Design of sec-Benzyl Vinyl Ethers toward the Synthesis of Alternating Copolymers Composed of Vinyl Alcohol and Vinyl Ether Units

Abstract

In this work, we designed benzyl vinyl ethers carrying alkyl substituents at the benzyl position (i.e., sec-BnVEs) as bulky, reactive, and transformable monomers to realize the alternating cationic copolymerization with an alkyl vinyl ether (VE). In particular, the isopropyl substitution caused not only the bulkiness to suppress the successive propagation but also an enhancement of the vinyl group reactivity to promote crossover propagation with a less bulky VE comonomer. The isopropylsubstituted BnVE (iPr-BnVE) underwent living cationic alternating copolymerization with n-butyl VE (nBVE), and the alternating propagation was strongly suggested by the reactivity ratios. The subsequent deprotection of the sec-benzyl pendant afforded the vinyl alcohol (VA)−nBVE alternating copolymer, and the corresponding statistical copolymer was also synthesized by using the nonsubstituted monomer (BnVE) instead of iPr-BnVE. The alternating copolymer exhibited a higher glass transition temperature, which likely stems from the uniform and efficient hydrogen-bonding formation due to the periodic sequence.

Alternating Graft Copolymer Carrying PLA Graft Chains at Every Other Unit: Sequence Impacts on Crystallization Behaviors

“…On the other hand, we have recently achieved synthesis of AB alternating copolymers made of commodity monomer units, such as (meth)acrylate, styrene, and acrylamide, through post-polymerization modification strategies. , The crucial viewpoint is the comparison with the corresponding 1:1 random or statistical copolymer to clarify the features derived from the alternating sequence on the basis of the periodic array of pendant groups and none of the composition distribution. − Other research groups have also studied sequence-specific physical properties of alternating copolymers, such as glass-transition temperature and self-healing property. , We came up with an idea of synthesis for an “alternating graft copolymer” where graft chains are periodically attached at every other vinyl monomer unit as a sequence-controlled graft copolymer. Some examples have been reported for the syntheses of such alternating graft copolymers via alternating copolymerization.…”