•Samples of waste, recycled and virgin plastics were obtained.•Majority of the samples contained phthalates.•Source of plastics significantly influenced the presence of phthalates.•Phthalates were ...not removed in recycling of household plastics.•DEHP could be used as indicator for monitoring phthalate contamination.
Plastics recycling has the potential to substitute virgin plastics partially as a source of raw materials in plastic product manufacturing. Plastic as a material may contain a variety of chemicals, some potentially hazardous. Phthalates, for instance, are a group of chemicals produced in large volumes and are commonly used as plasticisers in plastics manufacturing. Potential impacts on human health require restricted use in selected applications and a need for the closer monitoring of potential sources of human exposure. Although the presence of phthalates in a variety of plastics has been recognised, the influence of plastic recycling on phthalate content has been hypothesised but not well documented. In the present work we analysed selected phthalates (DMP, DEP, DPP, DiBP, DBP, BBzP, DEHP, DCHP and DnOP) in samples of waste plastics as well as recycled and virgin plastics. DBP, DiBP and DEHP had the highest frequency of detection in the samples analysed, with 360μg/g, 460μg/g and 2700μg/g as the maximum measured concentrations, respectively. Among other, statistical analysis of the analytical results suggested that phthalates were potentially added in the later stages of plastic product manufacturing (labelling, gluing, etc.) and were not removed following recycling of household waste plastics. Furthermore, DEHP was identified as a potential indicator for phthalate contamination of plastics. Close monitoring of plastics intended for phthalates-sensitive applications is recommended if recycled plastics are to be used as raw material in production.
•BFRs were analysed in plastics from household waste, virgin and recycled plastics.•Half (50%) of household waste plastics contained BFRs.•Concentrations up to 26,000,000ngTBBPA/g were measured in ...some recycled plastics.•Widespread presence of BFRs indicated unintended addition or chemical degradation.
Flame retardants are chemicals vital for reducing risks of fire and preventing human casualties and property losses. Due to the abundance, low cost and high performance of bromine, brominated flame retardants (BFRs) have had a significant share of the market for years. Physical stability on the other hand, has resulted in dispersion and accumulation of selected BFRs in the environment and receiving biota. A wide range of plastic products may contain BFRs. This affects the quality of waste plastics as secondary resource: material recycling may potentially reintroduce the BFRs into new plastic product cycles and lead to increased exposure levels, e.g. through use of plastic packaging materials. To provide quantitative and qualitative data on presence of BFRs in plastics, we analysed bromophenols (tetrabromobisphenol A (TBBPA), dibromophenols (2,4- and 2,6-DBP) and 2,4,6-tribromophenol (2,4,6-TBP)), hexabromocyclododecane stereoisomers (α-, β-, and γ-HBCD), as well as selected polybrominated diphenyl ethers (PBDEs) in samples of household waste plastics, virgin and recycled plastics. A considerable number of samples contained BFRs, with highest concentrations associated with acrylonitrile butadiene styrene (ABS, up to 26,000,000ngTBBPA/g) and polystyrene (PS, up to 330,000ng∑HBCD/g). Abundancy in low concentrations of some BFRs in plastic samples suggested either unintended addition in plastic products or degradation of higher molecular weight BFRs. The presence of currently restricted flame retardants (PBDEs and HBCD) identified in the plastic samples illustrates that circular material flows may be contaminated for extended periods. The screening clearly showed a need for improved documentation and monitoring of the presence of BFRs in plastic waste routed to recycling.
•Plastic from households contained higher metal concentrations than virgin plastic.•Reprocessed plastic from household waste had the highest metal concentrations.•PET plastic contained significantly ...more Sb than PE, PP and PS plastics.•“Dirt” has limited contribution to the presence of metals in waste plastics.•Higher recycling rates may lead to higher metal concentrations in recycled plastic.
