Synthesis of polyurethanes and investigation of their hydrolytic stability

Polyurethane films were prepared with poly(tetramethylene oxide) prepolymer, terminated with hexamethylene diisocyanate, and a polyfunctional diester of oxalic acid and glycerol, di-(2,3-dihydroxypropyl) oxalate (DHPO), or its mixtures with 3,6-dioxaoctane-1,8-diol (DOD) as chain extender. Some mechanical characteristics of these films were ascertained. These samples are more readily hydrolyzed than those prepared with DOD alone; the hydrolyzability can be regulated by changing the DHPO/DOD ratio. The change in structure during the hydrolysis was investigated by differential thermal analysis (DTA).