Synthesis of a Sustainable and Bisphenol A-Free Epoxy Resin Based on Sorbic Acid and Characterization of the Cured Thermoset

In the present study, an epoxy compound, 1,2-epoxy-6-methyl-triglycidyl-3,4,5-cyclohexanetricarboxylate (EGCHC) synthesized from sorbic acid, maleic anhydride, and allyl alcohol is proposed. Using commodity chemicals, a bio-based carbon content of 68.4 % for the EGCHC resin is achieved. When cured with amine hardeners, the high oxirane content of EGCHC forms stiff cross-linked networks with strong mechanical and thermal properties. The characterization of the epoxy specimens showed that EGCHC can compete with conventional epoxy resins such as DGEBA. A maximum stiffness of 3965 MPa, tensile strength of 76 MPa, and T_g of 130 °C can be obtained by curing EGCHC with isophorone diamine (IPD). The cured resin showed to be decomposable under mild conditions due to the ester bonds. The solid material properties of EGCHC expose its potential as a promising bisphenol A, and epichlorohydrine free alternative to conventional petroleum-based epoxies with an overall high bio-based carbon content.     

Cross-linking of poly(methyl methacrylate) by aminolysis of ester functions with diamines

The cross-linking of poly(methyl methacrylate) (PMMA) macromolecules by primary aliphatic diamines was carried out at 413–473 K, above the polymer glass transition temperature. The spherical grains of the suspension-prepared polymer (0.25–0.8 mm) and the molar ratio to amine above 20 were used. The reaction is characterized by an induction period before the macroscopic gel was observed and by fast network formation. Both phenomena are temperature-dependent (87± 2 kJ mol^?1). The rate of gelation is dependent also on the type of diamine; the shorter induction period of gelation and the higher rate of cross-linking were observed when amino groups were separated with longer alkyl chains. From the kinetics of amine uptake with PMMA, however, it can be concluded that gel formation is influenced also by the reactivity of amine in the transamination reaction and by the amount of bounded diamine. Aminolysis of PMMA ester groups proceeds from the very beginning of heating of the reaction charge. The polymer cross-linking prevails when there is more than 60% of diamine attached to PMMA in dependence on the amine type used. © 1995 John Wiley & Sons, Inc.     

Polyurethanes from soybean oil,aromatic, and cycloaliphatic diamines by nonisocyanate route

Polyurethanes were prepared via a nonisocyanate route, by reacting carbonated soybean oil (CSBO) with aromatic and cycloaliphatic diamines. Nonisocyanate polyurethanes prepared form CSBO and aliphatic diamines have relatively low tensile strength and one of the possible ways to increase strength and rigidity is to use diamines with rigid aromatic or cyclic structure. The effect of amine structure and amine to carbonate ratio on polyurethane structure and mechanical, physical, and swelling properties was studied. m‐xylylene diamine (m‐XDA), p‐xylylene diamine (p‐XDA), and isophorone diamine were used as the reactants, with amine to carbonate ratios of 0.5 : 1, 1 : 1, and 1 : 2. All amines produced elastomeric polyurethanes with glass transitions between ?6° C and 26°C, as measured by differential scanning calorimeter (DSC). T_g was primarily controlled by the amine‐to‐cyclic carbonate ratio, and to a lesser extent by the amine structure. The highest tensile strength was obtained for p‐XDA and the lowest for m‐XDA as a result of differences in hydrogen bonding. Tensile strength and hardness were higher than in aliphatic diamine‐based polyurethanes. Swelling in toluene and water depended on the polarity of polyurethane networks that was dominantly controlled by the amine‐to‐cyclic carbonate ratio. Swelling in toluene was higher at the lower amine to carbonate ratio due to lower polarity of the polyurethane matrix. Swelling in water behaved quite the opposite, the degree of swelling for the more polar polyurethane matrix was higher. Reaction temperatures of 70–100°C were high enough to promote ester group cleavage and along with urethanes, amide formation was always present. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Zeta potential, contact angle and the use of amines in the chemical dewatering of froth-floated coal

The paper describes the historical development of coal preparation within the United Kingdom, highlighting the problems and economic implications associated with the dewatering of froth-floated coals. Theoretical considerations of the filtration process suggested that an increase in the receding contact angle would have beneficial effects on the residual moisture content and from a knowledge of the ionic characteristics, cationic reagents of the amine group were selected.

