Polyethylene (PE) is a thermoplastic resin obtained by polymerization of ethylene. In industry, the copolymers of ethylene and a small amount of alpha olefins are also included. Polyethylene is odorless, non-toxic, and feels like wax. It has excellent low temperature resistance (the lowest temperature is up to -100~-70 degrees C). It has good chemical stability and can withstand most acid and alkali erosion. At normal temperature, it is insoluble in general solvent, with small water absorption and excellent electrical insulation. In October 27, 2017, the WHO International Cancer Research Institute published a list of carcinogens on the list of 3 types of carcinogens.
A kind of polyethylene (PE) plastic which we often use is polyethylene (PE). Polyethylene is the simplest structure of polymer, and it is also the most widely used polymer. It is made up of repeated - CH2 - unit connections. Polyethylene is formed by the addition of ethylene (CH2=CH2) to polymerization.
The performance of polyethylene depends on the way it is polymerized. High density polyethylene (HDPE) was formed by Ziegler-Natta polymerization under the medium pressure (15-30 atmospheric pressure) organic compounds. Under these conditions, the polythene molecules polymerized are linear, with a long molecular chain and a molecular weight of hundreds of thousands. If it is at high pressure (100-300MPa) and high temperature (190 – 210C), free radical polymerization under peroxide catalysis will produce low density polyethylene (LDPE), which is a branched chain structure.