Selection criteria for recycled polyolefins from urban wastes by using TG analysis

Abstract

The thermal behavior of a mixture of recycled polyolefins (PE/PP fmix), variously colored recycledpolyolefins, recycled polyolefin blends and recycled polyolefin/PET blends was analyzed by thermogravimetry. Atmospheres of nitrogen and synthetic air were used to compare the effects of inert and oxidative medium. Four characteristic temperatures, T1, T2, T3 and T4, related to oxidative processes and atmospheric conditions, were defined. Relationships between T1, T2, T3 and T4 and comparing pigmented and transparent material allow assessing the effect of different pigments on volatilization, oxidation and onset temperatures of decomposition processes. These analyses provide preliminatry parameters for selecting acceptable processing temperature conditions of recycled household and engineering plastics, and provide a few criteria to select colored recycled polyolefins.