Chain extension of oligodiols by means of cyclic acetals

Abstract

We have studied the reaction of 1,3‐dioxolane with trifluoromethanesulfonic acid in the presence of α,ω‐dihydroxypolytetrahydrofurane and α,ω ‐ dihydroxypolystyrene. Besides polymerization of 1,3‐dioxolane we have observed the occurence of a fast coupling reaction between the initial oligodiols. The mechanism has been studied using a monohydroxylated polystyrene and a model compound, 3‐phenyl‐1‐butanol. We have shown that coupling takes places through transacetalization even under the mild conditions used Ethylene glycol is produced and an acetal bridge is formed between oligodiols. Conditions have been found where high‐molecular‐weight polymer is formed through this polycondensation, in the absence of homopoly(1,3‐dioxolane).

Cationic copolymerization of ε‐caprolactone and L,L‐lactide by an activated monomer mechanism

“…These characteristic features of cationic ring‐opening polymerization proceeding by the AM mechanism have stimulated interest in expanding the scope of its application to other classes of monomers. Thus, the cationic AM mechanism has been applied to the homopolymerization and copolymerization of epoxides,7–12 oxetanes,13 and cyclic acetals,14, 15 as well as polymerizations of cyclic esters (lactones), including cyclic carbonates 16–22. Recently, the cationic homopolymerization of lactide proceeding by the AM mechanism has also been described 23…”

Synthesis of block and graft copolymers of tetrahydrofuran and cyclic acetals

“…Care has to be taken to reach the monomer equilibrium concentration before stopping the reaction because we have shown that in the early stages of the polymerization the reactions do not involve a simple "Activated-Monomer Mechanism" but that extensive transacetalization takes place concomitantly (Ref. 29).…”

Formation of cyclic structures in the cationic ring-opening polymerization of 1,3-dioxolane

“…Transacetalization side reactions between diols and DXL monomers were shown to occur in the beginning of the reaction. 8,17 However, the resulting polymer molecules, though doubled in molecular weight, still carry the desired end-standing OH functions.…”