Research On Manufacturing Macromolecule Wax By Pyrolysis Of Pe At High Temperature In Single-Screw Extruder Reactor

Polyethylene wax (PEW) also known as macromolecule wax, an important additive was usually used in plastics, dyes, paints and many other industries. In recent years, its demand is increasing. In this paper, the cracking reactor is single-screw extruder, and polyethylene was selected as pyrolysis feedstock. The effects of different pyrolysis process on properties of polyethylene wax were studied. Details are as follows:1. Considering the existing single-screw extruder, a connection pipe with certain length was designed to extend the pyrolysis time of polyethylene?The hot liquid polyethylene wax was extruded into the self-designed cooling tank by extruder in order to be cooled and stored until it was taken out. So the experimental device platform was set up with regard to continue producing wax by single-screw extruder at high temperature.2. Based on the pyrolysis mechanism of polyethylene, analyzing the performance parameter of polyethylene wax which was obtained at various process conditions, kinetic parameters of HDPE pyrolysis can be determined in the experimental device. Accordingly, the kinetic model of high-density polyethylene (HDPE) pyrolysis in the experimental device was established. Therefore, the molecular weight of polyethylene wax, produced by HDPE cracking at different process conditions, can be predicted via using above model, and has verified by experimental means.3. This article focuses on the effects of pyrolysis temperature and screw speed on the properties of polyethylene waxes which were obtained by low density polyethylene(LDPE) and HDPE pyrolysis, the results realized that the product manufactured by HDPE pyrolysis has narrower molecular weight distribution and better thermal stability than which obtained by LDPE cracking. In this study, the molecular weight of polyethylene wax can be controlled by adjusting the pyrolysis process. Under the optimized cracking process, cracking temperature 420? and screw speed lOrpm, HDPE pyrolysis can obtain the polyethylene wax with viscosity-average molecular weight 3732, melting point 125.5?, thixotropic index less than 1×10-1 mm and thermo-gravimetric rate less than 5%.