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

The role of microcrystalline structure on optical scattering characteristics of semi-crystalline thermoplastics and the accuracy of numerical input for IR-heating modeling

“…4 (b) that shows the T λ-directional values of the samples with different X c (%). The same trend from both the analyses are in good agreement with [12,17] where it was concluded that the size of a scatterer in PP semicrystalline polymer is probably too small. Therefore the optical scattering becomes negligible in MIR range due to the increase in wavelength as the size of the scatterers in PP get considerably smaller than the applied wavelength.…”

“…A similar trend was also observed in [17] where the transmission characteristics of semi-crystalline polypropylene (PP) studied and reported that the effect of optical scattering becomes ineffective with an increase in the wavelength of transmitted radiation especially in MIR range. It was also concluded in [17] that the crystalline lamellae plays a key role in optical scattering phenomenon in the PP polymer medium. The change in transmission behavior of the polymer is due to optical scattering phenomenon that is induced by different X c (%) as only the directly-transmitted light is measured in T λ-directional .…”

“…Although the experimental analyses in [16] also revealed that the scattering characteristics of the material with the same X c (%) changes dramatically in the spectral range of 0.4-1 μm, no explanation was given why the optical scattering behavior changes under varying wavelength and at a constant crystallinity. A similar wavelength-dependent optical scattering relation was observed in [17,18] where it was proposed that the microcrystalline structure, particularly spherulites or their substructures such as lamellae, are responsible for the optical scattering.…”

“…Therefore the optical scattering becomes negligible in MIR range due to the increase in wavelength as the size of the scatterers in PP get considerably smaller than the applied wavelength. Based on the findings in the current study and in [12,17,18] it may be concluded that the identification of scatterer is of prime importance to understand the optical scattering phenomenon in semi-crystalline unfilled thermoplastics adequately.…”

“…The PE polymer in the form of pellets was injection molded and the plate-like PE samples with dimensions of 78 × 78 × 2.2 mm were fabricated. The main reason to fabricate samples via injection molding is to obtain void free samples as the void formations may affect the optical properties of polymers as reported in [12,17]. The injected plate-like samples were then cut into small pieces and compressed in order to obtain thin samples with controlled thickness.…”