Determination of Small-Amount Polypropylene in Imported Recycled Polyethylene/Polypropylene Blends by Fourier Transform Infrared Spectroscopy

In the domestic production of recycled plastics, it is difficult to separate olefin polymers such as polyethylene and polypropylene. Therefore, the prerequisite for identifying the cargo-solid waste properties of recycled plastics is to determine the polymer composition. In this paper, Fourier transform infrared spectroscopy was used to detect polypropylene content in polyethylene and polypropylene blends. Under 2%-8% polypropylene content, an exponential relationship was shown in the ratio of characteristic peak area. This method features fast detection speed and accurate judgment. It can quickly determine whether the polypropylene content in the polyethylene and polypropylene blends is greater than 5% in the tariff inspection. Also, it can determine plastic solid waste attributes and identify whether polyethylene is mixed with a small amount of polypropylene content.