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Study on the Recycling ofABS Resins: Simulation of Reprocessing and Thermo-oxidation

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Processability, morphology, optical, and mechanical properties of acrylonitrilebutadiene- styrene (ASS) polymers were studied by simulation of its reprocessing and service life. A series of ASS samples were prepared by melt-mixing of SAN and g-ASS. All specimens were characterized by melt mass-flow rate (MFR) measurements, tensile testing, impact strength (Izod), Fourier transform infrared (FTlR) spectroscopy. colour spectrophotometry (data of L", a*, and b*) and transmission electron microscopy (TEM) techniques. Reprocessing and thermo-oxidative ageing clearly alter the elongation-at-break, impact strength and yellowness index of the polymers. These changes observed at a macroscopic scale have been related to chemical alterations in the structure of ASS. TEM Micrographs indicated no significant changes in the status of rubber (PS) phase. The PS phase was demonstrated to be the initiation point of the degradative processes induced by processing, service life, and recycling. The results of the FTIR showed that upon processing of ASS, cross-linking and chain scission of rubber phase was the governing degradation and yellowing mechanisms. Thermo-oxidative ageing degradation has affected the degree of yellowing of the polymer more severely. Thus, it may be deduced that the changes occurring during service life of ASS are part of the life cycle which mostly affect its further recycling possibilities and performance in second-market applications.

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