Ethylene free radical polymerization in supercritical ethylene/CO₂ mixture

Abstract

Ethylene free radical polymerization in supercritical CO2/ethylene mixture under mild conditions (<100 °C and <300 bar) has been achieved to produce polyethylene, functionalized with benzoate moieties when benzoyl peroxide was used as initiator.

On the Precipitation Copolymerization of 1‐Octene and Glycidyl Methacrylate in Supercritical Carbon Dioxide

“…The use of supercritical carbon dioxide (sc‐CO 2 ) for the synthesis of polymers can be considered a green chemistry approach as it diminishes the use of toxic organic solvents not only for the synthesis but also for the purification of the resulting polymer. [ 1–13 ] Due to the fact that most polymers are not soluble in sc‐CO 2 , except for fluoropolymers and polysiloxanes, polymerization in sc‐CO 2 can be performed in heterogeneous phase by using appropriate stabilizers or via precipitation polymerization. Examples include the homopolymerization of polar monomers, such as acrylic acid [ 13 ] and methyl and glycidyl (meth‐)acrylates, [ 9–12,14,15 ] and nonpolar monomers, such as styrene [ 7 ] and recently ethylene.…”

“…Examples include the homopolymerization of polar monomers, such as acrylic acid [ 13 ] and methyl and glycidyl (meth‐)acrylates, [ 9–12,14,15 ] and nonpolar monomers, such as styrene [ 7 ] and recently ethylene. [ 1 ] Yet the direct copolymerization of both polar and nonpolar monomers has not been reported using sc‐CO 2 as a reaction medium probably due to the immiscibility of both kinds of monomers and the resulting copolymer. Despite the fact that most polymers are not soluble in CO 2 the contrary is valid to a certain extent.…”