THz imaging for recycling of black plastics

Kuter, Andries; Reible, Stefan; Geibig, Thomas; Nüßler, Dirk; Pohl, Nils

doi:10.1515/teme-2017-0062

Cited by 25 publications

(14 citation statements)

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“…Conversely, some applications on polymers are related to the evaluation of joints in plastics ( Koch and Krok, n.d .). Furthermore, since some black plastics used in the motor vehicle industry cannot be sorted using conventional optical sorting systems, THz technology can help in identifying different polymeric resins as well as black plastics ( Küter et al, 2018 ). Another application is related to the monitoring of composites and identifying fillers in polymers such as in PP ( Menlosystems, 2015 ).…”

Section: Current Photonic Techniques Applied For Monitoring Of Plasticsmentioning

confidence: 99%

Review on the photonic techniques suitable for automatic monitoring of the composition of multi-materials wastes in view of their posterior recycling

et al. 2021

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In the increasingly pressing context of improving recycling, optical technologies present a broad potential to support the adequate sorting of plastics. Nevertheless, the commercially available solutions (for example, employing near-infrared spectroscopy) generally focus on identifying mono-materials of a few selected types which currently have a market-interest as secondary materials. Current progress in photonic sciences together with advanced data analysis, such as artificial intelligence, enable bridging practical challenges previously not feasible, for example in terms of classifying more complex materials. In the present paper, the different techniques are initially reviewed based on their main characteristics. Then, based on academic literature, their suitability for monitoring the composition of multi-materials, such as different types of multi-layered packaging and fibre-reinforced polymer composites as well as black plastics used in the motor vehicle industry, is discussed. Finally, some commercial systems with applications in those sectors are also presented. This review mainly focuses on the materials identification step (taking place after waste collection and before sorting and reprocessing) but in outlook, further insights on sorting are given as well as future prospects which can contribute to increasing the circularity of the plastic composites’ value chains.

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Section: Current Photonic Techniques Applied For Monitoring Of Plasticsmentioning

confidence: 99%

Review on the photonic techniques suitable for automatic monitoring of the composition of multi-materials wastes in view of their posterior recycling

et al. 2021

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“…Yet, sorting is mandatory to achieve interesting properties since most polymers are said incompatible, leading to immiscibility and poor mechanical properties [ 11 , 16 , 17 ]. However, several technologies are currently in development, such as MIR-HSI [ 18 , 19 , 20 ], Terahertz spectroscopy [ 21 , 22 ] or LIBS [ 23 , 24 , 25 ], which could then enable profitable recycling of WEEP.…”

Section: Introductionmentioning

confidence: 99%

Degradation of Styrenic Plastics during Recycling: Accommodation of PP within ABS after WEEE Plastics Imperfect Sorting

Signoret¹,

Girard²,

Guen³

et al. 2021

Polymers

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With the development of dark polymers for industrial sorting technologies, economically profitable recycling of plastics from Waste Electrical and Electronical Equipment (WEEE) can be envisaged even in the presence of residual impurities. In ABS extracted from WEEE, PP is expected to be the more detrimental because of its important lack of compatibility. Hence, PP was incorporated to ABS at different rates (2 to 8 wt%) with a twin-screw extruder. PP was shown to exhibit a nodular morphology with an average diameter around 1–2 µm. Tensile properties were importantly diminished beyond 4 wt% but impact resistance was decreased even at 2 wt%. Both properties were strongly reduced as function of the contamination rate. Various potential compatibilizers for the ABS + 4 wt% PP system were evaluated: PPH-g-MA, PPC-g-MA, ABS-g-MA, TPE-g-MA, SEBS and PP-g-SAN. SEBS was found the most promising, leading to diminution of nodule sizes and also acting as an impact modifier. Finally, a Design Of Experiments using the Response Surface Methodology (DOE-RSM) was applied to visualize the impacts and interactions of extrusion temperature and screw speed on impact resistance of compatibilized and uncompatibilized ABS + 4 wt% PP systems. Resilience improvements were obtained for the uncompatibilized system and interactions between extrusion parameters and compatibilizers were noticed.

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“…However, polymers tainted in mass with carbon black become invisible to near-infrared hyperspectral imagery (NIR-HSI), the currently most used technology with sink-float for industrial sorting [13,14], mandatory to obtain satisfactory properties through mechanical recycling [15,16]. Development of new technologies to overcome this dark plastics sorting issue is currently subject to tremendous research [17][18][19][20][21][22][23][24] and could enable proper recycling of sorted WEEP. Study of styrenics recyclability, especially after ageing, is thus a hot topic.…”

Section: Introductionmentioning

confidence: 99%

Degradation of Styrenic Plastics During Recycling: Impact of Reprocessing Photodegraded Material on Aspect and Mechanical Properties

Signoret¹,

Edo²,

Lafon³

et al. 2020

J Polym Environ

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The major technical limitations in polymer recycling are their incompatibility between each other and their ageing. In this study, impact reinforced styrenics, namely HIPS and ABS, were evaluated in the scope of their alterations through recycling photooxidized material. In this purpose, plates were photodegraded in both natural and accelerated conditions. FTIR-ATR was used to monitor their ageing. After the desired ageing durations, plates were ground, extruded and injected into ISO1 dumbbell tensile test specimens to simulate recycling of degraded polymers. Strong interactions were observed between photooxidation and polymer processing through photometry measures, associated color changes, tensile and impact properties. It was noticed that unaged materials displayed only moderated alterations through recycling. Because of their close chemistry, HIPS and ABS share several modifications but ABS was less altered and mainly impact properties were affected. HIPS and ABS difference of sensibilities could be rooted in PB phases different morphologies and grafting between the two materials.

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THz imaging for recycling of black plastics

Cited by 25 publications

References 0 publications

Review on the photonic techniques suitable for automatic monitoring of the composition of multi-materials wastes in view of their posterior recycling

Review on the photonic techniques suitable for automatic monitoring of the composition of multi-materials wastes in view of their posterior recycling

Degradation of Styrenic Plastics during Recycling: Accommodation of PP within ABS after WEEE Plastics Imperfect Sorting

Degradation of Styrenic Plastics During Recycling: Impact of Reprocessing Photodegraded Material on Aspect and Mechanical Properties

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