Kinetic Method by Using Calorimetry to Mechanism of Epoxy-amine Cure Reaction

Using calorimetric method to reaction kinetics in solventless system, the quantitative aspects of the epoxy ring opening in the reaction between phenyl glycidyl ether and aniline have been discussed. Using the Mangelsdorf method we have found that this reaction system gives fairly clean kinetics through whole process. The kinetic picture of this reaction system is akin to diepoxy-diamine cure mechanism. It was detected kinetically, apart from exothermic effect of the reaction of the epoxy ring opening, the existence another exothermic process at the last stages of the reaction. The latter also contributes to the total heat. The contribution of this thermal effect to the total heat is found to be dependent on the reactant ratio. The data for the reaction between phenyl glycidyl ether and aniline could not be fitted well if uncatalyzed mechanism was ignored. Thus, the reaction of epoxy ring opening by aniline occurs by two concurrent pathways: one is uncatalyzed and the other, the main, is autocatalyzed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Kinetics and mechanism of the epoxide-amine polyaddition

The mechanism and kinetics of the epoxide-amine polyaddition reaction have been studied by isothermal and scanning DSC measurements. The initial concentrations of the reactants (epoxides: bisphenol-A-diglycidyl ether (DGEBA) and phenyl glycidyl ether (PGE), amines: N,N′-dibenzylethylenediamine (DBED) and aniline) in our model systems have been strongly varied. The suggested kinetic model describes the reaction behavior of mixtures with any initial epoxide/amine ratios over the whole range of cure by a single parameter set. To find the optimum kinetic parameters, we have solved the set of differential equations numerically by the technique of multivariate non-linear regression (Mult-NLR). Excellent agreement was obtained between calculated and experimental curves.     

Kinetic Method by Using Calorimetry to Mechanism of Epoxy-Amine Cure Reaction

The thermokinetic behavior of the reaction between phenyl glycidyl ether and aniline closely resembles the analogous diepoxy diamine cure reaction in that the reactants are assembled before bond-breaking step occurs, and does not proceed through free reacting groups. The mechanism of the reaction between phenyl glycidyl ether and aniline in solventless system involves in addition to mechanism of the epoxy ring opening, structure changes accompanied by phase separation related to the self-aggregation. In an attempt to obtain further information about the reaction mechanism, the DSC heating runs of the reacted samples have been examined. These results suggest that the observed endothermic peaks are associated with additional ordering. The latter takes place only at lower temperature than reaction temperature. Since the rate constant k ₂ values for autocatalysed reaction follow of Arrhenius behavior, it is possible to calculate the activation energy, which is E=51 kJ mol^-1. Analysis of the kinetic experiments demonstrates that the heat of reaction that are detected in kinetic measurements provide correct information about the mechanism of the process. This revised version was published online in August 2006 with corrections to the Cover Date.     

An analysis of the substitution effects involved in diepoxide-diamine copolymerization reactions

The relative reactivity of the functional groups present in aromatic amine and diepoxide monomers has been investigated by gel permeation chromatography. The ratio of rate constants for the consumption of the secondary and primary amine hydrogens involved in the reaction between aniline and phenyl glycidyl ether has been calculated to equal approximately 0.5. In the case of the reaction between N-methy aniline and diglycidyl ether of bisphenol A (DGEBA) the rate constant ratio for the consumption of the first and second epoxide groups in the DGEBA molecule is also approximately 0.5. In contradiction to previously published data these results suggest that substitution effects are unimportant for aromatic amines as well as DGEBA. Furthermore, etherification side reactions, consuming epoxide groups at the expense of the amine–epoxide reaction, also appear to be insignificant.     

Displacement reactions of 2-chloro- and 2,9-dichloro-1,10-phenanthroline: synthesis of a sulfur-bridged bis-1,10-phenanthroline macrocycle and a 2,2′-amino-substituted-bis-1,10-phenanthroline

The synthesis and structural assignments of 9-chloro-1,1-phenanthroline-2(1H)-thione and 1,10-dihydro-1,10-phenanthroline-2,9-dithione have been accomplished. The sulfur-bridged bis-1,10-phenanthroline macrocycle was readily prepared by heating the thione or equimolar amounts of the dithione and 2,9-dichloro-1,10-phenanthroline in diphenyl ether. Displacements of 2-chloro- or 2,9-dichloro-1,10-phenanthroline with N,N-dimethylethylenediamine afforded the corresponding amine and diamino analogues. An amino-substituted-2,2′-bis-1,10-phenanthroline has been prepared.     

