Francisco Parres García

PIRÓLISIS DE RESIDUOS DE BIOPLÁSTICOS: PRODUCTOS OBTENIDOS DEL ÁCIDO POLILÁCTICO ( PLA)

ABSTRACT Pyrolysis of bioplastics waste may offer an alternative waste treatment option, allowing the recovery of resources. Bioplastics have taken special interest in the industry. They could be an alternative to conventional petroleum based plastics. Polylactic acid (PLA) is a bioplastic that has gained big interest during the last two decades. Pyrolysis of bioplastics waste may be economically and environmentally attractive. In order to obtain optimal energy recovery with an appropriate composition of emitted products, pyrolysis treatment has to ensure the adequate conditions. In this work, the thermal degradation of PLA was studied by pyrolysis coupled with gas chromatography and mass spectrometry detection. The test conditions allowed to identify and quantify the major compounds produced during thermal degradation of PLA.

Influence of styrene–ethylene–butylene–styrene on the properties of acrylonitrile butadiene styrene–high-impact polystyrene blends:

A binary blend of acrylonitrile butadiene styrene–high-impact polystyrene (ABS–HIPS 50% wt) was prepared on a twin-screw extruder at 190–210°C. The different properties were then analyzed using tensile strength and impact tests, melt flow index, thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR). The analysis of mechanical properties showed a decrease in elongation at break and impact strength. FTIR analysis indicated heterogeneous distribution of the blend in injected pieces and scanning electron microscopic images show heterogeneous distribution of both ABS and HIPS phase. On the other hand, by varying the percentage of styrene–ethylene–butylene–styrene (SEBS) from 10 to 30% wt using a twin-screw extruder at 190–210°C, we have prepared ternary blends of ABS-HIPS-SEBS. The addition of SEBS to the binary system ABS–HIPS allowed us to increase the ductile properties (elongation at break and impact strength), as well as reducing the viscosity.

RECUPERACIÓN DE PLÁSTICOS RECICLADOS MEDIANTE ADICCIÓN DE ELASTÓMEROS TERMOPLÁSTICOS.

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, 220oC and 260oC. The virgin ABS, the virgin SEBS, the recycled ABS and the mixtures were mechanically and thermally characterized after the various cycles of reprocessing in order to evaluate their corresponding properties and correlate them with the number of cycles undergone.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 220oC remain more or less unchanged, while the values for 260oC 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 (Tg) 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 260oC.As conclusion, it is suggested that the people who works handling and dealing with plastic that, when possible, use low temperatures of transformation of ABS instead of high temperatures. It is also recommended to recycle the ABS to those who work with it; to use 5% of SEBS added to the recycled ABS to recover the possible loss of properties.