on diglycidyl ether of bisphenol A (DGEBA) and an isophorone diamine crosslinker was prepared. Top‐down nanocomposites (3% nanofiller) were obtained by the mechanical dispersion of nanoalumina, silanized nanoalumina, and organomodified clays. Bottom‐up hybrids were instead achieved after the silanization of the DGEBA resin and after cocrosslinking with tetraethylorthosilicate through a self‐catalyzed sol–gel process. The curing process of the nanocomposites was studied by differential scanning calorimetry and suggested an overall increase in the crosslinking kinetics in the presence of nanoparticles. Other characterization included dynamic mechanical analysis, Buchholtz indentation hardness testing, and Taber abrasion testing. Finally, atomic force microscopy (AFM) techniques were used to study the surface morphology of the coatings and to produce nanoscratches. We concluded that, in the top‐down nanocomposites, there were minor changes in the surface hardness and a slight improvement in the abrasion resistance, whereas the nanoscratch resistance assessed by AFM tests showed significantly better performances in the hybrid coatings obtained through sol–gel chemistry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Preparation and Characterization of Waterborne Hyperbranched Polyurethane-Urea and Their Hybrid Coatings

A series of novel waterborne hyperbranched polyurethane-urea (WHBPU) were prepared with different chain extenders (diamine, diol, and siloxane) by a systematic reaction process. Initially, the hyperbranched polyester polyol was prepared by reacting polytetramethyleneglycol (PTMG)-1000 with 2,2-bis(hydroxymethyl) propionic acid (DMPA) in a molar ratio of 1:14 (3rd generation) at 160 °C by one pot synthesis. This was reacted with an adduct of isophorone diisocyanate (IPDI) and DMPA with NCO:OH mole ratio of 1.6:1. Then 50% of free NCO in these prepolymers was reacted with three different chain extenders (diol, diamine and APTES). This reaction mixture was neutralized with triethyl amine and another 50% of free NCO was chain extended with isophorone diamine during water dispersion. The obtained polyester was characterized with Fourier transform-infrared spectroscopy (FT-IR), 1H and 13C NMR, respectively. The properties of WHBPU and their hybrid coatings were studied by FT-IR, 1H NMR, thermogravimetric analyz...

Liquid chromatography method to determine polyamines in thermosetting polymers

A simple, robust and sensitive analytical method to determine three polyamines commonly used as hardeners in epoxy resin systems and in the manufacture of polyurethane is reported. The studied polyamines are: one tetramine, TETA (triethylenetetramine), and two diamines, IPDA (Isophorone diamine) and TCD-diamine (4,7-methano-1H-indene-5,?-dimethanamine, octahydro-). The latter has an incompletely defined structure, and, as far as we know, has not been previously determined by other methods. All three polyamines contain primary amines; TETA also contains secondary amines. The analytical method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, used for the first time for these compounds, followed by high performance liquid chromatography (HPLC) analysis with a fluorescence (FL) detector ( λ excitation 248 nm, λ emision 395 nm). The HPLC-DAD-LTQ Orbitrap MS was used in order to provide structural information about the obtained derivatized compounds. The hybrid linear ion trap LTQ Orbitrap mass spectrometer has been introduced in recent years and provides a high mass accuracy. The structures of the derivatized analytes were identified from the protonated molecular ions [M+H] + and corresponded to the fully labelled analytes. The following analytical parameters were determined for the method using the HPLC-FL: linearity, precision (2.5–10%), instrumental precision intraday (0.8–1.5%) and interday (2.9–6.3%), and detection limits (0.02–0.14 mg L −1). The stability of stock solutions and derivatized compounds was also investigated. The method was applied to determine the amine free content in epoxy resin dust collected in workplaces.