New liquid‐crystal alignment agents based on fluorinated polyimides with trifluoromethyl‐substituted benzene or diphenylether in the side chain

Fluorinated copolyimides derived from 4,4′‐oxydiphthalic anhydride (ODPA) with 4,4′‐oxydianline (ODA) and trifluoromethyl‐containing aromatic diamines have been synthesized and characterized. The trifluoromethyl‐containing diamines include 2,4‐diamino‐3′‐trifluoromethylazobenzene, 2,4‐diamino‐1‐[(4′‐trifluoromethylphenoxy) phenyl] aniline, 3,5‐diamino‐1‐[(4′‐trifluoromethylphenoxy) phenyl] benzamide, 3,5‐diamino‐1‐[(3′‐trifluoromethyl) phenyl] benzamide, 1,4‐bis(4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl) benzene, 3,5‐diaminobenzenetrifluoride, 4,4′‐diamino‐4″‐(p‐trifluoromethyl phenoxy) triphenylamine, and 4‐[(4′‐trifluoromethylphenoxy) phenyl]‐2,6‐bis(4″‐aminophenyl)pyridine. Strong and flexible copolyimide films, produced by casting the polyamic acid solution followed by thermal imidization, exhibited great thermal stability and high mechanical properties. The polyimides had an ultraviolet–visible absorption cutoff at 330–340 nm and pretilt angles as high as 20° for nematic liquid crystals, making them great potential candidates for advanced liquid‐crystal display applications. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1583–1593, 2002     

Application of novel polymers with S‐alkylsulfonium salt moieties as alkylating agents and thermal latent cationic initiators

Sulfonium‐containing polymers prepared from dibenzothiophene and diphenyl sulfide were applied as both alkylating agents and latent initiators for the cationic polymerization of glycidyl phenyl ether. The alkylation of acetonitrile proceeded smoothly with poly(S‐n‐octyl‐2‐vinyldibenzothiophenium tetrafluoroborate) ( 4 ; 64 mol % octyldibenzothiophenium tetrafluoroborate unit) to give N‐(n‐octyl)acetamide in an excellent yield on the basis of the starting octyldibenzothiophenium tetrafluoroborate unit in 4 . The cationic polymerization of glycidyl phenyl ether was also carried out in the presence of poly(S‐methyl‐2‐vinyldibenzothiophenium tetrafluoroborate) or poly(S‐n‐octyl‐4‐vinyldiphenylsulfonium tetrafluoroborate) to confirm their moderate thermal latent activity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3928–3933, 2001     

Physicochemical Investigation on a Chelate Polymer

Coordination polymers of Cu(II), Ni(II), Co(II), and Mn(II) with a poly-Schiff base derived from methylene bis-salicylaldehyde (MBSAL) and diamino diphenyl ether (DDE) have been prepared. Magnetic susceptibility, visible and IR spectra, and thermal and electrical conductivities of the chelates have been studied and probable structures assigned to the chelates.     

Epoxy compounds. VIII. Stereoregular and stereorandom polymerization of phenyl glycidyl ether with tertiary amines,and infrared spectra of poly(phenyl glycidyl ether)

Crystalline and amorphous polymers have been obtained from the polymerization of phenyl glycidyl ether in the presence of tertiary amines. The crystalline fraction is high melting and insoluble at room temperature. The amorphous fractions are soluble at room temperature and their molecular weights are found to be ～950 in benzene at 30°C. The yields of the crystalline fraction and the amorphous paste fraction decreased considerably with increasing the catalyst concentration and reaction temperature above 50°C. The yield of the liquid fraction, however, increased with increasing concentration of the catalyst and the reaction temperature. The x-ray diffraction analysis of the crystalline fraction shows that the fraction has 47–50% crystallinity and that its diffraction pattern is similar to that of poly(phenyl glycidyl ether) obtained by Noshay and Price. The infrared spectra of these fractions have been obtained in the region of 650–4000 cm.^?1. These data are compared with those of polystyrene and poly(styrene oxide) and are used to make an assignment of the normal modes of the poly(phenyl glycidyl ether) molecule. On the basis of analyses of polystyrene and poly(styrene oxide), and a study of the combination bands, it has been possible to make a fairly satisfactory assignment of all of the benzene ring fundamentals of the CH₂, CH, and skeletal modes.     

