Inscrição na biblioteca: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Effect of Processing Temperature on Radiative Properties of Polypropylene and Heat Transfer in the Pure and Glassfibre Reinforced Polymer

Get access (open in a dialog) DOI: 10.1615/IHTC15.rad.008207
pages 7035-7049

Resumo

Polypropylene is considered as an appropriate polymer matrix for advanced thermoplastic composite materials which have some advantages in various engineering applications. Wide-range infrared radiative properties of polypropylene are important for combined heat transfer modeling in these composite materials. Five samples of polypropylene obtained at various processing temperatures from 40 to 120 oC are studied using the measurements of both the normal-hemispherical reflectance and normal-hemispherical transmittance of the samples in the wavelength range from 0.67 to 16.7 ?m. The analysis of radiative properties of polypropylene takes into account its specific morphology formed during processing at elevated temperatures. It appears that both morphology and short-wave (visible and near-infrared) radiative properties of polypropylene are sensitive to the processing temperature and there is a significant scattering of radiation in this range. A theoretical analysis based on the Mie theory showed that numerous thin lamellas are responsible for predominant scattering in this range. A considerable resonance scattering is also observed in the local spectral ranges of near-infrared absorption peaks. An example 1-D transient heat transfer problem is solved using the P1 approximation for radiative transfer in the infrared sub-ranges of semi-transparency. A comparison of calculated temperature fields in the layers of pure polypropylene and polypropylene reinforced by glass fibers showed the predominant role of the increase in thermal conductivity as compared with partial transparency of pure polypropylene in the infrared.