To establish the optimum conditions for obtaining high molecular weight polyacetals by the self‐polyaddition of vinyl ethers with a hydroxyl group, we performed the polymerization of 4‐hydroxybutyl vinyl ether (CH2CHOCH2CH2CH2CH2OH) with various acidic catalysts [p‐toluene sulfonic acid monohydrate, p‐toluene sulfonic anhydride (TSAA), pyridinium p‐toluene sulfonate, HCl, and BF3OEt2] in different solvents (tetrahydrofuran and toluene) at 0 °C. All the polymerizations proceeded exclusively via the polyaddition mechanism to give polyacetals of the structure [CH(CH3)OCH2CH2CH2CH2O]n quantitatively. The reaction with TSAA in tetrahydrofuran led to the highest molecular weight polymers (number‐average molecular weight = 110,000, weight‐average molecular weight/number‐average molecular weight = 1.59). 2‐Hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, cyclohexane dimethanol monovinyl ether, and tricyclodecane dimethanol monovinyl ether were also employed as monomers, and polyacetals with various main‐chain structures were obtained. This structural variety of the main chain changed the glass‐transition temperature of the polyacetals from approximately −70 °C to room temperature. These polyacetals were thermally stable but exhibited smooth degradation with a treatment of aqueous acid to give the corresponding diol compounds in quantitative yields. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4053–4064, 2002

A new polyurethane elastomer with polyacetal soft segments (1) was synthesized by the reaction of hydroxy‐terminated telechelic polyacetals (3) with an excess amount of 4,4′‐diphenylmethane diisocyanate and by the subsequent chain‐extension reaction with 1,4‐butanediol. Polyurethane 1 exhibited good mechanical and thermal properties as an elastomer and underwent smooth degradation with a treatment of hydrochloric acid in tetrahydrofuran at room temperature, and 1,4‐butanediol and urethane hard‐segment residues were produced as degradation products in quantitative yields. These properties of 1 were compared with those of a conventional polyurethane (2) containing poly(tetramethylene ether) glycol (4 or PTMG) as soft segments.

Hydroxyl-terminated telechelic polyacetals were synthesized by polyaddition of 4-hydroxybutyl vinyl ether (HBVE; CH2=CH-O-CH2CH2CH2CH2-OH) in the presence of 1,4-butanediol with ptoluenesulfonic acid monohydrate (TSAM) as a catalyst in tetrahydrofuran (THF) at 0 °C. The structural analysis showed that the produced polymers had hydroxyl groups at both the chain ends. The polyacetals thus obtained were stable under neutral and basic conditions, but exhibited smooth degradation with treatment of acid to give 1,4-butanediol in quantitative yield. The polymers were highly viscous liquid and its glass transition temperature (g) was -72 °C.