Mathematical Modeling of Free-Radical Ethylene Copolymerization in High-Pressure Tubular Reactors

Abstract

A comprehensive mathematical model is developed for the free-radical copolymerization of ethylene with various comonomers (e.g., vinyl acetate, methyl or ethyl acrylate, and acrylic or methacrylic acid) in high-pressure tubular reactors. Polar copolymers usually exhibit lower crystallinity and yield strength than low-density polyethylene grades and are used for applications requiring flexibility, toughness, stress-cracking resistance, and adhesion to coatings. In the present study, a detailed kinetic mechanism is proposed to describe the molecular and compositional developments in the free-radical copolymerization of ethylene with a comonomer. On the basis of the postulated kinetic mechanism, a system of differential mass balance equations are derived for the various molecular species, total mass, energy, and momentum in the polymerization system. The model equations are coupled with a set of algebraic equations for estimating the thermodynamic and transport properties of the reaction mixture. The number ...