Buchner funnel tests allowed the preliminary screening of some ten amine compounds; a diamine was shown to offer the most potential. This was examined in more detail to determine its effect on the zeta potential and contact angel of coal slurries, indications being that maximum dewatering (hydrophobicity) should be achieved at maximum contact angle and at the zero point of charge of the system. Pilot-scale filtration tests with the diamine confirmed the earlier Buchner funnel results and a reduction of approximately ten percentage points at a diamine dosage of 0.4 kg/tonne was indicated.     

Cationic polyelectrolytes,XI. Polymers with quaternary N-atoms in the main chain obtained by condensation polymerization of epichlorohydrin with amines

Water soluble cationic polyelectrolytes containing quaternary nitrogen atoms within the main chain were prepared via condensation polymerization of epichlorohydrin (ECH) with dimethylamine (DMA) and N,N-dialkylaminoalkylamines. The main parameters of the reaction that influence the polymer properties are: DMA/asymmetrical diamine molar ratio, the initial concentration of amine solution, NaOH/amine molar ratio, ECH/amine molar ratio, and asymmetrical diamine structure. The feature of flexible polyelectrolyte own to the investigated polymers was emphasized by the viscosimetric behaviour in dilute aqueous solutions with and without salt presence.     

Polyimides from diisocyanates,dianhydrides, and tetracarboxylic acids

High molecular weight polyimide resins have been prepared by the reaction of diisocyanates and a mixture of dianhydrides and their acids in the presence of a tertiary amine catalyst. The polyimides thus formed can be made into tough flexible films similar to those polyimides prepared by the conventional method of reacting a dianhydride with a diamine. The preparation of high molecular weight polymer is affected by the purity of reagents, the anhydride-acid ratio, temperature, and moisture. Evidence from model compound studies is presented regarding the nature of the reaction mechanism.     

Polypropylene nanocomposite using maleated PP and diamine

The insertion of the aliphatic diamine inside the organoclay will help the dispersion of the clay platelets in the PP/clay nanocomposite due to the reaction between the maleated PP and the diamine. Cloisite®20A was just simply mixed with hexamethylene diamine (HMDA) under shearing condition in Brabender mixer. HMDA group was successfully penetrated into silicate layers. As a result of penetration, d‐spacing of organoclay was increased. Polypropylene/clay nanocomposites were prepared by compounding with maleated PP and amine‐treated clay. From the FTIR spectra, reaction between amine group and maleic‐anhydride group was confirmed. The effect of the organoclay on the properties of the nanocomposite such as the morphology, dynamic mechanical properties, crystal structure and crystallization behavior, glass transition temperature, thermal stability, and tensile properties were investigated and analyzed. Nanocomposites with amine‐treated clays show enhanced properties compared with those with non–amine‐treated clay (Cloisite®20A). From the TEM analysis, nanocomposites with amine‐treated clays shows better dispersibility compared with those with Cloisite®20A alone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

含酰胺基双子表面活性剂的合成与性能

通过采用酰胺中间体和溴代烷烃反应,合成出一类新型的含酰胺基双子季铵盐阳离子表面活性剂——二溴双（N-十二（或十四、十六）烷基二甲基叔胺基）乙二酰胺,用IR、^1H—NMR表征了其结构,并对其表面性能进行测试,证实所合成的双子表面活性剂结构正确,其表面性能均优于同碳单疏水链表面活性剂。     