The global consumption of plastic continues to increase, and plastic recycling is highlighted as crucial for saving fossil resources and closing material loops. Plastic can be made from different polymers and contains a variety of substances, added intentionally to enhance the plastic’s properties (metals added as fillers, colourants, etc.). Moreover, plastic can be contaminated during use and subsequent waste management. Consequently, if substances and contaminants are not removed during recycling, potentially problematic substances might be recycled with the targeted polymers, hence the need for quantitative data about the nature and presence of these substances in plastic. Samples of selected polymers (PET, PE, PP, PS) were collected from different origins; plastic household waste, flakes/pellets of reprocessed plastic from households and industry, and virgin plastic. Fifteen selected metals (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sb, Ti, Zn) were quantified and the statistical analysis showed that both the polymer and origin influenced the metal concentration. Sb and Zn were potentially related to the production stage of PET and PS, respectively. Household plastic samples (waste and reprocessed) were found to contain significantly higher Al, Pb, Ti and Zn concentrations when compared to virgin samples. Only the concentration of Mn was reduced during washing, suggesting that parts of it was present as physical contamination. While most of the metals were below legal limit values, elevated concentrations in reprocessed plastic from households, aligned with increasing recycling rates, may lead to higher metal concentrations in the future.
•All waste paper samples contained BPA, while BPS was found in 73% of them.•Except for BPS, use of BPA phenol-based analogues appeared to be limited.•Major flux of BPA and BPS in household waste ...paper came from four fractions.•The majority of thermal paper receipts contained either BPA or BPS.•BPA and its analogues could potentially persist in paper recycling.
Bisphenol A (BPA) is an industrial chemical produced in large volumes. Its main use is associated with polycarbonate plastic, epoxy resins and thermal paper. In contrast to other applications, thermal paper contains BPA in its un-reacted form as an additive, which is subjected to migration. Receiving a significant amount of attention from the scientific community and beyond, due to its controversial endocrine-disrupting effects, the industry is attempting to substitute BPA in variety of applications. Alternative phenolic compounds have been proposed for use in thermal paper; however, information to what extent BPA alternatives have been used in paper is sparse. The aim of the present work was to quantify BPA and its alternatives (bisphenol S (BPS), bisphenol E (BPE), bisphenol B (BPB), 4-cumylphenol (HPP) and bisphenol F (BPF)) in waste paper and board from Danish households, thermal paper receipts, non-carbon copy paper and conventional printer paper. BPA was found in all waste paper samples analysed, while BPS was identified in 73% of them. Only BPB was not identified in any of the samples. BPA and BPS were found in the majority of the receipts, which contained no measurable concentrations of the remaining alternatives. Although receipts showed the highest concentrations of BPA and BPS, office paper, flyers and corrugated boxes, together with receipts, represented the major flux of the two compounds in waste paper streams.
•Detailed fractional composition of Danish waste paper was presented.•Analyses included mineral oils, phthalates, phenols, PCBs, and toxic metals.•Large variations in chemical concentrations were ...found.•Paper from residual (mixed) waste showed higher chemical content.•Fate of chemicals in paper cycle should be assessed.
Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households, including both residual and source-segregated materials, which were disposed of (e.g., through incineration) and recycled, respectively. The concentration of selected chemicals was quantified for all of the samples. The quantified chemicals included mineral oil hydrocarbons, phthalates, phenols, polychlorinated biphenyls, and selected toxic metals (Cd, Co, Cr, Cu, Ni, and Pb). The results suggest large variations in the concentration of chemicals depending on the waste paper fraction analysed. Research on the fate of chemicals in waste recycling and potential problem mitigation measures should be focused on in further studies.
•Dataset of 74 physico-chemical properties for 49 residual and 24 source-segregated fractions.•Fractioning considered material recycling processes and function (i.e. packaging).•Significant ...differences in properties of fractions in residual and source-segregated waste.•Significant differences in properties of individual materials within fractions.•Rare earth elements were detected in all fractions with highest concentrations in ceramics.