Synthesis of silicon-containing vinyl ether monomers and oligomers and their photoinitiated polymerization

Silicon-containing divinyl ether monomers were synthesized by the addition reaction of glycidyl vinyl ether ( 1 ) with various silyl dichlorides using tetra-n-butylammonium bromide (TBAB) as a catalyst. The reaction of 1 with diphenyl dichlorosilane gave bis-[1-(chloromethyl)-2-(vinyloxy)-ethyl]diphenyl silane ( 3a ) in 89% yield. Polycondensations of 3a with terephthalic acid were also carried out using 1,8-Diazabicyclo[5.4.0]-7-undecene (DBU) to afford silicon-containing polyfunctional vinyl ether oligomers ( 5 ). A multifunctional Si-monomer with both vinyl ether and methacrylate groups ( 7 ) was prepared by the reaction of 3a with potassium methacrylate using TBAB as a phase transfer catalyst. Photoinitiated cationic polymerizations of these vinyl ether compounds proceeded rapidly using the sulfonium salt, bis-[4-(diphenyl-sulfonio)phenyl]sulfide-bis-hexafluorophoshate (DPSP), as the cationic photoinitiator in neat mixtures upon UV irradiation. Multifunctional monomer 7 with both vinyl ether and methacrylate groups showed “hybrid curing properties” using both DPSP and the radical photoinitiator, 2,4,6-trimethylbenzoyl diphenylphoshine oxide (TPO). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3217–3225, 1997     

Study of chemical processes in the modification of epoxide polymers by aluminum oxide

The processes occurring during the modification of epoxy polymers by various polymorphic aluminum oxide modifications (γ-AlO(OH), γ-Al₂O₃, α-Al₂O₃) with epoxy groups were studied by the methods of IR Fourier spectroscopy, chemical analysis, and differential scanning calorimetry (DSC) by an example of a model compound (phenyl glycidyl ether). Two types of interactions were revealed: a direct chemical reaction of phenyl glycidyl ether with the surface hydroxy groups of alyminum oxide, and phenyl glycidyl ether homopolymerization. By processing by graphical method the data of chemical analysis on the diminishing in amount of epoxy groups in the course of the polycondensation reaction the value of activation energy 106–110 kJ mol⁻¹ of the process of phenyl glycidyl ether interaction with aluminum γ-oxide was determined.     

Kinetics of Photocationically Curable Formulations Involving Glycerol Diglycidyl Ether and Phenyl Glycidyl Ether

Kinetic analysis of formulations based on glycerol diglycidyl ether and phenyl glycidyl ether were carried out in the presence of sulfonium salt as initiator at 35 mW cm^?2using photo differential scanning calorimeter and the final conversion was found to increase with an increase in phenyl glycidyl ether content. The effects of formulation monomer ratios at three different temperatures were studied. The variations in the observed kinetic parameters can be related to increase in mobility of reactive species with temperature, distance of counter ion from the propagating cationic center, as well as extent of crosslinking reaction which controlled the course and duration of the reaction. The applicability of autocatalytic kinetic model was also evaluated and the system underwent early gelation and the activation energy decreased with an increase in phenyl glycidyl ether content. Analysis of stable photocured films containing glycerol diglycidyl ether and phenyl glycidyl ether showed better thermal stability than rigid films obtained with glycerol diglycidyl ether.     

Multivariate resolution of rank-deficient near-infrared spectroscopy data from the reaction of curing epoxy resins using the rank augmentation strategy and multivariate curve resolution alternating least squares approach

A model of the curing reaction between phenyl glycidyl ether (PGE) and aniline as the curing agent was studied isothermally at 95 °C and monitored in situ by near-infrared spectroscopy (NIR). The spectra were recorded every 5 min. The ubiquitous problem of rank deficiency in reaction network systems was solved by assembling an augmented column-wise matrix containing five process runs from different initial conditions. The data were analyzed using a two-way multivariate curve resolution alternating least squares method (MCR-ALS). Initial estimates of spectra required by MCR-ALS were given by a SIMPLe-to-use Interactive Self-modeling Mixture Analysis (SIMPLISMA) approach. The reactants, product and intermediate spectra were successfully resolved and the concentration profiles properly represented the system studied. The performance of the model was evaluated by two parameters: ALS lack of fit (lof=0.88%) and explained variance (R²=99.99%). To validate the MCR-ALS results, the similarity coefficients (r) between the recovered spectra and the pure species spectra were calculated. These were: PGE (r=0.998), aniline (r=0.994) and tertiary amine (r=0.999).     

Influence of solvent on conformational equilibrium in phenyl glycidyl ether

The conformational equilibrium in phenyl glycidyl ether in aprotic solvents was studied by the PMR method over a broad range of changes in the values of the dielectric constant. It was shown that the parameters of the multiplet of noncyclic methylene protons in the PMR spectrum of phenyl glycidyl ether are a sensitive indicator of the position of the conformational equilibrium in the glycidyl fragment. The specific interaction of the molecules of aromatic solvents with the epoxide ring has been discovered.Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 21, No. 2, pp. 245–247, March–April, 1985.     

