Master Thesis : On the Effectiveness of Selected Adsorbents in Reducing Odor of Recycled Polypropylene from Post-Consumer Waste and their Influence on Polymer Stabilization

Abstract

Degradation of residual impurities in post-consumer recycled polypropylene generates volatile organic compounds that cause malodor, limiting consumer acceptance and high-quality reuse. This master’s thesis evaluates the effectiveness of selected odor scavengers and their influence on polymer stability in post-consumer recycled polypropylene. An increase in oxidative sensibility was linked to the odor scavenger Tego Sorb PY 88 T.Q. and to a lower degree to BYK MAX OR 4207. Both odor scavengers did not significantly decrease the odor intensity. The other odor scavengers Rescofil 1476-400, Rescofil 1476–400 Plus, Zeoflair 100 and a custom surface modified version of Zeoflair 100 did significantly alter the odor profile, with Zeoflair 100 performing as the most efficient odor adsorption additive. Nevertheless, for high requirement applications further increases in odor adsorption efficiency is needed. No negative impact on polymer stabilization was noted. Rather, some rheological measurements indicate a slight support of these odor scavengers for polymer stabilization; possibly by the adsorption of hydro peroxides.