Suchergebnisse

This research investigated the effect of Renolith chemical polymer additive (RCPA) on the properties of expanded polystyrene (ESP) concrete. Renolith chemical additive is a polymer-based product in a liquid form made up of latex and cellulose. Polystyrene panels were collected as a waste materials and grinded into smaller beads. An experimental investigation was carried out on the EPS replacement ranging from 0% to 100% on the M30 (C25/C30) mix design. Engineering properties, such as workability, density, water absorption, compressive strength, split tensile strength, and flexural strength tests, were studied for both the conventional and EPS concrete. The results indicate that workability increases with increasing amount of EPS contents. Water absorption, compressive, tensile, and flexural strength yielded a satisfactory result at 0-50% replacement. The density of the EPS concrete at 0-37.5% replacement revealed similar values to a conventional concrete; and light-weight concrete (1817.5 - 1030 kg⁄m3) was achieved at a 50-100% replacement. Generally, the addition of the RCPA to the concrete mix has caused an improvement in the properties of the EPS concrete. It was concluded that EPS beads can be used as a partial replacement for coarse aggregates in the production of both structural light-weight and dense concrete. The replacement of coarse aggregate with EPS beads showed a positive application as an alternative material for the construction industry.

The migration of benzophenone (BP), an antioxidant (2,6-di-tert-butyl-4-methyl-phenol (BHT)) and three plasticizers (diisobutyl phthalate (DiBP), bis(2-ethylhexyl) adipate (DEHA) and diisononyl phthalate (DiNP)) from different food contact materials into Tenax as food simulant was studied. The packaging materials analysed were: polyethylene (PE) and polyvinyl chloride (PVC) cling-films, paper bread bag, brown paper popcorn bag intended to be heated in a microwave oven and polypropylene (PP) coffee capsules. The analysis was carried out using PARAFAC and PARAFAC2 decompositions and gas chromatography/mass spectrometry (GC/MS), being DiBP-d4 the internal standard. Tenax has been used as food simulant for specific migration of dry foodstuffs according to Commission Regulation (EU) 10/2011. PARAFAC and PARAFAC2 decompositions enabled the unequivocal identification and quantification of all the analytes despite some of the m/z ratios of the coeluting interferents were shared with the analytes. Otherwise, the presence of the analytes could not have been ensured according to the EU legislation in force. BHT, DiBP and DEHA were contained in the Tenax blanks in some of the analyses. The amount of BP and DiBP migrated from the PVC film was 83.53 μg L−1 and 31.30 μg L−1, respectively; whereas 71.62 μg L−1 of BP and 27.45 μg L−1 of DiBP migrated from the PP coffee capsules. None of the analytes were detected above the capability of detection in the non-spiked migration samples of the rest of the food contact materials analysed. The efficiency of Tenax as an adequate food simulant has also been studied through the values of its adsorption capability which were different depending on the analytes and the materials. In the spiked migration samples, these values ranged from 25.33% to 99.37%. ; Spanish MINECO (AEI/FEDER, UE) through projects CTQ2014-53157-R and CTQ2017‐88894‐R and by Junta de Castilla y León through project BU012P17 (all co‐financed with European FEDER funds).