缩酮胺合锌催化二氧化碳和氧化环己烯共聚

二氧化碳作为单体与环氧化物的共聚反应近年来越来越受到重视 .该反应不经过高耗能的还原过程 ,二氧化碳利用率高 ,所得到的产物聚碳酸酯在塑料、弹性体、涂料、胶粘剂、食品包装材料和生物降解材料等方面有广泛的应用 .二氧化碳与氧化环己烯的交替共聚物聚碳酸亚环己酯玻璃化转变温度较高 (Ｔｇ 为 1 2 0℃ ) ,热分解温度达 2 1 0℃以上[1] ,是一种性能优良的高分子材料 .Ｃｈｅｎｇ等于 1 998年首次报道了一种缩酮胺合锌催化剂[2 ] .它是由 β 二酮 (乙酰丙酮 )与 2 ,6 二异丙基苯胺为原料合成的 ,具有西佛碱结构 ,用于二氧化碳与氧化环己…     

Kinetic and Quantum-Chemical Study of Oxirane Ring Cleavage with Acids

Kinetic and thermodynamic parameters of the reactions of phenyl glycidyl ether and epichlorohydrin with bis(alkylpolyethylene glycol) ether of orthophosphorus acid (oxyphos KD-6) are established. It is shown that the difference in the reactivity of the oxiranes is caused by the electronic effects of substituents and the protonation by the phenolic oxygen atom of phenyl glycidyl ether. Basic solvents decrease the reactivity of the systems. Based on AM1 semiempirical quantum-chemical calculations, a hydroxycarbocation mechanism of the oxirane ring opening was proposed, involving initial formation of unstable cis- and trans-oxonium structures.     

Relative reactivity of primary and secondary amine hydrogen atoms in the reaction between aniline and phenyl glycidyl ether: The effect of ethanol and other additives and the modifying effect of benzene as solvent

The relative reactivity ratio (k₂/k₁) for the secondary and primary amine hydrogen atoms in the neat reaction between aniline and phenyl glycidyl ether was 0.30. This is significantly lower than a recently reaffirmed random value of 0.5 for this system. The ratio is sensitive to added ethanol and decreased with increasing concentration to a limiting value of about 0.20. With benzene as solvent, the effect of added ethanol was more complex, and a low concentration provided a value of 0.45 which decreased with increasing concentration. Other hydroxy additives behaved similarly, but boron trifluoride appears to have no effect on this ratio.     

缩水甘油苯基醚-缩水甘油正丁基醚共聚物磺酸钠的合成及表面活性

缩水甘油苯基醚-缩水甘油正丁基醚共聚物磺酸钠的合成及表面活性;缩水甘油苯基醚-缩水甘油正丁基醚共聚物磺酸钠; 合成; 表面性质; 胶束     

Metal-free synthesis of reactive oligomers by ring-opening oligomerization of glycidyl phenyl ether initiated with tetra-n-butylammonium fluoride in the presence of various protic compounds

Metal-free ring-opening oligomerizations of glycidyl phenyl ether (GPE) were performed with tetra-n-butylammonium fluoride (n-Bu₄NF) as an initiator in the presence of protic compounds (RHs) as chain transfer agents (CTAs). The RHs having pKa between 4.66 and 15.5 enabled to serve as the CTA in this oligomerization system, leading to reactive oligomers with relatively controlled molecular weights having narrow molecular weight distributions bearing functional groups such as alkene, benzyl ether, alkyne, ester and methacrylate groups at initiating end.     

Polymers from aryl glycidyl ethers

High molecular weight, linear polyethers were prepared by polymerizing a series of ring-substituted phenyl glycidyl ethers by using the ferric chloride–propylene oxide and dibutylzinc–water catalyst systems. The α-naphthyl, β-naphthyl, p-phenylphenyl, the o-, m-, and p-methyl, and the o- and p-chlorophenyl polymers resemble the parent polymer in that they are readily crystallizable polyethers which have melting points above 170°C. The other substituted poly(phenyl glycidyl ethers), including the o- and p-isopropyl, p-tert-butyl, p-octyl, and 2,4,6-trichloro derivatives show much less tendency to crystallize and are lower melting. The x-ray and electron diffraction data established that poly(o-chlorophenyl glycidyl ether) crystallizes in an orthorhombic unit cell; data obtained in a parallel study of unsubstituted poly(phenyl glycidyl ether) did not allow assignment of a specific structure.