How to identify different types of plastic？

The basic method of distinguishing different types of plastic and its composition is through some commonly used analysis and detection instruments, such as infrared spectrophotometer, chromatograph, x-ray diffractometer, colorimetric instrument, nuclear magnetic resonance instrument and so on. However, the general plastic packaging printing plant does not have such equipment, so if a more simple method can quickly determine an unknown plastic, which in the actual work is more valuable. The easiest initial identification method is combustion method and tear identification method.

(1) combustion method: thermosetting plastic in the heat will be brittle, hair coke, but not soft; and when a certain temperature to reach a certain temperature soft, or even melting, which is the system to identify the basic boundaries of these two types of plastic.

Chlorine, phosphorus. Fluorine and silicon plastic are not easy to fire or self-extinguishing, on the contrary, sulfur and nitro-based plastic is easy to fire and burning. Ethylene, propylene, isobutylene and other plastic and alkane compounds similar structure, combustion characteristics are similar. Compounds with benzene rings and unsaturated double bonds (such as diene polymers or copolymers) are black smoke when burned.

When the plastic heat will break down and produce special smell. For example: polymethyl methacrylate, polystyrene, polyoxymethylene can be heat decomposition into monomer; polyethylene, polypropylene is cracked into carbon atoms ranging from carbon; polyvinyl chloride, polyvinylidene chloride decomposition of hydrogen chloride The All of these heating and burning phenomena, can be used for classification and identification of plastic basis.

(2) plastic composite film tear identification method: the blade will be cut with 1cm composite film openings, and then hand tear. Such as easy to tear, is a cellulose film. If it is not easy to tear is a polypropylene film. If it is difficult to tear is a polyethylene film, directional Yixiang film or polyester film.

    Although the large usage of polystyrene, the polystyrene are disposable, which can easily become the white pollution, so polystyrene recycling is very necessary to protect our environment. And then we can reuse it to do some other products.