دانلود رایگان مقاله تفکیک نانوذرات هسته - پوسته سیاه کربن از لاستیک زباله تجزیه در اثر حرارت نور

Abstract

The separation of core-shell structured carbon black (CBlp) nanoparticles from waste tires was investigated by applying a reactive extrusion process. The polymeric shell consisting primarily of crosslinked rubber and loosely bound rubber could be selectively separated by varying the extrusion temperature to 260, 280 and 300 °C. The structure, chemical composition and structure of the separated CBlp were characterized using thermo-gravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and dynamic light scattering. The crosslinked structure was persevered in the rubber shell of CBlp after extruding at 260 °C. A layer of loosely bound rubber was observed only in the rubber shell when extruded at 280 °C and 300 °C. The composition of the bound rubber layer is also dependent on the processing temperature.

4. Conclusions

Core-shell structured CBlp particles were derived from waste tire rubber via a reactive extrusion process. The structure and composition of the separated carbon black from tire rubber at three different pyrolysis temperatures were characterized. The TEM observations and TGA analysis revealed that there are primary and destroyed loosely bound rubber existing on the surface of CBlp-300, while the rubber shell of CBlp-280 includes primary bound rubber, loosely bound rubber and some free rubber chains. The three-dimensional crosslinked rubber network on the surface of CBlp-260 is well-preserved during the extrusion process. The structure of CBlp is affected by the composition and thickness of the rubber shell. The samples treated with higher temperatures exposed more additives to the surface of the CBlp and exhibited higher contents of S, Zn and N. The average particle size of CBlp increased with a decrease in the special surface area as the extrusion temperature was reduced. This reflects the effect of the extrusion temperature on the structure of the rubber shell. This study demonstrates the interfacial interactions of carbon black with the rubber matrix by illustrating the structural change of bound rubber layers at different extrusion temperatures, and also provides a facile route for recycling waste tire rubbers into useful products.