Infrared Radiation Applied to Polymer Processes

Maoult, Yannick Le; Schmidt, Fabrice

doi:10.1002/9781119116288.ch13

Cited by 6 publications

(8 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For each temperature step, the temperature profile on the PET surface was recorded using an IR camera (FLIR SC325). PET was chosen as a reference material for these analyses as, it is opaque in the operating range of a typical IR camera in contrast to PE polymer [20]. Hence, a reliable surface temperature on PET could be obtained via IR thermographic measurements [21].…”

Section: Test Methodology For Temperature-dependent Spectroscopic Meamentioning

confidence: 99%

“…Considering the fact that a halogen IR lamp used for injection stretch blow molding (ISBM) processes has a temperature around 2000-2600 K, maximum emission wavelength (λ max (μm)) of the lamp should be theoretically around 1.1-1.4 μm, regarding to Wien's displacement law [22,23]. In addition, nearly 95% of total energy emitted by such an IR lamp lies between λ max /2 and 5λ max which reflects a spectral range roughly between 0.6 and 7 μm [20,22,23]. It may therefore be concluded that the temperature dependence in the thermo-optical properties of semi-crystalline PE seen in NIR range may have a significant effect on the amount of absorbed energy, due to both high level of emitted radiation by IR lamp and the variation in its absorption characteristics.…”

Section: Temperature-dependent Thermo-optical Properties Of Pementioning

confidence: 99%

“…Source of the parameter an operating spectral range between 7 and 14 μm [20] that cover two of the narrow spectral bands -around 7.6 and 13.6 μm, respectively-, at which PE has very low transmittance. However, as they are relatively narrow in comparison to the operating range of a typical IR camera, narrow bandpass (NBP) optical filters are necessary for quantitative IR thermographic measurements at these spectrums.…”

Section: Input Parametermentioning

confidence: 99%

“…The back surface temperature was also measured employing the other IR camera, FLIR SC 325. As no filer was mounted in this camera, and it operates between 7.5 and 13.5 μm [20], its measurements were considered as a reference for analyzing the accuracy of the optical filter mounted IR camera. In addition, one TC attached in the middle zone of the back surface for the comparisons.…”

Section: Input Parametermentioning

confidence: 99%

“…However, this is not the case for PE polymer as it is semi-transparent [37,38,46], which is also shown in this study considering its spectroscopic measurements. Simply, the emissivity of semi-transparent materials is a global physical quantity which theoretically represent emission from medium but not from surface [20,47], due to volumetric absorption. In other words, the emitted energy, and thus the value of emissivity, of an opaque material does not change by a change in their thickness, conversely it is strongly affected by a change in the thickness of semi-transparent materials [48] which makes ε surface fundamentally unsound.…”

Section: Experimentalnumerical Comparisons For Ir Heating Of Pe Platementioning

confidence: 99%

See 4 more Smart Citations

A combined experimental and numerical approach for radiation heat transfer in semi-crystalline thermoplastics

