A Characterization Method for Evaluating Additives Suitable for Odor Control in Plastics

Recycling is a key element in achieving a sustainable circular plastics economy, which is necessary to combat climate change and pollution. However, many challenges remain. One major challenge is the insufficient quality of recycled materials, which limits their use to low-value applications. One factor with considerable impact on the quality is the presence of an unpleasant odor caused by absorbed impurities, decomposition of the plastic during the use phase, and the recycling process. Unpleasant odors in plastics can be addressed by different technologies, such as washing and extraction processes during recyclate processing, or the incorporation of plastic additives for odor control. However, the effectiveness of an additive for odor control depends highly on the odorant and the polymer type of the recyclate. Finding an additive which meets the requirements is currently a time-consuming and costly process, which involves the preparation of test specimens and an olfactory evaluation. There is consequently a high interest in developing a simple and fast process to measure the effectiveness and efficiency of additives for odor control. In this study, we present a straightforward and rapid characterization method to measure the effectiveness of a substance in absorbing specific volatile organic compounds (VOCs) released from a recyclate, in order to pre-evaluate its suitability as an odor absorber.