This article provides a review of the research unde rt aken in order to determine the suitability of utilizing microwave technology in the production of Recycled ABS Acrylonitrile Butadiene Styrene resin for mouldin g...This article provides a review of the research unde rt aken in order to determine the suitability of utilizing microwave technology in the production of Recycled ABS Acrylonitrile Butadiene Styrene resin for mouldin gs. The experimental investigation determined the suitability of the existing re cycled ABS material, the mould material used with respect to performance and lon gevity, potential commercial plant and equipment, end mould compression. Introduction Frequency Characterization of ABS The first step in microwave processing of any material is to locate a frequency band suitable for the mateiial, where it absorbs microwave energy readily. To lo cate this band width, the ABS material was characterized in Variable Frequency M icrowave Ovens operating between the frequenc’y ranges of 2.5 GHz to 6.5 GHz an d 6 GHz to 18 GHz. The variable frequency microwave oven records forward and ref lected powers over regular intervals in the swept frequency range and enables ca lculation of Re flec tan ce=Re fla tan ce forwrd PowerForward Power (1) A low reflectance indicates that the material Forward Power absorbs rela tively higher amount of incident microwave energy. Characterization of the PBS material showed clearly that a frequancy Fig.1 Lower frequency range vs. reflectance of ABS at room te mperatureFig.2 Lower frequency range vs. reflectance of AB S at 80 ℃ 2.5 to 3.5 GHz is the most suitable frequency fo r heating the material. Other alternate frequencies are 12.25 GHz and 15 GHz. Fi g.1. Hazards When ABS is melted a dark fume is omitted, exhaust system was applied, in order to mechanically ventilate and control exposure levels below air borne exposures. The product contains a trace quantity of acrylonitrile, a substance classified by Worksafe Australia as a Category 2 Carcinogen. [TPP115B,+28mm95mm,Y,PZ#] Fig.3 Polypropylene mouldMould design For holding the ABS granules in a single mode cavity, an unfilled p olypropylene mould was designed. A polypropylene lid with a loading arrangement built in the microwave cavity provided pressure to the materinl in the die, duri ng microwave heating. The pressure can be varied with changing weights on the lo ading device and calculating the pressure. Materials Polypropylene has excellent microwave heating properties, a mould was machine to cater for the experimental requirements. Other materials suitable for mould des ign for long term use are quartz and alumina. Quartz being transparent to both m icrowaves and light provides advantages in noncontact optical temperature measur ements. Conclusion The application of microwave heating for the manufacturing of ABS die casts stru ctures has been developed. An experimental results based on the dielectric behav iour illustrate dopent is required to engage dielectric heating. Chemical Compos ition of ABS, Acrylonitrile Butadiene Styrene, the percentage of each compound a s it would have a direct relationship on the dielectric properties of the ABS.展开更多
Modem societies strongly support the recycling practices over simple waste accumulation due to environmental harm caused. In the framework of sustainable recycling of plastics from WEEE, pyrolysis is proposed here as ...Modem societies strongly support the recycling practices over simple waste accumulation due to environmental harm caused. In the framework of sustainable recycling of plastics from WEEE, pyrolysis is proposed here as a means of obtaining secondary value-added products. The aim of this study was to investigate the thermal degradation and the products obtained after pyrolysis of specific polymers found in the plastic part of WEEE, using thermogravimetric analysis and a pyrolizer equipped with a GC/MS. Polymers studied include ABS, HIPS, PC and a blend having a composition similar to that appearing in WEEE. It was found that, PC shows greater heat endurance compared to the other polymers, whereas ABS depolymerizes in three-steps. The existence of several polymers in the blend results in synergistic effects which decrease the onset and final temperature of degradation. Moreover, the fragmentation occurred in the pyrolyzer, at certain temperatures, resulted in a great variety of compounds, depending on the polymer type, such as monomers, aromatic products, pnenoJlc compounds and hydrocarbons. The main conclusion from this investigation is that pyrolysis could be an effective method for the sustainable recycling of the plastic part of WEEE resulting in a mixture of chemicals with varying composition but being excellent to be used as fuel retrieved from secondary recycling sources.展开更多
