Ionic grafting

Abstract

Cation initiated polymerizations of various monomers were carried out in the presence of several polystyrene derivatives in an effort to obtain graft copolymers. No success was achieved in grafting with vinyl butyl ether, vinyl ethyl ether, isobutylene, N‐vinylpyrrolidone, or pinene under the particular experimental conditions employed. In the experiments involving vinyl n‐butyl ether, the presence of the various polystyrenes appeared to have no effect on the polymerization of this monomer or on the DP of the polyvinylbutyl ethers obtained. However, when styrene was polymerized in the presence of poly‐p‐methoxystyrene (PPMS), graft copolymer was readily obtained. The success of this reaction demonstrates the feasibility of preparing graft copolymers by an ionic mechanism and yields additional proof of an ionic chain transfer reaction with aromatic species in which the latter are incorporated into the chain. Data obtained on the styrene‐PPMS system are discussed in terms of a simple kinetic scheme. The molecular termination constant of PPMS was found to be only 1/67th of that of p‐methylanisole, a low molecular weight analogue. The low chain transfer effectiveness of PPMS is believed to be due to constraints placed on the availability of the transfer sites which are linked in a polymeric chain.

Formation of block and graft copolymers

“…An appreciable discoloration and chain degradation occurs however at the same time. Carbonium chain transfer reaction has also been used for grafting purposes, e. g. between a polystyrene carbonium growing chain with poly-p-methoxystyrene [82]; in this reaction aromatic substitution occurs in the course of the tin tetrachloride initiated polymerization. It has however been used very successfully recently by J a a c k s and K e r n [83], who copolymerize cationically trioxane with several polymers, as for example polyvinyl acetate, cellulose acetobutyrate, polyethyleneglycol terephtalate and polyvinyl butyral.…”

Indefinitely active aqueous cationic polymerizations, part I: Low cost, recyclable initiator systems

“…Yb(OTf) 3 is recyclable but reaction is slow, limited to PMOS, and MWs are low. One report indicated Yb(OTf) 3 produces high MW polyPMOS after prolonged reaction (i.e., days); albeit subsequent growth, via Friedel‐Crafts alkylative branching, could not be ruled out . Next, lipophilic phosphonic acids were employed for the aqueous polymerization of PMOS with greater success but cannot polymerize low reactivity olefins…”

“…One report indicated Yb(OTf) 3 produces high MW polyPMOS after prolonged reaction (i.e., days); [49] albeit subsequent growth, via Friedel-Crafts alkylative branching, could not be ruled out. [51] Next, lipophilic phosphonic acids were employed for the aqueous polymerization of PMOS with greater success but cannot polymerize low reactivity olefins. [52] An improvement to the aqueous approach was made when the lead author implemented chelating (i.e., 1,2-C 6 F 4 [B(C 6 F 5 ) 2 ] 2 ) perfluoroarylated Lewis acids (PFLAs) which can produce polymers of high MW from lower reactivity olefins (e.g., IB).…”

Study of oxidation after monoacrylate grafting on polyethylene

“…However, the methods of choice of surface modification remain various grafting types of chemistry, including photoinitiated grafting,20–22 living graft polymerization23 or ionic grafting 24. Amongst them, photoinitiated grafting polymerization‐based methods are the most efficient ones in terms of durability of polyolefin surface modifications 20–22, 25–28. The originality of the photochemical process lies in the fact that the radical sites are produced only at the surface of the polymer, by UV irradiation in the presence of a photosensitizer.…”