Chemical stability: PE is polar crystalline polymer, it has excellent chemical stability, it can acid at room temperature, alkali and salt solution, such as hydrochloric acid, hydrofluoric acid, phosphoric acid, formic acid, acetic acid, ammonia, sodium hydroxide, potassium hydroxide and all kinds of salt solution (including oxidising potassium permanganate solution and dichromate solution, etc.), even under the high concentration of PE had no significant effect. But concentrated sulfuric acid and nitric acid and other antioxidants will slowly erode PE, temperature rise, after oxidation is more significant.
PE under the temperature does not dissolve in any solvent, but the solubility parameter of similar solvent can make its swelling, with the increase of temperature, PE crystalline gradually destroyed, macromolecule and enhanced the role of the solvent, when after reaching a certain temperature PE soluble in fat hydrocarbon, aromatic hydrocarbon, halogenated hydrocarbon, etc. Such as LDPE benzene soluble in 60 ℃, HDPE benzene soluble in 80 ~ 90 ℃, more than 100 ℃ after both soluble in toluene, trichloroethylene, four hydrogen naphthalene, ten hydrogen naphthalene, petroleum ether, mineral oil and paraffin. But even at high temperatures PE is insoluble in water, fatty alcohol, acetone, ethyl ether, glycerin and vegetable oil. PE solubility in organic solvent and swelling degree decreases with the increase of relative molecular mass and degree of crystallinity, therefore, HDPE has better chemical stability than LDPE.