Physico-chemical waste composition data are paramount for the assessment and planning of waste management systems. However, the applicability of data is limited by the regional, temporal and technical scope of waste characterisation studies. As Danish and European legislation aims for higher recycling rates evaluation of source-segregation and recycling chains gain importance. This paper provides a consistent up-to-date dataset for 74 physico-chemical parameters in 49 material fractions from residual and 24 material fractions from source-segregated Danish household waste. Significant differences in the physico-chemical properties of residual and source-segregated waste fractions were found for many parameters related to organic matter, but also for elements of environmental concern. Considerable differences in potentially toxic metal concentrations between the individual recyclable fractions within one material type were observed. This indicates that careful planning and performance evaluation of recycling schemes are important to ensure a high quality of collected recyclables. Rare earth elements (REE) were quantified in all waste fractions analysed, with the highest concentrations of REE found in fractions with high content of mineral raw materials, soil materials and dust. The observed REE concentrations represent the background concentration level in non-hazardous waste materials that may serve as a reference point for future investigations related to hazardous waste management. The detailed dataset provided here can be used for assessments of waste management solutions in Denmark and for the evaluation of the quality of recyclable materials in waste.
A huge challenge is to control the nucleation of crystallites/aggregates in the solution during polymer film formation to generate desired structures. In this work, we investigate crystallization of ...P(NDI2OD-T2), a donor–acceptor polymer semiconductor, with controlled solution flow along the contact line between the drying film and solution through a seesaw-like pivoting of samples during polymer drying. By controlling the pivoting frequency/amplitude, various types of line patterns can be observed: (I) an array of fishbone-like stripes oriented in the film-growth direction; (II) the pinning–depinning of contact line (PDCL)-mechanism-defined patterned wires along the contact line; and (III) periodic twined crystalline line pattern oriented in the direction of the contact line. The rich variety of pattern formation observed is attributed to the distinctiveness of the donor–acceptor conjugated polymer structure. The result measured from thin-film transistors made of the generated films/structures showed that the charge mobility of P(NDI2OD-T2) does not change much with the film morphology, which supports recent controversy over the charge-transportation mechanism of some donor–acceptor polymer semiconductors.
In this paper, an electrical performance verification methodology for large reflector antennas is proposed. The verification methodology was developed for the BIOMASS P-band (435 MHz) synthetic ...aperture radar (SAR), but can be applied to other large deployable or fixed reflector antennas for which the verification of the entire antenna or payload is impossible. The two-step methodology is based on accurate measurement of the feed structure characteristics, such as complex radiation pattern and radiation efficiency, with an appropriate measurement technique, and then accurate calculation of the radiation pattern and gain of the entire antenna including support and satellite structure with an appropriate computational software. A preliminary investigation of the proposed methodology was carried out by performing extensive simulations of different verification approaches. The experimental validation of the methodology included measurements of the prototype BIOMASS feed in several structural configurations with spherical, cylindrical, and planar near-field techniques. The measured characteristics for the feed structure were then used in the calculation of the radiation pattern and gain of the entire reflector antenna. The main emphasis of the work was on the assessment of the achievable pattern and gain uncertainty for the entire antenna and its compliance with the BIOMASS SAR requirements.
Diagnostics of the BIOMASS feed array prototype Cappellin, C.; Pivnenko, S.; Pontoppidan, K. ...
2013 7th European Conference on Antennas and Propagation (EuCAP),
2013-April
Conference Proceeding
The 3D reconstruction algorithm is applied to the prototype feed array of the BIOMASS synthetic aperture radar, recently measured at the DTU-ESA Spherical Near-Field Antenna Test Facility in Denmark. ...Careful analysis of the measured feed array data has shown that the test support structure of the array has a dominant influence on the measured feed pattern. The 3D reconstruction is then applied to the feed array measured data, allowing the identification of the undesired currents induced on the feed support structure. The results of the diagnostics and the corresponding improvements of the feed pattern obtained by removal of the undesired currents are presented and discussed.
In this paper, possible verification strategies for large deployable reflector antennas are reviewed and analysed. One of the approaches considered to be the most feasible and promising is based on ...measurements of the feed characteristics, such as pattern and gain, and then calculation of the overall reflector antenna pattern and gain. The approach is further investigated by computer simulations. A reference result is obtained by simulation of the entire antenna using the Method of Moments. The measurements of the feed are then simulated in several configurations, including the feed alone and parts of the spacecraft. The secondary pattern of the reflector is then calculated and compared to the reference.
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