Analysis of the cure kinetics of epoxy/imidazole resin systems

Heise, Martin; Martin, G. C.

doi:10.1002/app.1990.070390321

Cited by 79 publications

(73 citation statements)

References 17 publications

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“…This value is much lower than the results obtained in previous work 5,19 in which E is also assumed to be constant and Fourier Transform Infrared Spectroscopy (FT IR) or DSC technique is used. Moreover, this value falls within the range of 34.3-63.84 KJ mol À1 obtained with Method II.…”

Section: Comparison Of the Two Methods And The Calculated Curing Kinementioning

confidence: 57%

“…[1][2][3] The adducts were believed to be the catalyst that initiated the etherification reactions which cross-link the epoxy resins and determine the final properties of the network. Previous work 5 showed that the formation of adduct was necessary prior to the etherification reaction. Thus, low EMI-2,4 concentrations can be used to analyze the etherification reactions by suppressing the adduct formation.…”

Section: Theoretical Analysismentioning

confidence: 99%

“…The kinetics of imidazole/resin systems has been widely studied by using isothermal or dynamic DSC technique. [1][2][3][4][5] But their studies were all based on the assumption of a constant E and the whole reaction of curing was considered as a single kinetic process (Method I). Therefore, the calculated E is the apparent activation energy of the global reaction.…”

mentioning

confidence: 99%

“…and were performed at temperatures ranging from 310 to 510 K at different heating rates of 5,10,15,20 C/ min. The reaction was considered to be complete when the rate curve leveled off to a baseline.…”

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confidence: 99%

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Mechanism and Kinetics of Epoxy-Imidazole Cure Studied with Two Kinetic Methods

Zhou

Jin

et al. 2005

Polym J

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ABSTRACT:Curing kinetics and mechanism of the diglycidyl ether of bisphenol-A (DGEBA) initiated with 2-ethyl-4-methylimidazole (EMI-2,4) were studied with two methods by using differential scanning calorimetry (DSC). Method I and Method II were deduced by assuming a constant E and a variable E, respectively. With Method I, the cure reaction activation energy E, the frequency factor A and the overall order of reaction m þ n are calculated to be 49.03 KJ mol À1 , e 14:5 and 1.22, respectively. With Method II, E is proved to decrease initially, and then increase as the cure reaction proceeds, and the value of E spans from 34.3 to 63.84 KJ mol À1 . The variations of E were also used to study the cure reaction mechanism. Method I and Method II are effective as long as they are used in proper aspects. With these two methods used all together, we can have a comprehensive and in-depth understanding of the cure reactions, such as those of the DGEBA/EMI-2,4 system. [DOI 10.1295/polymj.37.833] KEY WORDS Cure Reaction / DSC / Kinetic Method / DGEBA/EMI-2,4 System / Imidazole-cured resins are widely used in the electronics industry as molding and sealing compounds because they exhibit a better heat resistance, a higher modulus, and a wider range of cure temperatures than amine-cured systems. The kinetics of imidazole/resin systems has been widely studied by using isothermal or dynamic DSC technique. [1][2][3][4][5] But their studies were all based on the assumption of a constant E and the whole reaction of curing was considered as a single kinetic process (Method I). Therefore, the calculated E is the apparent activation energy of the global reaction. However, the reaction of curing epoxy resins is normally very complex, such as the change from chemical kinetic control to diffusion control in the advance of the curing, 6,7 and E changed momently. In this work, another method deduced without the assumption of constant E (Method II) was also employed to analyze the dynamic DSC data, then the interpretation of the dependence of E on the extent of reaction in the terms of the reaction mechanisms was also made. As a result, with these two different kinetic methods, which have their particular merits and demerits, used together, we can have a comprehensive and in-depth understanding of the curing kinetics of the DGEBA/EMI-2,4 system. EXPERIMENTALEpoxy resin used in this work was a nominally difunctional epoxy resin, Epon 828 supplied by Shanghai Resin Co. Epon 828 is, basically, DGEBA with the epoxy value of 0.48-0.52 mol/100 g. The structure for DGEBA is shown in Figure 1. The curing agent used was EMI-2,4 supplied by Beijing Chemical Reagent Co. Other agents used were analytically pure grade and were supplied by Beijing Chemical Reagent Co.Approximately 10 mg sample of the mixture of DGEBA and EMI-2,4 was weighed accurately into an aluminum DSC sample pan and then covered with an aluminum lid. The entire operation was carried out in a dry chamber. DSC measurements were carried out by using a Perkin-Elmer DSC-7 system. The DSC ...

