Exciplex laser‐induced polymerization of pure ethylene at high pressure

Abstract

Abstract Pure ethylene is photo‐polymerized with an exciplex laser on the KrF line (248 nm) at temperatures from 190°C to 230°C and for pressures up to 3 200 bar. The radical reaction is directly monitored via quantitative high‐pressure high‐temperature near infrared spectroscopy. Toward higher densities and temperatures, the overall quantum yield increases and up to several thousand ethylene molecules are polymerized by one absorbed laser photon. A kinetic scheme is presented which adequately describes the polymerization kinetics as a function of temperature, overall density, laser pulse energy, and conversion. Termination rate coefficient k t is found to decrease in the initial polymerization period, whereas a single value of k t is sufficient to represent kinetic data in the extended conversion range from 20% to 70%.