Synthesis of graft copolymers based on selective living cationic polymerization using an acetal group with a combination of Lewis acids

Synthesis of block or graft copolymers containing poly(styrene derivative) segments by living cationic polymerization using acetal moieties as latent initiating sites

“…Toluene (Wako; >99.5%), dichloromethane (CH 2 Cl 2 ; Wako; >99.0%), and hexane (Wako; 96.0%) were dried using solvent purification columns (Glass Contour; Solvent Dispensing System). The acetal-containing VE 2-(2,2-dimethoxy)ethoxyethyl VE (DMEVE) was prepared from an addition reaction of 2-hydroxyethyl VE with bromoacetaldehyde dimethyl acetal according to a literature method 8 and distilled three times over calcium hydride. The adducts of IBVE with HCl [IBVE-HCl; CH 3 CH(OiBu)Cl] or acetic acid [IBEA; CH 3 CH(OiBu)OCOCH 3 ] were prepared from an addition reaction of IBVE with HCl or acetic acid according to a literature method 12 respectively.…”

“…Poly(IBVE 78 -co-DMEVE 4 ) (Scheme 2), a macroinitiator, was prepared via the living cationic copolymerization of IBVE with DMEVE, an acetal-containing monomer. 8 The acetal moieties were intact during the copolymerization with Et 1.5 AlCl 1.5 as a catalyst. ARTICLE% Journal(Name% 6%|%J.…”

“…The most unexpected outcome was the lack of polymerization in the presence TiCl 4 , which induces the living polymerization of IBVE using TME. 8 One of the main roles of TiCl 4 is the generation of the real initiating species, i.e., a ß-methoxy ARTICLE% Journal(Name% 4%|%J. !Name.,%2012,%00,%1=3% This%journal%is%©%The%Royal%Society%of%Chemistry%2012% methyl VE-hydrogen chloride adduct, via the exchange reaction between the methoxy group of TME and the chloride anion of TiCl 4 .…”

“…Our group recently achieved Lewis acid-selective activation of acetal functional groups for controlled cationic polymerization of vinyl ethers (VEs), leading to the facile synthesis of block or graft copolymers using only the cationic mechanism without post polymerization transformation of functional groups. 8 Systematic investigation revealed that a highly efficient acetal activation for the initiation of VE polymerization was achieved using an oxophilic metal chloride, such as TiCl 4 and ZrCl 4 , whereas chlorophilic metal chlorides, such as ZnCl 2 and SnCl 4 , were inert. Thus, an acetal-inert Lewis acid was used to prepare a macroinitiator with acetal moieties in the side chains via living cationic copolymerization of an acetal-containing VE monomer.…”

“…8 Systematic investigation revealed that highly efficient acetal activation for the initiation of VE polymerization was achieved using an oxophilic metal chloride, such as TiCl 4 and ZrCl 4 , whereas chlorophilic metal chlorides, such as ZnCl 2 and SnCl 4 , were inert. Thus, an acetal-inert Lewis acid was used to prepare a macroinitiator with acetal moieties in the side chains via living cationic copolymerization of an acetal-containing VE monomer.…”