Relaxations in thermosets. XXIX. Calorimetric studies of the curing kinetics of nonstoichiometric diamine–epoxy mixtures

The curing kinetics of nonstoichiometric mixtures of diglycidyl ether of bisphenol A, with ethylene diamine, propylene diamine, and hexamethylene diamine have been measured under both isothermal and ramp-curing condition. Their kinetics are faster than for stoichiometric compositions and the reactions reach completion. The total heat evolved for the amine-rich composition is greater than for the amine-deficient. None of the available formalisms is consistent with the results. This and the variation in the heat of reaction indicate that steric effects are important for both the reaction rate and the heat evolved. It is argued that the standard heat of reaction of primary amine with the epoxide group differs from that of secondary amine. © 1994 John Wiley & Sons, Inc.     

Thermoplastic‐modified epoxy resins cured with different functionalities amine mixtures: Morphology,thermal behavior,and mechanical properties

Epoxy matrices inherent brittleness and poor crack resistance make necessary some form of toughening. In this work, to improve their fracture toughness and ductility epoxy matrices were modified by changing its architecture and by the addition of a third component. The matrices architecture were modified by stoichiometrically reacting a bifunctional epoxy resin with different functionalities amine mixtures, one of which being a monoamine that plays the role of chain extender. In the modification by the addition of a third component, poly(methyl methacrylate) (PMMA) was selected as modifier. PMMA is initially miscible with epoxy/amine systems but can phase separate during curing. The kinetics and miscibility of these systems were studied previously. At constant curing conditions, materials from completely opaque (phase separated) to transparent (miscible) can be obtained with the increase in monoamine content. In this work, the effects of the modifier content and of the monoamine : diamine ratio in stoichiometric epoxy/amine mixtures on the resultant morphologies as well as on their thermal and mechanical properties was studied.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Surface functionalization of SBA-15 particles for ibuprofen delivery

We have synthesized SBA-15 particles and functionalized their surface with different functional groups (amine, diamine, and sulfonic acid groups) to use them as carrier materials in drug delivery. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption, and zeta potential measurements were used to characterize the synthesized particles. After surface functionalization, the surface of the sulfonic acid-functionalized particles was more acidic than that of the other particles. Using ibuprofen as a model drug, we found that the release rate increased at higher pH. Furthermore, the particles with the sulfonic acid groups exhibited higher release rate than those with the amine and diamine groups. We explained the difference in the release rate using different electrostatic interaction between drug and particle surface that was caused by the surface functionalization. These results should enable design of drug carrier materials based on the SBA-15 particles with the desired release rate.     

An empirically derived model for further increasing microwave curing rates of epoxy-amine polymerizations

The reaction rates of common epoxy resins with diamine crosslinking agents in uniform microwave fields have been compared according to a variety of structural features. A statistically designed experimental matrix was used to determine that the curing rates were linearly dependent on only two significant variables, amine basicity, and degrees of rotational freedom (entropy) of the reactants. Surprisingly, the molecular polarizability, which is commonly understood to be responsible for the transfer of microwave electromagnetic energy to molecules with permanent dipoles, had no significant effect even as a dependent variable. A very high probability model was produced that accurately predicts the reactivities of epoxide and diamine reactants with respect to specific structural features. Further evidence is provided for a dominant linear pregelation polymerization and a uniform microwave reaction field.     

Curing kinetics and mechanical properties of fast curing epoxy resins with isophorone diamine and N-(3-aminopropyl)-imidazole