Adsorption Efficiency of Respirator Filter Cartridges for Isocyanates

In some industries, the temperature and the humidity will vary greatly between different work places, such as outdoor work in arctic or tropical climates. There is therefore a need to test respirator filters at conditions that simulate conditions that are relevant for the industries that they are used in. Filter cartridges were exposed to controlled atmospheres of varying isocyanate concentration, air humidity, and temperature in an exposure chamber. For isocyanic acid (ICA) and methyl isocyanate (MIC), the exposure concentrations were between 100 and 200 p.p.b., monitored using a proton transfer reaction mass spectrometer. ICA and MIC were generated by continuous thermal degradation of urea and dimethylurea. The breakthrough was studied by collecting air samples at the outlet of the filter cartridges using impinger flasks or dry samplers with di-n-butylamine as derivatization reagent for isocyanates followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. For hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), the exposure concentrations were between 4 and 20 p.p.b. and were generated by wet membrane permeation. To reveal the profile of adsorption in different layers of the respirator filters, representative samples from each of the layers were hydrolyzed. The hydrolysis products hexamethylene diamine and isophorone diamine were determined after derivatization with pentafluoropropionic anhydride (PFPA) followed by LC-MS/MS analysis. The two filter types studied efficiently absorbed both ICA and MIC. There was no trend of impaired performance throughout 48-h exposure tests. Even when the filters were exposed to high concentrations (approximately 200 p.p.b.) of ICA and MIC for 96 h, the isocyanates were efficiently absorbed with only a limited breakthrough. The majority of the HDI and IPDI (>90%) were absorbed in the top layers of the absorbant, but HDI and IPDI penetrated farther down into the respirator filters during 120 h of exposure as compared to 16 h exposure.

Synthesis and Characterization of a Layered Uranium Phosphites

A novel layered oxouranium phosphite open-structure [C10H24N2]?[(UO2)2(HPO3)3]?H2O (denoted as ZZ-1) was hydrothermally synthesized by using isophorondiamine (IPDA) as the template. Single crystal structure refinement discloses that ZZ-1 crystallizes in the monoclinic space group P21c with the cell parameters of a = 18.347(4)A, b = 6.7341(13)A, c = 20.639(4)A, β = 114.61(3)°, V = 2318.2(8) A3 , Z = 2. The structure of ZZ-1 is constructed by UO7 monomer, U2O12 dimer and HPO3 groups. The monomeric UO7 or dimeric U2O12 is connected by HPO3 groups to form two types of 4-ring chains. An undulating sheet is then generated by connecting these two types of chains via HPO3 bridges. The layer structure is formed by stacking the sheet along the direction with the organoamine cations and water molecules intercalated in the interlayer spaces with strong H-bonds to the framework oxygen atoms. Although a mixture of cis and trans IPDA is used, only cis PDA serves as the template. A typical green light emission of UO22+ is observed when excited by 266 nm laser.

Comparative Study of the Effect of Addition of Silica and Silicate Nanofillers on the Properties of Epoxy Coatings

The effect of adding different amounts (0.5–3 wt%) of nanosilica (NS) and organomodified montmorillonite (MMT) to diglycidyl ether bisphenol A (DGEBA) cured with isophorone diamine at different temperature on the viscoelastic, topographical and gelation properties of epoxy resin was studied. Gel time measurements revealed that both NS and MMT accelerated the curing reaction of DGEBA with IPDA. Both nanofillers were adequately dispersed in DGEBA. The particle size distribution depended on the amount of nanofiller. A broader distribution for NS than for MMT filled epoxy was obtained. On the other hand, an increase in the curing temperature was required to obtain the intercalation of the epoxy into the MMT tactoids. At room temperature, the addition of NS increased both the stiffness (high storage modulus) and the toughness (an increase in the area and height of the tan δ curve) of epoxy, but no significant differences were found by curing at higher temperature. Epoxy/MMT composites showed higher storage modulus in the rubbery region. The improved properties imparted by NS can be ascribed to the interactions between the silanol moieties on the nanosilica surface and the polar groups in the epoxy, whereas the improvement imparted by MMT organoclay was related to tactoid intercalation within the epoxy matrix.

Influence of the filler CaCO3 on the cure kinetic of the epoxy network diglycidyl ether of bisphenol a (BADGE n = 0) with isophorone diamine

AbstractThe influence of the presence of CaCO3 on the cure reaction of the epoxy network diglycidyl ether of bisphenol A with isophorone diamine has been studied. The total enthalpy of reaction, the glass transition temperature and the partial enthalpies at different isothermal temperatures have been determined using differential scanning calorimetry (DSC) in dynamic and isothermal mode. A kinetic model accounting the influence of the diffusion of the reactive groups at high conversions was used. All the kinetic parameters have been compared with those of the system without filler (CaCO3). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

X-ray Micro Computed Tomography investigation of accelerated thermal degradation of epoxy resin/glass microsphere syntactic foam

