Synthesis of Glycolate-Containing Poly(tetramethylene glycol)s and Properties of Degradable Polyurethanes Prepared Therefrom

摘要

Glycolate-containingp oly(tetramethyleneg lycol)s (PTHF-GA-OH) were prepared by the reaction of bifunctional living poly(tetrahydrofuran) with lithium bromide followed by the substitution reaction of the produced bromide end groups with potassium glycolate. The obtained polyols were reacted with 4,4'-diphenylmethane diisocyanate and then with 1,4-butanediol to give a polyurethane with degradable ester moieties. The treatment of the obtained polyurethane (PTHF-GA-BD-PU) with potassium hydroxide in tetrahydrofuran/ethano(l9 /1 v/v) solvent in the presence of a small amount of water caused hydrolysis reaction of the glycolate ester linkages to give the mixture of PTMG and the urethane oligomers. The extraction of PTMG with methylene chloride from the mixture resulted in the recovery of PTMG in over 70% yield based on the poly(tetrahydrofuran)s egments of PTHF-GA-BD-PU.E nzymatic degradation of PTHF-GA-BD-PU was carried out with lipase as a catalyst. The heterogeneous reaction with film specimens in water using phosphate buffer solution (pH 7.4) at 37 °C caused the decrease in the molecular weight of PTHF-GA-BD-PU. This is probably due to the lipase-catalyzed hydrolysis of the glycolate ester groups of PTHF-GA-BD-PU.