Abstract:: :: : Blends of polypropylene and polystyrene compatibilized with styrene-butadiene-styrene (SBS) or styrene-ethylene/butylene-styrene (SEBS) copolymers were studied. The morphology of these blends was studied by Scanning Electron Microscopy. Emulsion curves relating the average radius of the dispersed phase to the concentration of compatibilizer added to the blend were obtained. The rheological behavior of the blends was studied by small amplitude oscillatory shear, and correlated to the morphological observ… Show more
“…This value is stable when the temperature increases from 180 until 220 °C. The comparison of these results with an experimental value of interfacial tension (6.25 mN/m) obtained in the same conditions and deduced from the literature [37] indicates the existence of a slight difference. However, the Palierne model allows a prediction which is qualitatively in agreement with the experimental observations.…”
Blends of polypropylene (PP3) and polystyrene (PS) were studied and, their rheological behavior was determined and discussed in detail. The interfacial tension between the blend components was evaluated from the rheological data and the storage modulus by using two well-known models: Palierne model and Choi-Schowalter equation. The theoretical predictions were compared with experimental data obtained from PP3/PS blends. The obtained results showed that the Palierne model could predict the rheological and viscoelastic properties of the considered polymer blends. In addition, the interfacial tensions between PP3 and PS were evaluated and compared with those cited in the literature. It was also found that the Palierne model was more accurate than Choi-Schowalter one in determining the interfacial tension.
“…This value is stable when the temperature increases from 180 until 220 °C. The comparison of these results with an experimental value of interfacial tension (6.25 mN/m) obtained in the same conditions and deduced from the literature [37] indicates the existence of a slight difference. However, the Palierne model allows a prediction which is qualitatively in agreement with the experimental observations.…”
Blends of polypropylene (PP3) and polystyrene (PS) were studied and, their rheological behavior was determined and discussed in detail. The interfacial tension between the blend components was evaluated from the rheological data and the storage modulus by using two well-known models: Palierne model and Choi-Schowalter equation. The theoretical predictions were compared with experimental data obtained from PP3/PS blends. The obtained results showed that the Palierne model could predict the rheological and viscoelastic properties of the considered polymer blends. In addition, the interfacial tensions between PP3 and PS were evaluated and compared with those cited in the literature. It was also found that the Palierne model was more accurate than Choi-Schowalter one in determining the interfacial tension.
“…Blends of polyolefins (PO) and polyethylene terephthalate (PET) have recently attracted considerable research activity [1][2][3][4][5][6] since both materials are among the most frequently used thermoplastics, especially as packaging materials. Due to their broad-scale application, PO/PET mixtures represent a significant part of postconsumer waste.…”
Section: Introductionmentioning
confidence: 99%
“…To overcome problems due to immiscibility, a compatibiliser is employed. For that purpose, different compatibilising methods have been used, involving functionalization of the blend components before blending, 1,[11][12][13] the addition of a copolymer during blending [2][3][4][14][15][16][17] and particularly reactive melt blending [18][19][20][21] . Unlike the conventional two-step processes, in which the compatibiliser is synthesised first, and then added to a blend, reactive compatibilisation is a one-step process, in which the functionalities present on the polymers are utilised to form a copolymer in situ while compounding the blend 22 .…”
Both polypropylene (PP) and polyethylene terephthalate (PET) constitute a significant portion of post-consumer waste. To improve the recycling of immiscible PP/PET blends, a compatibiliser should be utilised. The steady shear flow properties of unmodified and modified PP/PET blends having up to 50 wt.% PET were investigated and compared in this study. Three types of PPs with different flow properties were used to ascertain the influence of the matrix on the blend's rheology. The effect of modification on the rheological properties was evaluated in two ways - firstly, the addition of 1 wt.% of maleic anhydride (MA), and secondly, the use of already modified polypropylene. According to the morphological observations, an improvement in compatibility was found in both cases. The shear viscosity and the first normal stress difference were measured using a rotational cone and plate rheometer at 265°C (when both PET and PP are molten), and 245°C (when only PP has melted). Completely different behaviour was observed under these two temperature conditions. At 265°C, the shear viscosity decreases with PET content in the blend, while at 245°C it increases, thus recalling the behaviour of particle-filled systems. The addition of maleic anhydride affects the shear viscosity in various ways; a decrease, an increase, and some almost unchanged values were obtained. Concerning the first normal stress difference, an even more complex situation occurs, and the effect of modification by MA is also ambiguous. Furthermore, the deviations from the log-additivity rule were evaluated in terms of the shear viscosity and the first normal stress difference. From the results, it can be supposed that PP-X/PET samples were compatibilised successfully, and strong interphase interactions could be expected. Finally, the yield values of shear stress determined at 245°C showed a generally increasing tendency with increasing PET content.
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