Recycling of ABS and PC from electrical and electronic waste. Effect of miscibility and previous degradation on final performance of industrial blends (original) (raw)
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Processing and Characterization of Recycled PC/Abs Blends With High Recycle Content
In order to develop a polycarbonate (PC)/ acrylonitrile-butadiene-styrene (ABS) product with a high content of recycled PC, a low molecular weight virgin PC was added to recycled PC to minimize batch-to-batch property variations in the compounded product. Six PC/ABS blends were prepared on a twin screw extruder by mixing 50 wt% virgin ABS and 0-25 wt% low molecular weight virgin PC with 25-50 wt% high purity recycled PC recovered from end-of-life electronics. These blends were characterized rheologically and mechanically. Results showed that this strategy could yield consistent quality resin blends with a high recycle content.
Journal of Applied Polymer Science, 2017
In the challenging prospect of developing new materials by mixing different polymers to reach a synergetic performance, the present research focuses on the study of the miscibility of two polymers: The acrylonitrile butadiene styrene (ABS) composed of a dispersed elastomeric (polybutadiene rubber) polymer embedded in a SAN thermoplastic matrix, and the polycarbonate (PC). It shall be noted that obtaining miscible polymer blends is often a difficult task because of the large size of their molecular chains and the high interfacial tension between the polymer phases. Until now, the most numerous researches developed in this field involve polymer blends obtained by compatibilization techniques in order to improve the interfacial adhesion between initial polymers. The aim of this work is to study the miscibility between ABS and PC. First, two different methods were used to mix the polymers: the twinscrew extrusion and the dissolution in a common solvent tetrahydrofuran (THF). Then, physicochemical, microscopic observation and rheological characterization were performed on samples of mixtures obtained by both extrusion processing and dissolution method. The measurement of glassy transition temperature (T g) by differential scanning calorimetry measurements (DSC) and dynamical mechanical thermal analysis (DMTA) have shown a partial miscibility between the two polymers
Study of thermal degradation behavior and kinetics of ABS/PC blend
Polish Journal of Chemical Technology, 2020
This work investigated kinetics and thermal degradation of acrylonitrile butadiene styrene and polycarbonate (ABS/PC) blend using thermogravimetric analysis in the range of 25 to 520°C. For thermal degradation of blend, activation energy (E a ) and pre-exponential factor (A) were calculated under various heating rates as 5, 10, 15 and 20°C/min using iso-conversional model-free methods (Kissinger, Flynn-Wall- Ozawa and Friedman). Mass loss of the blend as a function of temperature was plotted as thermogravimetric curve (TG) while derivative values of mass loss were drawn as derivative thermogravimetric (DTG) curve. Using Kissinger method, E a was 51.4 kJ/mol, while values calculated from FWO and Friedman method were 86–161 and 30–251 kJ/mol respectively. Results showed increasing trend of E a with higher conversion values indicating different degradation mechanisms at the initial and final stages of the experiment. Thermodynamic parameters such as enthalpy change (ΔH), Gibbs free ene...
A Degradation Study of Virgin and Recycled ABS Blends Subjected to Multiple Processing
International Journal of Research in Mechanical Engineering
The reprocessing ability of virgin and recycled acrylonitrile–butadiene– styrene (ABS) blends has been investigated to examine the recycling feasibility in industrial production. Up to 60 reprocessing cycles have been performed by injection moulding, and the effects on tensile and rheological properties have been studied. In order to prolong the reprocessing operation, recycled ABS was added to virgin ABS plastic, creating a 20% recycled blend in volume percentage, to minimize batch-to-batch property variations in the product. A recurrence formula has been developed to determine the composition of recycled plastic at different reprocessing cycles. The properties of the ABS blends were characterized in terms of mechanical, rheological and morphological perspective. More specifically, the tensile properties of the aforementioned blends were investigated in terms of the influence of the recyclate on the functional performance of the product via tensile tests using the split-disc method. Furthermore, the rheological properties of the blends were studied via melt flow index (MFI) tests, to assess their process ability during melt mixing and moulding processes. The stress whitening areas of the tensile fracture surface were examined by using the scanning electron microscopy (SEM). Results revealed that reprocessing ability of virgin and recycled ABS blends could yield satisfactory quality as attractive as that corresponding to the virgin ABS product. The virgin and recycled ABS blend resulted in 10% variation in tensile and rheological properties during multiple processing. This effort might be a contribution to convince the industry to apply recycling of ABS by means of multiple reprocessing, which includes blending technique in their long production runs.