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Section: Comparison Of the Two Methods And The Calculated Curing Kinementioning

confidence: 57%

Section: Theoretical Analysismentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Mechanism and Kinetics of Epoxy-Imidazole Cure Studied with Two Kinetic Methods

Zhou

Jin

et al. 2005

Polym J

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“…Kinetic investigation is one of the most important applications of thermal analysis and has been widely conducted using isothermal or dynamic differential scanning calorimetry (DSC) technologies. [13][14][15] Kinetic studies are especially important when fillers are used to predict performances and design curing cycles for the epoxy composites. This ensures that the cured epoxy is able to respect the requirements of its end use applications.…”

Section: Introductionmentioning

confidence: 99%

Curing kinetics, thermomechanical and microwave behaviors of PANI-doped BSA/epoxy resin composites

Belaabed¹,

Lamouri²,

Wojkiewicz

2011

Polym J

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This work focuses on the elaboration and characterization of conducting polymer composites based on polyaniline (PANI) dispersed in an epoxy resin (ER) matrix and cured using an anhydride without a catalyst. PANI-doped benzene sulfonic acid was successfully synthesized in this manner and used as conducting filler. The effect of heating rate and PANI loading level on the curing process was investigated by differential scanning calorimetry in the dynamic mode. Furthermore, the phase structure, viscoelastic behavior and hardness of the composites were explored by dynamic mechanical thermal analysis and Vickers tests. The structure and morphology of the samples were investigated by scanning electron microscopy, which revealed behavior that varied as a function of the concentration of PANI in the composites. Dielectric properties were investigated up to 1 MHz. The electromagnetic shielding effectiveness of the composites was measured in the microwave band from 8 to 18 GHz. It was found that the electrical properties of PANI were influenced by elevated curing temperature of the ER, a variable that significantly affected the composite characteristics. In addition, the dielectric properties, curing parameters, viscoelasticites and electromagnetic behaviors of the composites were affecting by increasing the concentration of PANI filler in the matrix.

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Kinetics study of imidazole-cured epoxy-phenol resins

Chen

Chiu

Lin

1999

J. Polym. Sci. A Polym. Chem.

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The reaction kinetics of diglycidyl ether of bisphenol A (DGEBA) cured with different concentrations of imidazole and bisphenol A (BPA) were investigated by using differential scanning calorimetry. Both dynamic and isothermal DSC were studied. Two initiation mechanisms were found to play roles in the curing reactions. One was based on adduct formation of epoxy groups with pyridine‐type nitrogen and the other was based on ionic complexes of imidazole and BPA. The subsequent propagation was composed of three main reactions, viz. the epoxide/phenol reaction, the acid/base reaction, and the epoxide/R‐O− reaction. A generalized kinetics model was developed and used to predict the conversion of epoxide groups using a wide range of imidazole and BPA concentrations, and cure temperature. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3233–3242, 1999

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Analysis of the cure kinetics of epoxy/imidazole resin systems

Cited by 79 publications

References 17 publications

Mechanism and Kinetics of Epoxy-Imidazole Cure Studied with Two Kinetic Methods

Mechanism and Kinetics of Epoxy-Imidazole Cure Studied with Two Kinetic Methods

Curing kinetics, thermomechanical and microwave behaviors of PANI-doped BSA/epoxy resin composites

Kinetics study of imidazole-cured epoxy-phenol resins

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