Living cationic polymerization of isobutyl vinyl ether (II): Photoinduced living cationic polymerization in a mixed solvent of toluene and diethyl ether

Abstract

ABSTRACT:A new method of preparation of living cationic polymer of isobutyl vinyl ether via photoinduced polymerization in the presence of diphenyliodonium iodide (DPII, initiator) and zinc iodide in a mixed solvent of toluene/diethyl ether, which was irradiated at Ϫ78°C for short period, was completed within 15 min. The reaction was allowed for further reaction in the dark until monomer was fully consumed. It was found that increase in the conversion of monomer to polymer during the irradiation is very limited. Confirmation of the linear dependence of numberaverage molar mass of resulting polymer on % conversion together with the fact that polymerization proceeds until monomer consumption, and controllability of number-average molar mass of resulting polymer, depending on the molar ratio of monomer and initiator, strongly suggests the living nature of this polymerization, unless reaction temperature becomes higher than 0°C, i.e., the absence of chain breaking process. The narrow molar mass distribution, whose polydispersity index values are less than 1.2, reveals that the rate of initiation where irradiation is usually completed within 15 min is much faster than that of propagation in cationic nature in this system. Effect of some major factors, such as solvent polarity and temperature, on the living nature of the polymerization was also investigated.

Photoinitiated Polymerization: Advances, Challenges, and Opportunities

“…249,250 Photochemically generated protonic acid reacts with IBVE to form the monomer HX adduct. The terminal carbon-halide bond in this adduct is activated by the coordinating effect of zinc halide.…”

Synthesis of Poly(isobutyl vinyl ether)-graft-Poly(ethylene oxide) Co-polymer with Pendant Methacrylate Functionality and Its Photo-curing Behavior

“…The details of synthesis and characterization have been reported in a previous paper [21]. In the present study, the backbone was designed as a random co-polymer of IBVE and VE-PEO-MA, and prepared by the photoinitiated living cationic polymerization [24][25][26][27][28][29]. The polymerization consists of two steps; (i) photoinduced adduct formation and (ii) subsequent propagation with activated by the coordinating effect of zinc iodide.…”

Photo‐Induced Cross‐Linking of Divinyl Ethers by Using Diphenyliodonium Salts With Highly Nucleophilic Counter Anions in the Presence of Zinc Halides

“…[18][19][20] However, the use of protonic acids as initiator leads to some problems associated with their handling. To overcome such problems, photoinitiated living cationic polymerization [21][22][23] of isobutyl vinyl ether (IBVE) using diphenyliodonium halides have been reported. In our concept, the adducts are generated photochemically, [21][22][23] and react with IBVE to form a halide-monomer adduct (Reaction 2 in Scheme 1).…”

“…To overcome such problems, photoinitiated living cationic polymerization [21][22][23] of isobutyl vinyl ether (IBVE) using diphenyliodonium halides have been reported. In our concept, the adducts are generated photochemically, [21][22][23] and react with IBVE to form a halide-monomer adduct (Reaction 2 in Scheme 1). The coordinating effect of the zinc halide employed as a catalyst allows activation of the terminal carbon-halide bond of the adduct and triggers generation of a suitable nucleophilic counter anion by stabilizing the growth of the carbocation, which leads to insertion of a weakly basic monomer (Reaction 3 in Scheme 1).…”