Copolymers with periodic comonomer sequences

Abstract

The free radical copolymerization and multipolymerization of olefins with acrylic monomers in the presence of acids has been studied. It was found that Bronsted acids are as suitable complexing agents for the acrylic comonomer as the up to now exclusively used Lewis acids.The effectiveness of the Bronsted acids, e.g. carboxylic acids, for obtaining alternating copolymers increased with the pKs value, and trifluoroacetic acid turned out to be the acid of choice. The variation of the Lewis acid-type complexation agents was extended by the zinc chloride diethylether complex which is advantageous over ZnCI, or other Lewis acids because of its good solubility and recycling practicability, which is also a feature of the Bronsted acids.The versatility of the new complexing agent systems was demonstrated in a series of co-and multipolymerizations, and ethyl cyanoacrylate was employed for the first time as electron acceptor comonomer. The properties of the copolymers with periodic comonomer sequences varied systematically with their composition, e.g. the glass transition temperature and the degree of crystallinity.

Macromolecular chemistry and physics 1994

“…I141 Progress has also been made in the synthesis of macromolecules with periodic sequences through copolymerization. [17] Alternating olefin-acrylate sequences produced as discussed above by copolymerization in the presence of acids, support the selectivity of polymer analogous reactions such as perfluorination. [15] The addition of quaternary ammonium salts to the zwitterionic polymerization of cyclic ketene acetals with cyanoacrylate results in strictly alternating copolymers with relatively high molar masses (Scheme 2).…”

1:2‐sequence‐regulated radical copolymerization of naturally occurring terpenes with maleimide derivatives in fluorinated alcohol

“…In addition to the occurrence of such spontaneous alternating sequences governed by the inherent monomer reactivities, the use of Lewis acid additives or polar solvents can enhance the formation of alternating sequences. This process is the result of coordination of the Lewis acid or the solvent to the polar substituent of the former monomer or formation of a charge‐transfer complex between these components, even when one or both of the monomers are homopolymerizable 6, 7, 31–39. However, higher‐ordered sequence control is generally difficult in chain‐growth copolymerization, especially in the radical copolymerization of vinyl monomers.…”

Polycyanoacrylates

“…These systems rely on the in situ generation of an anionic initiator from a neutral species, following absorption of light of an appropriate wavelength. The zwitterionic and radical copolymerization of cyanoacrylates has also been reported for a number of comonomers including vinyl ethers (44), ketene acetals (45), furan (46), vinyl ketones (47), and ethylene (48).…”