The heat resistance and the structural integrity of syntactic foam materials are vital for their high performance. Syntactic foam made of hollow glass microspheres and Diglycidyl Ether of Bisphenol A (DGEBA) based epoxy resin cured with Isophorone Diamine (IPD) hardener was subjected to oxidative thermal stress cycles. The degraded syntactic foam sample was examined using an X-ray Micro Computed Tomography (XμCT) to evaluate its internal damage between each state in a combined effect of cycling and increased temperature. Glass microsphere fracture, void enlargement and resin microcracks were observed as a result of the thermal stress using 3D XμCT images. The reconstructed slice representation showed the microcracks and microsphere damage distribution inside the sample. The damaged glass spheres percentage is shown to increase sharply with the progress of the thermal cycle. There was no change in the local density of the syntactic foam as a result of the thermal cycle. An XμCT system proves to be a successful non-destructive technique for examining syntactic foam for defects and structural damages in the micron scale.

Time‐of‐flight secondary ion mass spectrometry investigation of epoxy resin curing behavior in real time

AbstractTime‐of‐flight secondary ion mass spectrometry and principal components analysis were used in real time to monitor the progress of curing reactions on the surface of a diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol F (DGEBF) epoxy resin blend reacted with the diamine hardener isophorone diamine at different time intervals. Molecular ions in the mass spectra that characterized the curing reactions steps, including blocking, coupling, branching, and crosslinking, were identified. The aliphatic hydrocarbon ions were correlated to the curing reaction rate, and this indicated that coupling and branching occurred much faster than the blocking and crosslinking curing reactions steps. The total conversion of the coupling and branching reaction steps were followed on the basis of changes with time in the relative ion intensity of molecular ions assigned to the DGEBA/DGEBF, aliphatic hydrocarbon, epoxide, and aromatic ring structures. Indicative measures of crosslinking density were monitored through the observation of changes in the ratio of the relative intensities of the aliphatic hydrocarbon and hydroxyl molecular ions over time. The curing reaction conversion was established by the observation of the changes in the relative ion intensity of the molecular ions that were related to the DGEBA/DGEBF molecules. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Novas tendências dos polímeros epoxídicos: propriedades biológicas in vitro de formulações para aplicações médicas

Este trabalho descreve as propriedades biológicas in vitro de três formulações epoxídicas usando o monômero do tipo éter diglicidílico do bisphenol-A (DGEBA) com três co-monômeros do tipo poliamina alifática de maneira independente; trietilenotetramina (TETA), 1-(2-aminoetil)piperazina (AEP) e isoforonodiamina (IPD). As interações biológicas entre os polímeros obtidos e o sangue foram estudadas in vitro utilizando quatro métodos biológicos diferentes. Estudos de adsorção protéica, adesão plaquetária, formação de trombos e citotoxicidade são apresentados e discutidos. Os ensaios de adsorção protéica mostraram que a superfície dos polímeros adsorve mais albumina humana do que fibrinogênio humano. Os resultados de adesão plaquetária e formação de trombos indicaram que os sistemas DGEBA-IPD e DGEBA-AEP exibem boa hemocompatibilidade. Os três polímeros epoxídicos não revelaram toxicidade com células de ovário de hamster chinês. Os resultados obtidos indicam que os polímeros epoxídicos baseados no IPD obedecem aos critérios de hemocompatibilidade e citotoxicidade exigidos de um biomaterial. Os polímeros epoxídicos baseados nas aminas AEP e TETA exibem apenas um comportamento não citotóxico.

Material compósito epóxi-amina para restauração dentária

O objetivo deste trabalho foi desenvolver materiais compósitos à base de resina epoxídica para restauração dentária, para uso em próteses fixas. Diferentes compósitos foram formulados utilizando a resina líquida do tipo éter diglicidílico do bisfenol-A (DGEBA), com três diferentes agentes de cura tais como trietilenotetramina (TETA), isoforonodiamina (IPD) e 1-(2-aminoetil)piperazina (AEP), como sistemas independentes, contendo diferentes concentrações de micro-partículas de quartzo. As formulações foram otimizadas usando métodos de titulação de grupos funcionais, bem como a incorporação de diferentes quantidades de quartzo. As formulações foram avaliadas por ensaios mecânicos de compressão uniaxial e por ensaios biológicos in vitro usando células de ovário de hamster chinês. O sistema com AEP manifestou a maior deformação nos ensaios de compressão. O modulo de elasticidade e a tensão limite de escoamento aumenta com a quantidade de quartzo. Entretanto, a resistência à ruptura diminui significativamente com o aumento da concentração de material inorgânico. Os compósitos com TETA e AEP apresentam os melhores comportamentos mecânicos. As interações biológicas dos polímeros epoxídicos revelaram que não existem sinais de citotoxicidade. Os materiais compósitos desenvolvidos podem ser utilizados como biomateriais com boas propriedades mecânicas e biológicas, especificamente na fabricação de próteses ortodônticas, sendo ainda de fácil fabricação e baixo custo quando comparados com os materiais já utilizados para estes fins.