文摘This article provides a review of the research unde rt aken in order to determine the suitability of utilizing microwave technology in the production of Recycled ABS Acrylonitrile Butadiene Styrene resin for mouldin gs. The experimental investigation determined the suitability of the existing re cycled ABS material, the mould material used with respect to performance and lon gevity, potential commercial plant and equipment, end mould compression. Introduction Frequency Characterization of ABS The first step in microwave processing of any material is to locate a frequency band suitable for the mateiial, where it absorbs microwave energy readily. To lo cate this band width, the ABS material was characterized in Variable Frequency M icrowave Ovens operating between the frequenc’y ranges of 2.5 GHz to 6.5 GHz an d 6 GHz to 18 GHz. The variable frequency microwave oven records forward and ref lected powers over regular intervals in the swept frequency range and enables ca lculation of Re flec tan ce=Re fla tan ce forwrd PowerForward Power (1) A low reflectance indicates that the material Forward Power absorbs rela tively higher amount of incident microwave energy. Characterization of the PBS material showed clearly that a frequancy Fig.1 Lower frequency range vs. reflectance of ABS at room te mperatureFig.2 Lower frequency range vs. reflectance of AB S at 80 ℃ 2.5 to 3.5 GHz is the most suitable frequency fo r heating the material. Other alternate frequencies are 12.25 GHz and 15 GHz. Fi g.1. Hazards When ABS is melted a dark fume is omitted, exhaust system was applied, in order to mechanically ventilate and control exposure levels below air borne exposures. The product contains a trace quantity of acrylonitrile, a substance classified by Worksafe Australia as a Category 2 Carcinogen. [TPP115B,+28mm95mm,Y,PZ#] Fig.3 Polypropylene mouldMould design For holding the ABS granules in a single mode cavity, an unfilled p olypropylene mould was designed. A polypropylene lid with a loading arrangement built in the microwave cavity provided pressure to the materinl in the die, duri ng microwave heating. The pressure can be varied with changing weights on the lo ading device and calculating the pressure. Materials Polypropylene has excellent microwave heating properties, a mould was machine to cater for the experimental requirements. Other materials suitable for mould des ign for long term use are quartz and alumina. Quartz being transparent to both m icrowaves and light provides advantages in noncontact optical temperature measur ements. Conclusion The application of microwave heating for the manufacturing of ABS die casts stru ctures has been developed. An experimental results based on the dielectric behav iour illustrate dopent is required to engage dielectric heating. Chemical Compos ition of ABS, Acrylonitrile Butadiene Styrene, the percentage of each compound a s it would have a direct relationship on the dielectric properties of the ABS.
文摘Modem societies strongly support the recycling practices over simple waste accumulation due to environmental harm caused. In the framework of sustainable recycling of plastics from WEEE, pyrolysis is proposed here as a means of obtaining secondary value-added products. The aim of this study was to investigate the thermal degradation and the products obtained after pyrolysis of specific polymers found in the plastic part of WEEE, using thermogravimetric analysis and a pyrolizer equipped with a GC/MS. Polymers studied include ABS, HIPS, PC and a blend having a composition similar to that appearing in WEEE. It was found that, PC shows greater heat endurance compared to the other polymers, whereas ABS depolymerizes in three-steps. The existence of several polymers in the blend results in synergistic effects which decrease the onset and final temperature of degradation. Moreover, the fragmentation occurred in the pyrolyzer, at certain temperatures, resulted in a great variety of compounds, depending on the polymer type, such as monomers, aromatic products, pnenoJlc compounds and hydrocarbons. The main conclusion from this investigation is that pyrolysis could be an effective method for the sustainable recycling of the plastic part of WEEE resulting in a mixture of chemicals with varying composition but being excellent to be used as fuel retrieved from secondary recycling sources.
