Reprocessing acrylonitrile–butadiene–styrene plastics: Structure–property relationships

Abstract

Acrylonitrile-butadiene-styrene (ABS) plastics from computer equipment housings have been reprocessed, some under various conditions of temperatures and shearing rates and others for multiple numbers of cycles. Structural changes in these reprocessed materials were investigated by infrared spectroscopy (FTIR), gel permeation chromatography, and dynamic mechanical thermal analysis. Gas chromatography/mass spectrometry was used to analyze extracts from the ABS plastics. These studies were related to measurements of the mechanical properties of the reprocessed materials, and the fracture surfaces were examined using scanning electron microscopy. It was found that impact strength was much more significantly affected than tensile properties by reprocessing. Within the range of reprocessing parameters studied, temperature had a more significant effect than shear rate on mechanical properties. Significant reductions in impact strength and slight increases in stiffness and strength, particularly following reprocessing at the highest temperature of 2708C and multiple reprocessing, were linked to loss of small molecules (including lubricants), degradation (crosslinking and scission) of the rubber phase, and changes in the morphology seen in the fracture surfaces. POLYM. ENG. SCI.,

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

“…A high level of stability in the ABS was observed after successive injection cycles; the tensile strength and elongation at break values remained virtually constant. This behavior has been observed by a number of other authors such as Bai et al (2007), Eguiazabal and Nazabal (1990), Perez et al (2010) and Salari and Ranjbar (2008). However, different impact strength values for the two temperatures (220 and 260 ºC) were obtained.…”

“…Its main advantage is the good relationship between price and performance, although the presence of a polybutadiene phase brings certain problems when it is submitted to various processing cycles, either by injection or extrusion. The studies carried out by Bai et al (2007), Boronat et al (2009), Karahaliou and Tarantili, (2009) and Perez et al (2010) clearly demonstrate this. Nearly all studies in this area highlight the crosslinking phenomena as the cause of the variation in properties that takes place (loss of ductility).…”

“…In the first case (220 ºC), impact energy remains more or less constant, but the values fall when the temperature used is 260 ºC. This phenomena was also observed by Bai et al (2007) and Eguiazabal and Nazabal (1990). This decrease is due to the crosslinking phenomenon arising from the break in C=C double bond, which limits the later use and application of the recycled ABS.…”

Recuperación De Plásticos Reciclados Mediante Adicción De Elastómeros Termoplásticos.

“…1c. En el primer caso (220ºC), la energía de impacto se mantiene prácticamente constante, pero los valores descienden cuando la temperatura de procesado es de 260ºC, [1,10]. Este descenso de resistencia al impacto es atribuido a un fenómeno de entrecruzamiento de cadenas por la rotura del doble enlace de C=C, lo cual limita el posterior uso y aplicación del ABS reciclado.…”

“…La principal ventaja es su buena relación entre precio y propiedades que presenta [2], aunque la presencia de una fase de polibutadieno conlleve ciertos problemas cuando es sometido a ciclos de procesado, bien sea por inyección o extrusión, [7][8][9][10]. Todos los estudios señalan al proceso de crosslinking como causante de la variación de propiedades (pérdida de resistencia al impacto).…”