Some Mechanical and Thermal Properties of PC/ABS Blends
Materials Sciences and Applications, 2011
A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) were prepared and some of their thermal and mechanical properties were determined. The Young's modulus changed gradually and monotonically with the polycarbonate content. This effect was tentatively explained as the antiplasticization of the PC which is ascribed to the chain mobility, which permits the PC chains to pack more tightly, to the secondary cross-linking between the PC chains, or to the secondary attachment of bulky side-chains to the PC, thus producing steric hindrance to the rotation of the PC main chains. The experimental values found for the impact strength were intermediate between those of the neat polymers, depending upon the dispersed rubber particles of butadiene in the matrix of SAN (Styrene-Acrylonitrile), and the dispersed PC particles which generally make the ABS more brittle. A maximum value of about 88 KJ/m 2 for the impact strength was observed for the blend with 90% PC. This may be attributed to the strong polymer-polymer interactions for this particular composition. The variations in the heat deflection temperature HDT and the Vicat softening point with the blend composition were very similar, and allowed us to assume that the phase inversion between the matrices of the two polymers takes place at 50% PC. The morphology of the blends revealed by SEM observation, show a co-continuous structure.
Rheological and mechanical properties of ABS/PC blends
2005
Acrylonitrile-Butadiene-Styrene (ABS), polycarbonate (PC) and their alloys are an important class of engineering thermoplastics that are widely used for automotive industry, computer and equipment housings. For the process of recycling mixtures of ABS and PC, it is desirable to know how sensitive the blend properties are to changes in compositions. It was for this reason that blends of virgin ABS and virgin PC at five different compositions, namely, and by weight of ABS were prepared and characterised by rheological and mechanical measurements. Rheological properties of these blends in steady, oscillatory and transient step shear and mechanical properties, namely, tensile strength, elongation-at-break and Izod impact strength are reported. The results show that PC behaves in a relatively Newtonian manner, but ABS exhibits significant shear thinning. The ABS-rich blends show a trend that is similar to that of ABS, while PC-rich blends, namely and , exhibit a nearly Newtonian behaviou...
Thermo-mechanical variability of post-industrial and post-consumer recyclate PC-ABS
Polymer Testing
The aim of this work is to investigate the performance variability of post-industrial (PIR) and post-consumer recycled (PCR) polycarbonate acrylonitrile-butadiene-styrene (PC-ABS). In addition, necessary testing methodology for understanding polymer variation in recycled polymers are established. The thermal expansion behaviour of all tested material were found to be similar and FT-IR testing revealed no conclusive evidence of oxidative degradation. Both PIR and PCR exhibited similar levels of variation in mechanical properties compared with prime samples, with the exception of elongation at break and quasi-static impact behaviour. In these two tests, prime polymers showed lower variation and superior performance to both recycled polymers. The presence of defects and changes in molecular weight were determined to be leading causes of the reduced deformability. Our work contributes by identifying key areas where recycled PC-ABS show good potential as replacements for neat PC-ABS. Furthermore, the work demonstrates methods for material testing against performance criteria to pave way for effective replacement of neat PC-ABS with its recycled counterparts.
Materials, 2016
Morphology formation during compounding, as well as injection molding of blends containing 60 wt % polycarbonate (PC) and 40 wt % polybutadiene rubber-modified styrene-acrylonitrile copolymers (ABS), has been investigated by transmission electron microscopy (TEM). Profiles of the blend morphology have been recorded in injection-molded specimens and significant morphology gradients observed between their skin and core. A <10 µm thick surface layer with strongly dispersed and elongated nano-scale (streak-like) styrene acrylonitrile (SAN) phases and well-dispersed, isolated SAN-grafted polybutadiene rubber particles is followed by a 50-150 µm thick skin layer in which polymer morphology is characterized by lamellar SAN/ABS phases. Thickness of these lamellae increases with the distance from the specimen's surface. In the core of the specimens the SAN-grafted polybutadiene rubber particles are exclusively present within the SAN phases, which exhibit a much coarser and less oriented, dispersed morphology compared to the skin. The effects of the viscosity of the SAN in the PC/ABS blends on phase morphologies and correlations with fracture mechanics in tensile and impact tests were investigated, including scanning electron microscopy (SEM) assessment of the fracture surfaces. A model explaining the mechanisms of morphology formation during injection molding of PC/ABS blends is discussed.
Thermomechanical properties of ABS/PA and ABS/PC blends
International Journal of Material Forming, 2009
The significant increase of Waste Electric and Electronic Equipment (WEEE) has led to an important research in upgrading recycled engineering plastics by means of a blending technique. Classical twin-screw extrusion is compared to a new blending technique, where two polymers are combined together and then flow in several static mixers. This technique allows to obtain different morphologies of compatibilized ABS/PA or ABS/PC blends and the aim of this work is to evaluate the corresponding thermomechanical properties. Experimental results demonstrate in particular that fibrilar morphology is obtained with the new blending technique (only with ABS/PA blends), which could lead to a mechanical enhancement if the adhesion between ABS and PA is optimized.