Dynamic Measurements of Complex Permittivity and Temperature During Microwave Heating

Ollivon, Michel

doi:10.1109/mwsym.1985.1132063

Cited by 2 publications

(3 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Figure 13 are shown the variations of the dielectric constants of the DGEBA/DDA-based composite, as a function of temperature during cure, measured by means of a microwave method (Ollivon, 1985;Ollivon et al, 1988). The average value of the permittivity of the composite is about 4.…”

Section: Buildup Of the Processmentioning

confidence: 99%

Build-up and Optimization of a Homogeneous Microwave Curing Process for Epoxy-Glass Composites

Outifa¹,

Jullien²,

Moré³

et al. 1995

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

To obtain homogeneously microwave cured epoxy-glass composite samples greater than the wavelength of radiation, physical considerations and mathematical calculations of the wave propagation in dielectric filled waveguides show that a single-mode travelling wave is required. According to this conclusion, a process is developed, using matched tapered transitions at airmaterial incoming and material-air outgoing interfaces, to reduce reflections and nonuniformities. Mould materials are selected with a permittivity less than that of the material to be cured. Experiments show that satisfactorily homogeneously cured samples can be obtained through this way.

show abstract

Section: Buildup Of the Processmentioning

confidence: 99%

Build-up and Optimization of a Homogeneous Microwave Curing Process for Epoxy-Glass Composites

Outifa¹,

Jullien²,

Moré³

et al. 1995

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…1,2,5,12,13 These are the imaginary and real components of the complex permittivity and their ratio, the loss tangent ͑tan ␦͒. The greater a material's loss tangent is, the greater will be the heating rate in a given microwave field.…”

Section: Theory Of Microwave Heatingmentioning

confidence: 99%

“…[1][2][3][4] The extensive use of microwave energy in heating is due to the significant advantages it provides over conventional methods. 5 These include the potential for highly uniform heating, the ability to achieve exceptionally rapid heating rates in certain materials, and improved levels of process control over conventionally heated systems.…”

Section: Introductionmentioning

confidence: 99%

Development of a novel instrument for microwave dielectric thermal analysis

Nair

Parkes

Barnes

et al. 2006

Review of Scientific Instruments

View full text Add to dashboard Cite

The advantages of microwave heating in industrial processing are becoming more widely appreciated and the technique is of increasing commercial significance. However, knowledge of a material's dielectric properties as a function of temperature is of considerable importance as they determine the efficiency with which the material converts microwave energy into heat. This article describes the development of a novel instrument for a new form of thermal analysis, microwave dielectric thermal analysis ͑MDTA͒ in which the sample is heated not conventionally but by microwaves, while its dielectric properties at microwave frequencies are determined quasisimultaneously using a network analyzer. A plot of the dielectric properties against temperature then gives the MDTA curve. The fundamental principle underlying the use of MDTA is that not only do a material's dielectric properties ͑both the real and imaginary parts of the complex permittivity͒ alter ͑generally smoothly͒ as a function of temperature but dramatic differences can be found when chemical or physical changes occur. MDTA measures the sample's dielectric properties as a function of temperature before, during, and after the chemical and/or physical changes occurring as it is heated in the microwave field and thus provides a unique way of studying them. Furthermore, due to the quasisimultaneous nature of the measurements, MDTA can also make a valuable contribution to the investigation of the so-called "microwave effect" anomalies that occur when certain materials are heated in a microwave field. We show that the technique can be used to study a wide range of thermal transformations, including solid-solid phase changes, melting, and chemical reactions, e.g., dehydration, via the complex permittivity-temperature profiles generated in MDTA.

show abstract

Dynamic Measurements of Complex Permittivity and Temperature During Microwave Heating

Cited by 2 publications

References 5 publications

Build-up and Optimization of a Homogeneous Microwave Curing Process for Epoxy-Glass Composites

Build-up and Optimization of a Homogeneous Microwave Curing Process for Epoxy-Glass Composites

Development of a novel instrument for microwave dielectric thermal analysis

Contact Info

Product

Resources

About