Process for preparing polyalkenamers for packaging applications

A process for producing a polyalkenamer-containing composition, the process comprising:

• a) converting at least one cycloalkene by ring-opening metathetic polymerization to obtain a polyalkenamer-containing product mixture, and
• b) working up the polyalkenamer-containing product mixture by an extraction with CO2, thereby removing at least one monomer and/or at least one oligomer of the at least one cycloalkene to obtain the polyalkenamer-containing composition,
• wherein the extraction comprises at least two stages:
• b1) an extraction with liquid CO2 and then
• b2) an extraction with supercritical CO2, wherein the polyalkenamer-containing product mixture obtained in a) is in solid form and is granulated or pulverized to particles prior to b) working up the product mixture.