Elaboration and Characterization of Traced Polypropylene with Rare Earth Oxides for Automatic Identification and Sorting of End-of-Life Plastics

Abstract

The rare earth oxides can be used as tracers forthe identification of polymer materials. This study focusedon the detection of these particles and their effects on themechanical and thermal properties of polypropylene (PP).A new method was carried out to increase the sortingselectivity of PP during end of life recycling process and toimprove the efficiency of sorting and its high speed identification.The tests were realized in a test system devicewhich allows the collection of static measurements of thesamples spectrum through the use of energy dispersiveX-ray fluorescence technology. Five of the seven tracerstested are clearly visible and distinguishable from thebackground sample by their Ka1 energy line at concentrationlevels of 0.1 and 0.145 wt%. For the two remainingtracers, their Ka1 energy lines come out at the same domainof energy as the source. Dispersion of rare earth oxides at0.1 and 1 wt% do not have a significant impact on thecrystallization and melting temperature as well as on thetemperature of maximum decomposition rate. The additionof 1 wt% of rare earth oxides leads to a slight increase ofthe flexural modulus, whereas the addition of 0.1 and 1wt% causes a decrease of the elongation at break. SEMimages show a homogenous dispersion of tracers in the PPmatrix.International audienceAbstract The rare earth oxides can be used as tracers forthe identification of polymer materials. This study focusedon the detection of these particles and their effects on themechanical and thermal properties of polypropylene (PP).A new method was carried out to increase the sortingselectivity of PP during end of life recycling process and toimprove the efficiency of sorting and its high speed identification.The tests were realized in a test system devicewhich allows the collection of static measurements of thesamples spectrum through the use of energy dispersiveX-ray fluorescence technology. Five of the seven tracerstested are clearly visible and distinguishable from thebackground sample by their Ka1 energy line at concentrationlevels of 0.1 and 0.145 wt%. For the two remainingtracers, their Ka1 energy lines come out at the same domainof energy as the source. Dispersion of rare earth oxides at0.1 and 1 wt% do not have a significant impact on thecrystallization and melting temperature as well as on thetemperature of maximum decomposition rate. The additionof 1 wt% of rare earth oxides leads to a slight increase ofthe flexural modulus, whereas the addition of 0.1 and 1wt% causes a decrease of the elongation at break. SEMimages show a homogenous dispersion of tracers in the PPmatrix

A study on the dispersion, preparation, characterization and photo-degradation of polypropylene traced with rare earth oxides

“…In previous work [2], it has been shown that the addition of 1 wt % of Nd 2 O 3 and Gd 2 O 3 leads to a slight increase of the Young's modulus and a slight decrease of the yield stress. Regarding the tensile tests, the most important effect of these rare earth oxides was observed on the elongation at break.…”

“…Tracers consist of systems formed by one or several substances dispersed into a material with the aim of adding a selective property to it and improving its identification. In recent works [1,2], an X-ray fluorescence (XRF) detection system based on the use of tracers for the identification of polymer materials was reported by the authors. This system was developed with the objective of having an economical, efficient and automatic sorting of plastic wastes.…”

“…Following the above mentioned previous works [1,2], which report the possibility of detecting rare earth oxides through the use of XRF, our study presents a complementary approach with a research on the dispersion, elaboration, characterization and photo-degradation of traced polypropylene with rare earth oxides. The main objectives of this study are first, to quantitatively characterize the dispersion of tracers in the PP matrix which is of prime importance for their detection and for the mechanical properties of the traced PP.…”

High shear dispersion of tracers in polyolefins for improving their detection

“…Bezati et al [11][12][13][14] have shown that the X-ray fluorescence allows the detection of few tracers, while the magnetic detection is applied for the detection of only one tracer. Furthermore, the X-ray fluorescence detection which is a volume detection, can be a reliable method for high speed identification and sorting of black plastics into different families and grades.…”

Hybrid Inorganic–Organic Luminescent Supraparticle Taggants with Switchable Dual‐Level ID

“…[ 1 ] In particular, the use of identification (ID) taggants as smart additives could enable automatic identification, tracking, and tracing of materials, thus aiding the implementation of sustainable concepts, such as Circular Economy. [ 2–6 ] Additionally, developments in the digitalization of manufacturing could be fostered by the realization of the Internet of Things, thanks to programmable ID taggants. [ 7–9 ] Moreover, ID taggants could contribute to the establishment of transparent global trading networks and prevent product counterfeiting, thereby improving quality assurance.…”