Polymer recycling is a way to reduce environmental impacts of accumulation of polymeric waste materials. However, low recycling rates are often observed in conventional centralized recycling plants mainly to the challenge of collection and transportation for high-volume low-weight-polymers in conventional centralized recycling plants. As the democratization of open-source 3D printers is going forward thanks to initiatives such as FabLab environments, there is a growing interest on how to use this technology to improve the efficiency of use of raw materials. Studies have been proposed in order to recycle waste polymer into open-source 3D printer feedstock. The recycling of high-density polyethylene (HDPE) issued from bottles of used milk jugs through use of an open-source filament fabricator system called RecycleBot has been evaluated. In this study, we propose an evaluation of the mechanical recyclability of Polylactic Acid (PLA), material widely used in the open-source 3D printing context, in order to establish the viability of this recycled material to be used in the open-source 3D printers. The degradation of the material's mechanical and rheological properties after a number of cycles of multiple extrusion and printing processes is evaluated. The characterization of recycled raw materials for open-source 3D printing has implications not only to reduce the environmental impact of polymers waste, but also it will allow us to understand the technical requirements and challenges for development of open-source filament recycle machine/process. The coupling of open-source 3D printers and filament extruders can offer the bases of a new distributed polymer recycling paradigm, which reverses the traditional paradigm of centralizing recycling of polymers where is often uneconomic and energy intensive due to transportation embodied energy. Moreover, this characterization also will allow the exploration of new source of materials and new composite materials for open-source 3D printing, in order to improve the quality of products made by this technology. ; Mechanical Engineering

International audience ; Polymer recycling is a way to reduce environmental impacts of accumulation of polymeric waste materials. However, low recycling rates are often observed in conventional centralized recycling plants mainly to the challenge of collection and transportation for high-volume low-weight-polymers in conventional centralized recycling plants. As the democratization of open-source 3D printers is going forward thanks to initiatives such as FabLab environments, there is a growing interest on how to use this technology to improve the efficiency of use of raw materials. Studies have been proposed in order to recycle waste polymer into open-source 3D printer feedstock. The recycling of high-density polyethylene (HDPE) issued from bottles of used milk jugs through use of an open-source filament fabricator system called RecycleBot has been evaluated. In this study, we propose an evaluation of the mechanical recyclability of Polylactic Acid (PLA), material widely used in the open-source 3D printing context, in order to establish the viability of this recycled material to be used in the open-source 3D printers. The degradation of the material's mechanical and rheological properties after a number of cycles of multiple extrusion and printing processes is evaluated. The characterization of recycled raw materials for open-source 3D printing has implications not only to reduce the environmental impact of polymers waste, but also it will allow us to understand the technical requirements and challenges for development of open-source filament recycle machine/process. The coupling of open-source 3D printers and filament extruders can offer the bases of a new distributed polymer recycling paradigm, which reverses the traditional paradigm of centralizing recycling of polymers where is often uneconomic and energy intensive due to transportation embodied energy. Moreover, this characterization also will allow the exploration of new source of materials and new composite materials for open-source 3D printing, in order ...

International audience ; Polymer recycling is a way to reduce environmental impacts of accumulation of polymeric waste materials. However, low recycling rates are often observed in conventional centralized recycling plants mainly to the challenge of collection and transportation for high-volume low-weight-polymers in conventional centralized recycling plants. As the democratization of open-source 3D printers is going forward thanks to initiatives such as FabLab environments, there is a growing interest on how to use this technology to improve the efficiency of use of raw materials. Studies have been proposed in order to recycle waste polymer into open-source 3D printer feedstock. The recycling of high-density polyethylene (HDPE) issued from bottles of used milk jugs through use of an open-source filament fabricator system called RecycleBot has been evaluated. In this study, we propose an evaluation of the mechanical recyclability of Polylactic Acid (PLA), material widely used in the open-source 3D printing context, in order to establish the viability of this recycled material to be used in the open-source 3D printers. The degradation of the material's mechanical and rheological properties after a number of cycles of multiple extrusion and printing processes is evaluated. The characterization of recycled raw materials for open-source 3D printing has implications not only to reduce the environmental impact of polymers waste, but also it will allow us to understand the technical requirements and challenges for development of open-source filament recycle machine/process. The coupling of open-source 3D printers and filament extruders can offer the bases of a new distributed polymer recycling paradigm, which reverses the traditional paradigm of centralizing recycling of polymers where is often uneconomic and energy intensive due to transportation embodied energy. Moreover, this characterization also will allow the exploration of new source of materials and new composite materials for open-source 3D printing, in order ...