Synthesis of a new degradable polyurethane elastomer containing polyacetal soft segments

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.