Determining the composition of post-consumer flexible multilayer plastic packaging with near-infrared spectroscopy

Material flow analysis and recycling performance of an improved mechanical recycling process for post-consumer flexible plastics

“…The FTIR and DSC also have limitations in determining the composition of multilayer samples. FTIR can only detect the surface of flakes as the infrared beam does not penetrate more than 5 μm ( Roosen et al, 2021 , Chen et al, 2021 ). Flakes of one side PE and the other side PP are also assumed to be 50 % PP and 50 % PE, which is not necessarily the case.…”

NIR-MFCO dataset: Near-infrared-based false-color images of post-consumer plastics at different material flow compositions and material flow presentations

“…The used spectral range of the sensor was 990 nm to 1678 nm with a spectral resolution of 3.1 nm/band. The used NIR sensor has an on-chip classification engine, which is frequently used in different industrial and research applications [5 , [10] , [11] , [12] , [13] , [14] , [15] , [16] . The resulting spatial resolution of the NIR sensor is 1.08 mm/px and 3.50 mm/px for T1 and T2, respectively (cf.…”

Near-infrared-based determination of mass-based material flow compositions in mechanical recycling of post-consumer plastics: Technical feasibility enables novel applications

“…1b) (Kroell et al, 2022a). Since NIR is a surface measurement technology with a limited penetration depth (Chen et al, 2021b), only the composition of the material flow surface can be determined with NIR, which might differ from that of the full material flow (Kroell et al, 2022a). Thus, it is still unclear (a) if SBMC of post-consumer plastics in the case of missing material singling is technically feasible at all and (b) how accurate the obtained MFCOs are in such cases (Kroell et al, 2022a).…”

“…If a HDPE fray is on top of another HDPE flake, it is usually classified as HDPE, but if a HDPE fray overlays a PET flake, a mixed HDPE/PET spectra can occur due to the penetration depth of NIR (Chen et al, 2021b;Chen et al, 2023). Since mixed PET/HDPE spectra from transparent PET on top of HDPE are trained as "PET" to the classification model 4 (cf.…”