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).