Study On The Preparation And Properties Of Polyethylene Wax From Pyrolysis Of Polyethylene In Solvent

Polyethylene wax is one of the important petroleum chemicals withstable chemical and wear-resistant property, high hardness and soapy feeling.So it can be widely used. In recent years, domestic and foreign petrochemicalindustry had been made greater progress and the demand of polyethylene waxis also growing fast. This paper studies the preparation and properties ofpolyethylene wax from pyrolysis of polyethylene. We obtain someconclusions.From the results of several solvents in pyrolyzing polyethylene, wefind that solvent A is the best and B is the secondary. Results show that mixedsolvent with the ratio of A/B=2:3is the optimal for preparing polyethylenewax. Factors affecting the property and the yield of products are temperature,time and ratio of solvent to feed. Temperature is the main factor and time isminor factor. The yield of high-density polyethylene is slightly higher than that of low-density polyethylene. The products are wihte or yellow powder.Through orthogonal experiments, we obtain the suitable condition forpyrolyzing LDPE, that is310℃,5hand1:1.5(ratio of solvent to feed). Theyield of PEW is97.33%. The reasonable condition for pyrolyzing HDPE is320℃,3hand1:1(ratio of solvent to feed). Its yield reaches98.1%.The relative molecular weight of the polyethylene wax from HDPE isabout2000-3000g/mol and the melting point ranges from120℃to130℃.The relative molecular weight of the polyethylene wax from LDPE is around2000-2700g/mol, the melting point is about90-110℃and the density rangesfrom0.9g/cm3to1.0g/cm3.Pyrolysis of waste plastics to prepare PEW was also carried out. Thereasonable condition for pyrolyzing waste plastics is320℃,4h,1:1(ratio ofsolvent to feed) and300r/min. The product is the white powder and the yieldis up to98.85%. Temperature is the most important factor, the solvent/feedratio is the secondary and time has the least effect on the yield.