Boztepe

Almeida

Gilblas

et al. 2019

International Journal of Thermal Sciences

Self Cite

View full text Add to dashboard Cite

This paper proposes a novel experimental-numerical approach for radiation heat transfer in semi-crystalline thermoplastics. The proposed experimental and numerical approaches were analyzed here for the case of IR heating of linear polyethylene (PE). The challenges for radiation transport in semi-crystalline polymers may be categorized into the two main aspects: optical heterogeneity in polymer medium due to semi-crystalline nature and, semi-transparency in certain type of such polymers, like PE. In this study, we address the temperature dependence in the thermo-optical properties of semi-crystalline thermoplastics concerning its effect as a thermal radiation parameter for radiation heat transfer modeling of such type of polymers. The temperature dependence in the optical properties of PE, namely transmittance and reflectance characteristics, were experimentally analyzed under heating condition and, the temperature-dependent thermo-optical properties of PE was determined. The experimental analyses showed that the change in the thermo-optical properties under heating is related to change in the optical scattering behavior in PE medium since it is strongly affected by its crystalline structure. The radiation heat transfer model was built based on optically homogeneous medium assumption at which the change in the amount of radiative energy absorbed by the PE medium under heating was introduced without modeling how the light scatters inside of the medium. Thus, the effect of optical scattering on the absorption characteristics of PE under varying temperature was taken into account without modeling the spatial distribution of the scattered light intensity at microscopic level, which offers computationally cost-effective numerical solutions. The accuracy of the numerical model was analyzed performing IR heating experiments where IR thermography and thermocouples were employed for the surface temperature measurements. Due to the semi-transparent nature of PE, an experimental method was developed for IR thermography of PE and its accuracy was analyzed. The experimental-numerical comparisons showed that the temperature field on PE can be closely predicted using its temperature-dependent thermo-optical properties. Thanks to the adopted comparative case study, it was demonstrated how the temperature field predictions may deviate from the experimental thermal measurements due to the ignorance of this temperature dependence. Considering any type of monochromatic or polychromatic radiation source, the combined experimental-numerical approach proposed here may be adopted for temperature field predictions and non-invasive surface temperature measurements on the radiatively heated semi-crystalline thermoplastics.-* Corresponding author.

show abstract

Section: Test Methodology For Temperature-dependent Spectroscopic Meamentioning

confidence: 99%

Section: Temperature-dependent Thermo-optical Properties Of Pementioning

confidence: 99%

Section: Input Parametermentioning

confidence: 99%

Section: Input Parametermentioning

confidence: 99%

Section: Experimentalnumerical Comparisons For Ir Heating Of Pe Platementioning

confidence: 99%

See 3 more Smart Citations

A combined experimental and numerical approach for radiation heat transfer in semi-crystalline thermoplastics

Boztepe

Almeida

Gilblas

et al. 2019

International Journal of Thermal Sciences

Self Cite

View full text Add to dashboard Cite

show abstract

Infrared heating modeling of recycled PET preforms in injection stretch blow molding process

Gilblas

Lucin

et al. 2022

International Journal of Thermal Sciences

View full text Add to dashboard Cite

A non-invasive experimental approach for surface temperature measurements on semi-crystalline thermoplastics

Boztepe

Gilblas

Almeida

et al. 2017

AIP Conference Proceedings

Self Cite

View full text Add to dashboard Cite

Most of the thermoforming processes of thermoplastic polymers and their composites are performed adopting a combined heating and forming stages at which a precursor is heated prior to the forming. This step is done in order to improve formability by softening the thermoplastic polymer. Due to low thermal conductivity and semi-transparency of polymers, infrared (IR) heating is widely used for thermoforming of such materials. Predictive radiation heat transfer models for temperature distributions are therefore critical for optimizations of thermoforming process. One of the key challenges is to build a predictive model including the physical background of radiation heat transfer phenomenon in semi-crystalline thermoplastics as their microcrystalline structure introduces an optically heterogeneous medium. In addition, the accuracy of a predictive model is required to be validated experimentally where IR thermography is one of the suitable methods for such a validation as it provides a non-invasive, full-field surface temperature measurement. Although IR cameras provide a non-invasive measurement, a key issue for obtaining a reliable measurement depends on the optical characteristics of a heated material and the operating spectral band of IR camera. It is desired that the surface of a material to be measured has a spectral band where the material behaves opaque and an employed IR camera operates in the corresponding band. In this study, the optical characteristics of the PO-based polymer are discussed and, an experimental approach is proposed in order to measure the surface temperature of the PO-based polymer via IR thermography. The preliminary analyses showed that IR thermographic measurements may not be simply performed on PO-based polymers and require a correction method as their semi-transparent medium introduce a challenge to obtain reliable surface temperature measurements.

show abstract

Infrared Radiation Applied to Polymer Processes

Cited by 6 publications

References 19 publications

A combined experimental and numerical approach for radiation heat transfer in semi-crystalline thermoplastics

A combined experimental and numerical approach for radiation heat transfer in semi-crystalline thermoplastics

Infrared heating modeling of recycled PET preforms in injection stretch blow molding process

A non-invasive experimental approach for surface temperature measurements on semi-crystalline thermoplastics

Contact Info

Product

Resources

About