Fast curing epoxy resins were prepared by the reactions of diglycidyl ether of bisphenol A with isophorone diamine (IPD) and N-(3-aminopropyl)-imidazole (API), and their curing kinetics and mechanical properties influenced by IPD content were also investigated. The analysis of curing kinetics was based on the nonisothermal differential scanning calorimetry (DSC) data with the typical Kissinger, Ozawa, and Flynn–Wall–Ozawa models, respectively. The glass-transition temperature was also measured by the same technique. Additionally, the mechanical properties including flexural, impact, and tensile performances were tested, and the curing time was estimated by isothermal DSC. The degree of cure (α) dependency of activation energy (E_a ) revealed the complexity of curing reaction. Detailed analysis of the curing kinetics at the molecular level indicated that the dependence of E_a on the α was a combined effect of addition reaction, autocatalytic reaction, viscosity, and steric hindrance. From the nonisothermal curves, the curing reaction mechanism could be proposed according to the increasingly obvious low temperature peaks generated by the addition reaction of epoxy group with the primary amines in API and IPD molecules. Using the preferred resin formulation, the resin system could be cured within 10 min at 120 °C with a relatively good mechanical performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47950.     

Reaction of aromatic amines with epoxidized natural rubber latex

Since oxidizability of raw rubber is adversely affected by epoxidation, an attempt was made to bind an amine antioxidant to the rubber molecule through the oxirane group. Effective binding was observed only if the latex is neutralized before addition of the amine. Of the three amines used, 4-amino-para-phenyl diamine (pAA) reacted faster than meta-nitro-aniline (mNA), where as N-isopropyl-N′-phenyl-para-phenyl diamine (IPPD) was the least reactive. Crosslinking was observed with the primary amine, while, with higher epoxy contents, cyclization products were also formed. mNA had little effect on oxidation resistance once it was bound.     

含酰氨基双子表面活性剂的合成与稳定性研究

以酰胺中间体和溴代烷烃反应,合成出一类新型的含酰胺基双子季铵盐阳离子表面活性剂——二溴双(N-十二(或十四、十六)烷基二甲基叔胺基)乙二酰胺,用IR、1H-NMR对其进行结构鉴定,测定其表面性能,并对其热稳定性和酸碱稳定性进行研究。结果表明,此类表面活性剂表面性能优良,具有较好的热稳定性,且在碱性溶液中易降解,具有较好的环保性能。     

Reaction kinetics of 2‐((2‐aminoethyl) amino) ethanol in aqueous and non‐aqueous solutions using the stopped‐flow technique

Observed pseudo‐first‐order rate constants (k_o) for the reaction between CO₂ and 2‐((2‐aminoethyl) amino) ethanol (AEEA) were measured using the stopped‐flow technique in an aqueous system at 298, 303, 308 and 313 K, and in non‐aqueous systems of methanol and ethanol at 293, 298, 303 and 308 K. Alkanolamine concentrations ranged from 9.93 to 80.29 mol m^?3 for the aqueous system, 29.99–88.3 mol m^?3 for methanol and 44.17–99.28 mol m^?3 for ethanol. Experimentally obtained rate constants were correlated with two mechanisms. For both the aqueous‐ and non‐aqueous‐AEEA systems, the zwitterion mechanism with a fast deprotonation step correlated the data well as assessed by the reported statistical analysis. As expected, the reaction rate of CO₂ in the aqueous‐AEEA system was found to be much faster than in methanol or ethanol. Compared to other promising amines and diamines studied using the stopped‐flow apparatus, the pseudo‐first‐order reaction rate constants were found to obey the following order: PZ (cyclic‐diamine) > EDA (diamine) > AEEA (diamine) > 3‐AP (primary amine) > MEA (primary amine) > EEA (primary amine) > MO (cyclic‐amine). The reaction rate constant of CO₂ in aqueous‐AEEA was double that in aqueous‐MEA, and the difference increased with an increase in concentration. All reaction orders were practically unity. With a higher capacity for carbon dioxide and a higher reaction rate, AEEA could have been a good substitute to MEA if not for its high thermal degradation. AEEA kinetic behaviour is still of interest as a degradation product of MEA. © 2012 Canadian Society for Chemical Engineering     

