In situ real-time study of crosslinking kinetics in thermal and microwave fields

Mijović, Jovan; Corso, William V.; Nicolais, L.; d’Ambrosio, Guglielmo

doi:10.1002/(sici)1099-1581(199804)9:4<231::aid-pat747>3.0.co;2-w

Cited by 27 publications

(13 citation statements)

References 5 publications

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“…Remote sensing systems have been developed for the measurement of infrared spectra during processing of polymer samples [5,[20][21][22][23][24][25]. The detection systems used near-infrared transmitting optical fibres as the spectroscopic probes, which were remotely coupled to an infrared spectrometer.…”

Section: Infrared Spectroscopymentioning

confidence: 99%

“…Several investigations have reported reaction rate enhancement, reduced gelation and vitrification times, different reaction temperature ranges and different reaction mechanisms for microwave curing compared with thermal curing [4][5][6][7][8][9][10][11][12][13][14][15]. Opposing studies have observed no difference in reaction kinetics for microwave and thermal processing of a range of polymer systems and have proposed that reaction pathway is independent of processing technique [16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

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Development of a microwave calorimeter for simultaneous thermal analysis, infrared spectroscopy and dielectric measurements

Nesbitt¹,

Navabpour²,

Degamber³

et al. 2004

Meas. Sci. Technol.

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An instrument has been developed for monitoring cure processes under microwave heating conditions. The main function of the instrument was a calorimeter for performing microwave thermal analysis. A single model resonant cavity was used as the heating cell in the microwave calorimeter. Thermal analysis measurements were obtained by monitoring the variation in the microwave power that was required to maintain controlled heating of the sample. The microwave thermal analysis data were analogous to conventional differential scanning calorimetry measurements. The dielectric properties of the sample, as a function of the extent of cure, have been obtained using perturbation theory from the changes in resonant frequency and quality factor of the microwave cavity during heating. Additionally, remote sensing fibre-optic probes have been employed to measure real time in situ infrared spectra of the sample during the cure reaction. In this paper, we describe the design and operation of the microwave calorimeter. Examples of experimental results are also presented.

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Section: Infrared Spectroscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of a microwave calorimeter for simultaneous thermal analysis, infrared spectroscopy and dielectric measurements

Nesbitt¹,

Navabpour²,

Degamber³

et al. 2004

Meas. Sci. Technol.

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“…Several epoxies were heated using the microwave reactor,9 a Multi‐mode Microwave Reactor“Plazmatronika (microwave frequency: 2.45 GHz, maximum of microwave power: 600 W),11 with connected thermometer. The power of the reactor during synthesis was programmed on constancy level 40% independent from mixture compositions; these reactions were conducted in an atmosphere of argon 12, 13…”

Section: Resultsmentioning

confidence: 99%

Synthesis of solid epoxy resins base on BPC II and bisphenol A using conventional heating equipment and microwave

Brzozowski

Staszczak

Hadam

et al. 2006

J of Applied Polymer Sci

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New solid state epoxy resins based on diglycidyl ether of 1,1-dichloro-2,2 bis (4-hydroxyphenyl), ethylene (BPC) and BPA epoxy resins in the reaction with BPC and BPA were developed. Solid epoxy resins were synthesised by the use of two different heating methods: conventional and microwave reactor. The use of microwave radiation as novel heating medium as an alternative to the conventional methods, which provide a quicker and more effective synthesis. The solid epoxies have high melting points higher than 100°C and the polycondensation degree remains between n ϭ 4 -12. Epoxy value stays low and occurs around 0,02-0,1. BPA epoxy resins and diglycidylether of BPC II were compared in terms of reaction speed. It can be seen that the reaction of BPC diglycidylether occurs approximately 20% quicker given the same reaction conditions of temperature, and balance of catalyst.

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“…Although DSC has been the method most used for thermal characterization in the literature, other methods are rising in popularity. Some of these methods are based on spectroscopic methods, such as Fourier transform infrared [22,23], and others are based on electromagnetic and dielectric techniques [24 -26].…”

Section: Introductionmentioning

confidence: 99%

Experimental modeling of the cure behavior of a formulated blend of DGEBA epoxy and C12-C14 glycidyl ether as a reactive diluent

Ali

Hammami

2005

Polym. Compos.

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Microwave curing of polymer matrix composites has been suggested as an attractive substitute for conventional thermal curing. Formulations of epoxy and reactive diluents have the advantage of better wettability and uniform fiber impregnation. However, higher peak exotherms in large masses, and thus thermal overshoot, presents a challenge for cure cycle optimization. Therefore, building a reliable curing model will not only predict the behavior of these materials during actual processing, but also facilitate numerical modeling of the process and comparison of other resin formulations. In this study the effect of the reactive diluent on the isothermal cure kinetics of low viscosity epoxy was investigated using differential scanning calorimetry (DSC). A formulated blend of diglycidyl ether of bisphenol A (DGEBA) and C 12 -C 14 aliphatic glycidyl was cured using diethylene triamine as the curing agent. Using a standardized procedure, ISO 113571-5, the epoxy formulation was isothermally cured at several temperatures and the heat flow monitored and recorded. Using the heat flow data from DSC, the rate of cure was determined experimentally and a proper autocatalytic model with a total order of about 2.3 was fit to describe the process. Leastsquare regression and isoconversion methods were used to find the model parameters and the activation energy, respectively. The accuracy of the model shows fine correlation with experimental data. By comparison to other epoxy resin without diluents, the analysis of the data shows that the reactive diluent increased the curing rate, while the values of activation energy and process parameters remained within the typical values of epoxy formulations. Based on these data, the future use of these types of resins in nonthermal curing of epoxy matrix composites is discussed. POLYM. COMPOS., 26: 593-603, 2005.

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In situ real-time study of crosslinking kinetics in thermal and microwave fields

Cited by 27 publications

References 5 publications

Development of a microwave calorimeter for simultaneous thermal analysis, infrared spectroscopy and dielectric measurements

Development of a microwave calorimeter for simultaneous thermal analysis, infrared spectroscopy and dielectric measurements

Synthesis of solid epoxy resins base on BPC II and bisphenol A using conventional heating equipment and microwave

Experimental modeling of the cure behavior of a formulated blend of DGEBA epoxy and C12-C14 glycidyl ether as a reactive diluent

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