José Enrique Crespo Amorós

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.

Análisis de técnicas para abastecimiento de agua en la ingeniería hidráulica romana

En este trabajo se lleva a cabo una revision bibliografica sobre el uso de compatibilizantes basados en PE-g-MA, PP-g-MA y SEBS-g-MA. Se identifican las tres areas principales de trabajo: uso de compatibilizante en la mejora de las propiedades de la base compuesta, uso de compatibilizante en la mezcla de dos materiales, y el aspecto del compatibilizante como un componente mas en la mezcla de varios materiales, haciendo hincapie en la mejora de las propiedades del compuesto basico como la principal aplicacion y el uso de SEBS-g-MA como el compatibilizante mas utilizado en todos los casos.

ESTIMACIÓN DE LA ABSORCIÓN ACÚSTICA DE PANELES FABRICADOS CON NEUMÁTICOS RECICLADOS

ABSTRACT: The present study is conducted to characterize multilayer acoustic panels made from recycled tire rubbers (GTR’s) in order to determine the sound absorption characteristics of these new materials for different applications, trying to give an answer to the environmental problem generated by this waste. This waste is currently used as modifier of asphalt, sport surfaces, molded and calendered products. The article is a first step to evaluate the sound absorption of these new multilayer panels for application in fields such as noise barriers, noise of machinery and equipment, conditioning acoustic enclosures, etc.. Basically two types of products can be obtained from the waste of the tyres: fibers and rubbers. Two types of multilayer panels of thickness 10 mm and 20 mm have been made for a three layer disposition: rubber-fibre-rubber. Then, the standing wave tube method has been used to determine the sound absorption in these materials. For rubber there are 0,7 mm and 2,2-4 mm granulometry. The results show that multilayer panels made of 2,2-4 granulometry present a higher acoustic absorption in the studied frequency range (400-3500 Hz). By increasing the thickness of the panel, the sound absorption coefficient is higher and the multilayer panel increases its sound absorption by adding more percentage of rubber.

Mechanical and thermal properties analysis of polypropylene reinforced with polyamide microfibre obtained from shredded tyres

The importance of recovering waste materials generated by industrialised societies is mainly due to the environmental impact that they have, and one of the principal problems is the presence of end of life tyres. The use of waste microfibre obtained from shredded tyres as reinforcement in polypropylene matrices offers an interesting opportunity for recycling of the waste microfibre, in order to obtain ‘value added products’ from polypropylene (PP)/waste microfibre tyre composites. The microfibres obtained from shredded tyres were used as a reinforcing material in compositions with polypropylene (PP). The blending proportions were: (1) 10% microfibre 90% PP; (2) 20% microfibre, 80% PP; (3) 30% microfibre, 70% PP; (4) 40% microfibre, 60% PP, (5) 50% microfibre, 50% PP and (6) 80% microfibre, 20% PP. The mechanical and thermal properties were analyzed. In this case polypropylene mixed with polyamide (PA) microfibres show a decrease in tensile strength and elongation at break, however, impact strength and Vicat Softening temperature values increase with polyamide microfibre content. Continuity in the matrix phase was observed by scanning electron microscopy up to loadings of 40% microfibre.

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.