Recovery of recycled acrylonitrile-butadiene-styrene, through mixing with styrene-ethylene/butylene-styrene

Recovery of recycled acrylonitrile-butadiene-styrene (ABS) through mixing with styrene-ethylene/butylene-styrene (SEBS) has been studied in this paper. To simulate recycled ABS, virgin ABS was processed through 5 cycles, at extreme processing temperatures, 220 degrees C and 260 degrees C. The virgin ABS, the virgin SEBS, the recycled ABS and the mixtures were mechanically, thermally and rheologically characterized after the various cycles of reprocessing in order to evaluate their corresponding properties and correlate them with the number of cycles undergone. With these data and using Computer Aided Engineering (CAE) the injection process was simulated by obtaining the optimal injection process parameters. Mixtures were injected at two temperatures in a sensorised mold correlating the shrinkage of the parts with temperature. The results show that tensile strength of ABS remains practically constant as the number of reprocessing cycles increases, while in the material injected with SEBS the tensile strength decreases. Concerning the Charpy notched impact strength; the values of the ABS reprocessed at 220 degrees C remain more or less unchanged, while the values for 260 C show a significant decrease. The adhesion of the SEBS causes, in both cases, an increase in impact strength. DSC techniques enabled us to observe how the glass transition temperature (T-g) remains more or less constant regardless of the number of cycles or the temperature, whereas the crosslinking is much greater in the samples reprocessed at 260 C. Finally, the viscosity decreases with each cycle and this decrease becomes even more noticeable with the addition of SEBS, and also that the parts molded at lower temperatures have less shrinkage. (c) 2013 Elsevier B.V. All rights reserved.We would like to thank the Vice-Directorate of Research, Development and Innovation of the Polytechnic University of Valencia for the help granted to the project: "Ternary systems research applied to polymeric materials for the upgrading of waste styrene", Ref: 20091056 within the program of First Projects of Investigation (PAID 06-09) where this work is framed.Peydro, MA.; Parres, F.; Crespo Amorós, JE.; Navarro Vidal, R. (2013). Recovery of recycled acrylonitrile-butadiene-styrene, through mixing with styrene-ethylene/butylene-styrene. Journal of Materials Processing Technology. 213(8):1268-1283. https://doi.org/10.1016/j.jmatprotec.2013.02.012S12681283213

Improved Mechanical Properties of Compatibilized Polypropylene/Polyamide-12 Blends

Compatibilized blends of polypropylene (PP) and polyamide-12 (PA12) as a second component were obtained by direct injection molding having first added 20% maleic anhydride-modified copolymer (PP-g-MA) to the PP, which produced partially grafted PP (gPP). A nucleating effect of the PA12 took place on the cooling crystallization of the gPP, and a second crystallization peak of the gPP appeared in the PA12-rich blends, indicating changes in the crystalline morphology. There was a slight drop in the PA12 crystallinity of the compatible blends, whereas the crystallinity of the gPP increased significantly in the PA12-rich blends. The overall reduction in the dispersed phase particle size together with the clear increase in ductility when gPP was used instead of PP proved that compatibilization occurred. Young's modulus of the blends showed synergistic behavior. This is proposed to be both due to a change in the crystalline morphology of the blends on the one hand and, on the other, in the PA12-rich blends, to the clear increase in the crystallinity of the gPP phase, which may, in turn, have been responsible for the increase in its continuity and its contribution to the modulus.The financial support of the Basque Government (Project IT-611-13) and of the University of the Basque Country (UFI 11/56) is gratefully acknowledged. Nora Aranburu also acknowledges the Basque Government for the award of a grant for the development of this work