Organic solvents effect on physical and mechanical properties of polyethylene

High-density polyethylene (PE) swelling in organic solvents, orthodichlorobenzene and orthoxylene, was investigated. The PE specimen swelling kinetics was described with the first-order equation. For the first time, the PE specimen swelling rate constant was shown to decrease with increasing thickness of the specimens. The equilibrium PE specimen swelling was evaluated. It was found that equilibrium swelling independent of specimens’ thickness. PE specimen storage in organic solvents was shown to change its mechanical characteristics (tensile strength, Young’s modulus, and elongation at break) due to polymer plasticization. We showed that an increase in flexibility and elongation at break becomes noticeable after relatively short-term immersion of the PE specimens into these organic solvents. However, the tensile strength of swollen specimens remains enough high. The interaction between polymer chains and solvent molecules was not detected. The results obtained are important for design and operation of PE coatings and PE products, such as pipes, tanks, and other accessories subjected to contacts with oil products.