Monofunctional and Telechelic Polyethylenes Carrying Phosphonic Acid End Groups

Abstract

Monofunctional or telechelic polyethylenes (PEs) carrying phosphonic acid end groups are obtained from functional PE produced by catalyzed chain growth (CCG) on magnesium. CCG is first used to produce iodo-end-functionalized PE (PE-I) that is efficiently turned into phosphonate end-functionalized PE (PE-P(O)(OEt) ) in the presence of triethylphosphite through the Michaelis-Arbuzov reaction. A simple treatment of the resulting PE-P(O)(OEt) with bromotrimethylsilane leads to the targeted phosphonic acid end-functionalized PE (PE-P(O)(OH) ) for the first time. Vinyl-end-functionalized analogs (Vin-PE-P(O)(OEt) ) are produced using vinyl-end-functionalized PE-I (Vin-PE-I) recently obtained through CCG. A cross-metathesis reaction is then employed to couple Vin-PE-P(O)(OEt) and produce after treatment with bromotrimethylsilane the corresponding unprecedented α-ω-(diphosphonic acid) telechelic PE ((OH) (O)P-PE-P(O)(OH) ).

One-Pot Synthesis of Block Copolymers Containing a Polyolefin Block

“…25% of all polymers produced . Alternatively, living insertion polymerization of olefins followed by end-group modification has been used to synthesize polyolefin-containing block copolymers. ,, In this polymerization, the growing polyolefin remains attached to the metal center, and the reactivity of the metal complex toward polar groups is used to convert the polyolefin into a macroinitiator capable of reacting with polar monomers. , The pitfall of living polymerizations is their scalability due to the high cost of the catalyst and the low productivity of the system; i.e., a living polymerization yields only one chain per initiator. , The low productivity problem has been resolved via the living catalytic chain transfer polymerization. − Chain transfer agents, such as aluminum, zinc, and magnesium alkyls, have been successfully employed for the formation of polyolefin-containing block copolymers. ,− In a living catalytic chain transfer polymerization each polyolefin is attached to a metal alkyl complex. The high oxophilicity of the metal is again used to yield the corresponding macroinitiators. , While successful, stereoregular living chain transfer polymerization remains very difficult to achieve; thus, examples of isotactic polypropylene-containing block copolymers based on this method remain scarce in the literature. , …”