Heterogeneous Ziegler-Natta Catalysts

The facile chemical fixation of 18 wt.% carbon dioxide by catalytic carbonation of sorbitol glycidyl ether, monitored by means of NMR and FTIR spectroscopy, affords sorbitol-based cyclic ether carbonate (SEC) as versatile intermediate for producing renewable non-isocyanate polyhydroxydroxyurethane (NIPU) materials. In sharp contrast to the solid, crystalline and highly insoluble pure sorbitol tricarbonate (STC), melting above 200 °C close to its decomposition temperature, SEC is liquid at room temperature and fully miscible with a wide variety of polyfunctional amine curing agents. Despite high SEC carbonate functionality (4.2 mol/kg), both gel time and pot-life time measurements confirm easy processing by curing SEC with polyfunctional aliphatic amines to produce new families of sorbitol-based NIPU materials. Particularly, blends combining flexible long-chain diamines such as dimer fatty acid based diamine (Priamine™ 1074) or polyether triamine (Jeffamine™ T403), respectively, with rigid short-chain diamines such as 1,6-hexamethylene diamine (HMDA), 1,12-dodecyl diamine (DDA), 2,2,4-trimethylhexamethylene diamine (TMHMDA) and isophorone diamine (IPDA), enable the simultaneous incorporation of soft and hard segments into NIPU networks. Moreover, miscible blends of SEC with STC remain liquid up to high STC content. Unparalleled by conventional bio-based NIPU chemistry, the curing of SEC or miscible SEC/STC blends, respectively, with IPDA yields sorbitol-based NIPU thermosets exhibiting significantly improved thermal and mechanical properties, as reflected by high glass transition temperatures surpassing 180 °C and Young moduli exceeding 4000 MPa.

ToF‐SIMS investigation of epoxy resin curing reaction at different resin to hardener ratios

AbstractTime‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and principal components analysis (PCA) were used to analyze diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol F (DGEBF) epoxy resin blend cured with isophorone diamine (IPD) hardener at different resin to hardener ratios. The aim was to establish correlations between the hardener concentration and the nature and progress of the crosslinking reaction. Insights into the cured resin structure revealed using ToF‐SIMS are discussed. Three sets of significant secondary ions have been identified by PCA. Secondary ions such as C14H7O+, CHO+, CH3O+, and C21H24O4+ showed variance related to the completion of the curing reaction. Relative intensities of CxHyNz+ ions in the cured resin samples are indicative of the un‐reacted and partially reacted hardener molecules, and are found to be proportional to the resin to hardener mixing ratio. The relative ion intensities of the aliphatic hydrocarbon ions are shown to relate to the cured resin crosslinking density. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Curing kinetics of the epoxy system diglycidyl ether of bisphenol A/isophoronediamine by Fourier transform infrared spectroscopy

AbstractThe curing reaction of an epoxy system consisting of a diglycidyl ether of bisphenol A (BADGE, n = 0) and isophoronediamine (IPD), was studied by Fourier transform infrared spectroscopy (FTIR). The degree of conversions and the reaction rates at different isothermal curing temperatures were calculated from the infrared spectra using a method derived from Beer's law. This method is based on the ratio of the height of the characteristic absorbance peak to reference absorbance peak. A kinetic model proposed by Sourour and Kamal has been used to fit experimental data. Copyright © 2008 John Wiley & Sons, Ltd.