In-Situ Evaluation of the Diffusion of Epoxy and Amine in Thermoplastic Polymers

The current study investigates the diffusion of a bisphenol A type epoxy resin and a diamine curing agent into polysulfone (PSU) using a Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) technique. The diffusion of epoxy or amine through the film was monitored in real time by measuring the changing intensity of selected characteristic absorbance bands in each of the polymers. The diffusion coefficients for the epoxy and amine were determined independently using the appropriate solution to the diffusion equation and the experimental data. Diffusivities were evaluated at several temperatures, and an Arrhenius relationship was observed. Results show that the diffusivity of amine is an order of magnitude greater than the diffusivity of epoxy at each temperature tested. Furthermore, the epoxy diffusion appears to be Fickian, while the diffusion of amine appears to be non-Fickian.     

THE EXTRACTION OF COBALT(II) FROM A THIOCYANATE MEDIUM BY SOME DIAMINE AND MONOAMINE EXTRACTANTS DISSOLVED IN 5% ISODECANOL - BENZENE

The tertiary amine extractants N,N,N’,N’-tetra-n-octylethylenediamine, N,N-di-n-octyl-2-(aminomethyl)pyridine and Alamine 336 were used to extract cobalt(II) from a thiocyanate medium. The extraction equilibria were identified and the extraction constants for these equilibria are presented.

Thiocyanic and sulphuric acid extraction was investigated. The protonation constants of the tertiary amines with these acids are reported.

The potential of the chelate mode, displayed by tertiary diamine extractants, was evaluated. The extraction properties of tertiary diamine extractants were demonstrated to be superior to a tertiary monoamine extractant, Alamine 336.     

Kinetics study of carbon dioxide absorption in aqueous solutions of 1,6-hexamethyldiamine (HMDA) and 1,6-hexamethyldiamine, N,N′ di-methyl (HMDA, N,N′)

A study towards the kinetics of CO₂ in aqueous solutions of 1,6-hexamethyl diamine (HMDA) and 1,6-hexamethyl diamine, N,N′ di-methyl (HMDA, N,N′) was performed at concentrations ranging from 0.5 to 2.5 mol/L and temperatures from 283 up to 303 K. The kinetics data were determined by CO₂ absorption experiments using a stirred cell reactor with a flat interface between gas and liquid. These new CO₂ solvents were identified in earlier work for their high CO₂ capacity and limited corrosiveness. The experimental technique was validated using kinetic experiments for a 2.5 mol/L monoethanolamine solution. In view of double amine functionality and the six carbon chain between the amine groups, attention was paid to whether the amine groups acted independently and whether or not internal cyclisation would affect the carbamate forming mechanism. The reaction order with respect to HMDA was found to vary from 1.4 to 1.8 with increasing temperature. Absorption experiments in an equimolar solution of HMDA with HCl showed that the two amine groups react independently from each other towards CO₂. The reactivity of both diamines was more than five times larger than for monoethanolamine. The secondary diamine HMDA, N,N′ was found to be even more reactive towards CO₂. Additionally, the effect of CO₂ loading on the kinetics was studied for 0.5 mol/L aqueous solutions of HMDA and HMDA, N,N′ at 293 K. Both solvents are from absorption kinetics point of view good candidates for further evaluation as solvent (-component) for CO₂ capture.     

Separation Behavior of Composite Polyamide Membranes from Mixed Amines: Effects of Interfacial Reaction Condition and Chemical Post-Treatment

Abstract

Composite polyamide membranes are prepared using in-situ interfacial polymerization using mixed amine system comprising 1,4-phenylene diamine and pipperazine. Separation performance of the membranes are studied as a function of the concentration of amine and acid chloride, the concentration ratio of the amines, nature of the acid chloride, and the presence of surfactant and acid acceptor in the aqueous reagent. The effect of esterification and hydrazide reactions involving residual carboxylic acid groups in the polymeric membranes on the co-polymeric composite membrane performance is also studied. The membrane performance can be tailored easily by conversion of the residual reactive functional groups in post-treatment.