The influence of processing on the mechanical properties and emissions of recycled polyolefin

Thomas Höftberger, Christoph Burgstaller

Research output: Chapter in Book/Report/Conference proceedingsConference contributionpeer-review

Abstract

Some recycled plastics would provide the mechanical, thermal, and optical properties to replace virgin materials in some applications, but they are not used because of their odor. The reason for the unpleasant odour of post-consumer recyclates is that they are containing volatile compounds from their former applications, which also may have undergone degradation in the recycling steps, like residues from food or drinks which were stored in the package. We found that a reduction of such emissions is possible in the melt processing step of the recycling in a previous work but saw a big influence of processing parameters as the material will also further degrade in this step [1]. Therefore, the aim of this work was to investigate the reduction of the emissions in a co-rotating twin screw extruder with vacuum degassing, with an emphasis on different temperature profiles and screw configurations. Previous tests have shown that the temperature is a major factor to reduce the emissions, but around 250°C degradation effects have a negative influence. Therefore, another test series was processed to validate this effect and to find the optimal temperature settings for the process. The untreated recyclate was processed with different screw configurations. The emissions of all the compounds were determined with gas chromatography according to VDA 277. Further, mechanical characterization with tensile and notched impact tests was carried out to investigate the effects of the different processing parameters on the materials behavior. In addition, also the Oxidation Induction Time was determined to check how much of the stabilizer is left in the material. The results were compared to find the best settings for the process. The first tests with different screws show that emissions can be reduced over 70% with the right screw configuration and process settings.

Original languageEnglish
Title of host publicationProceedings of the 36th International Conference of the Polymer Processing Society, PPS 2021
EditorsAbdellah Ajji, Frej Mighri, Hani E. Naguib
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735445062
DOIs
Publication statusPublished - 23 May 2023
Event36th International Conference of the Polymer Processing Society, PPS 2021 - Montreal, Canada
Duration: 26 Sept 202129 Sept 2021

Publication series

NameAIP Conference Proceedings
Volume2607
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference36th International Conference of the Polymer Processing Society, PPS 2021
Country/TerritoryCanada
CityMontreal
Period26.09.202129.09.2021

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