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Polyvinylidene fluoride (PVDF)/multiwalled carbon nanotube (MWCNT) composites were prepared by using twin screw extruder at various (0-5 wt %) MWCNT loadings. Field Emission Scanning Electron Microscope (FESEM) micrographs showed a relatively good dispersion and random distribution of MWCNT in PVDF matrix. The physical and dielectric properties increased gradually with the increase in MWCNT content but the thermal stability decreased. The DSC result revealed the increase in crystallinity of the PVDF matrix. Wide angle X-Ray diffraction (WAXD) result showed a large shoulder at 2θ of 20.78° with increasing in MWCNT content. The experimental percolation threshold for the surface resistance of PVDF/MWCNT composites were estimated and clearly observed at 4 wt % of MWCNT loading. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

A new approach towards the recycling of waste ground rubber tire (WGRT) powder was demonstrated in this study by introducing the polypropylene/ waste ground rubber tire (PP/WGRT) foaming method by using CO2 as the foaming agent in an extrusion foaming process. The regression models were constructed to study the relationships between the foam structure (i.e., void fraction, average cell size, and cell density) of foamed PP/WGRT blends, the processing parameters (extruder's die temperature and CO2 concentration), and WGRT content by applying a three-factor central composite design (CCD) statistical approach. The response surface plots generated using the regression models allow the rapid selection of the proper process parameters to obtain microcellular PP/WGRT blends with the desired density and morphology. [ABSTRACT FROM AUTHOR]

In this article, the possibility of obtaining the recycled material based on waste polypropylene (WPP) and waste ground rubber tire powder (WGRT) has been studied. It has been proved that partially replacing WPP with PP-g-MA increased the elongation at break of WPP/WGRT blends, whereas decreased the thermal stability. The presence of compatibilizer increased the elongation at break and thermal stability of WPP/WGRT blends, whereas decreased the processing flowability, as revealed by using universal testing machine (UTM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and capillary rheometer. Moreover, the tendency of the change became more obvious with the content of PP-g-MA and compatibilizer or with the combination of PP-g-MA and compatibilizer. In addition, the improvement of the nonpolar compatibilizer (SEBS) in properties of WPP/WGRT blends was better than that of the polar compatibilizer (SEBS-g-MA). [ABSTRACT FROM AUTHOR]

Proposes two models for describing heat transfer and temperature profiles in single and modular self-wiping co-rotating twin-screw extruders. Calculated heat transfer coefficients on the barrel and screw surface; Comparison of the values of the heat transfer coefficients from the model with those from literature; Screw configurations used.