The amount of plastic products as well as the amount of plastic waste increases every year. For many years, international studies on sensor-supported sorting are trying to find a solution to improve the quality of waste classification, so that plastics are correctly sorted before the actual recycling process begins. Binder+Co has developed a measuring device for laser-induced luminescence of solids, which has been tested in this work for the detection of plastics. For this research plastics with known composition, so-called reference plastics, are required. The unknown plastics were identified by using two gadgets, a FTIR- and a NIR-spectrometer. Subsequently, the plastics were labeled and sorted into different categories. The properties and the test results of the different plastic categories were stored in a plastic library which was especially established for this work. The research with the help of the laser-induced luminescence method revealed differences in the emitted signal intensities and the emitted color signals. These differences can mainly be attributed to the visually recognizable colors of the plastics. Types of plastic have different UV-light-persistence, therefore, their polymer structure and thus the emitted color signals change when exposed to UV-light. This process is called the aging of plastics. Analyses show that the process of aging significantly influences the signals received from the luminescence of the plastics. This leads to a high complexity in the recognition of recycling plastics through the laser-induced luminescence method, due to a lack of information about the content of additives and the progress of the aging process. In summary it is to say that the use of the laser-induced luminescence method is a suboptimal solution for the sorting of commercially available mixed plastic fractions. On the contrary the said method can strongly be recommended for the sorting of an homogenous plastic fraction such as PET.
|Translated title of the contribution
|Luminescence analysis of recycled plastics in view of utilization in the sensor-supported sorting
|21 Oct 2016
|Published - 2016
Bibliographical noteembargoed until 25-08-2019
- laser spectroscopy