Interaction of amines with native aluminium oxide layers in non-aqueous environment: Application to the understanding of the formation of epoxy-amine/metal interphases

Interaction of propylamine (PA), 1,2-diaminoethane (DAE) or 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine, IPDA) with native aluminium oxide layers in non-aqueous environment has been studied using time-resolved inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS). The formation of several surface complexes has been evidenced. Monodentate and bidentate metal-bond surface complexes (MBSC) result from interactions between the amine terminations of the molecule and aluminium cations by donation of the N lone electron pair to the metal ion (Lewis-like mechanism leading to O Al⋯N bonds). Monodentate and bidentate hydrogen-bond surface complexes (HBSC) are due to interaction of the amino group with surface hydroxyl groups by protonation of the amine termination (Brønsted-like mechanism leading to the formation of Al OH⋯N bonds) or interaction with carbonaceous contamination (C x O y H z ⋯N bonds). Diamines can also form mixed complexes with one amino group forming an O–Al⋯N bond and the other group forming an Al OH…N or C x O y H z ⋯N bond. Al OH⋯N and C x O y H z …N bonds are less stable under vacuum than O Al⋯N bonds, leading to partial desorption of the DAE molecules in vacuum and modification of the interaction modes. Only DAE and IPDA can lead to partial dissolution of the aluminium native (hydr)oxide films. A detailed mechanism of dissolution has been proposed based on the formation of mononuclear bidentate (chelate) MBSC by ligand exchange between the terminal η 1-OH and bridged μ 2-OH surface sites and the amino terminations of the molecule. The detachment of this complex from the surface is likely to be the precursor step to the formation of the interphase in epoxy-amine/metal systems.

Evaluación de la adherencia de uniones adhesivas metálicas con adhesivos epoxídicos modificados

En este trabajo fueron evaluadas las propiedades adhesivas de la resina epoxídica del tipo éter diglicidílico del bisfenol A. La resina fue modificada con dos modificadores poliméricos, uno de ellos un copolímero derivado del butadieno, y el otro un copolímero acrílico con el propósito de aumentar la tenacidad de la resina. Tres aminas alifáticas primarias fueron utilizadas como agentes de curado, trietilentetramina, N-(2-aminoetil)piperazina e isoforondiamina. Las propiedades adhesivas fueron investigadas usando la resina pura, así como la resina modificada. Las propiedades adhesivas de la resina modificada y pura fueron estudiadas usando como adherente una aleación de acero (ASTM A36). La adherencia fue evaluada por ensayos de adhesión usando tres geometrías de uniones adhesivas de acero-acero. El comportamiento reológico de los adhesivos fue investigado en condiciones isotérmicas. Los parámetros reológicos relacionados con la reacción de polimerización tales como velocidad de reacción, tiempo de manipulación, y tiempo de gelación de los adhesivos puros fueron relacionados con la estructura química del agente de curado. El tiempo de separación de fases, y de gelación de los adhesivos modificados fue relacionado con la morfología generada, y con la velocidad de la reacción, respectivamente. La morfología fue caracterizada por microscopia electrónica de barrido. La adherencia de las uniones adhesivas sometidas a las diferentes solicitaciones mecánicas fue relacionada a la morfología generada por la fase dispersa de cada modificador, y con las estructuras de redes de los adhesivos.

Cure kinetics of a diglycidyl ether of bisphenol a epoxy network (n = 0) with isophorone diamine

AbstractThe study of the cure reaction of a diglycidyl ether of bisphenol A epoxy network with isophorone diamine is interesting for evaluating the industrial behavior of this material. The total enthalpy of reaction, the glass‐transition temperature, and the partial enthalpies at different curing temperatures have been determined with differential scanning calorimetry in dynamic and isothermal modes. With these experimental data, the degree of conversion and the reaction rate have been obtained. A kinetic model introduces the mechanisms occurring during an epoxy chemical cure reaction. A modification of the kinetic model accounting for the influence of the diffusion of the reactive groups at high conversions is used. A thermodynamic study has allowed the calculation of the enthalpy, entropy, and Gibbs free energy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Mechanical properties of epoxy networks based on DGEBA and aliphatic amines

AbstractThe mechanical properties of epoxy networks based on diglycidyl ether of bisphenol A epoxy resin cured with various linear aliphatic amines, such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and cyclic amines such as 1‐(2‐aminoethyl)piperazine and isophorone diamine, were studied. General characteristics such as Tg, density, and packing density, were determined and related to the structure and funcionality of the curing agent. Dynamic mechanical spectra were used to study both the α and β relaxations. Tensile and the flexural tests were used to determine the Young's and flexural modulus, and fracture strength all in the glassy state. Furthermore, linear elastic fracture mechanics was used to determine KIC. As a rule, isophorone diamine network presented the higher tensile and flexure modulus while 1‐(2‐aminoethyl)piperazine gave the highest toughness properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007