Synthesis and characterization of macrodiols and non-segmented poly(ester-urethanes) (PEUs) derived from α,ω-hydroxy telechelic poly(ε-caprolactone) (HOPCLOH): effect of initiator, degree of polymerization, and diisocyanate

Nine different macrodiols derived from alpha,omega-hydroxy telechelic poly(epsilon-caprolactone) (HOPCLOH) were prepared by ring-opening polymerization of epsilon-caprolactone (CL) using three linear aliphatic diols (HO-(CH2)n-OH, where n = 4, 8, and 12) as initiators and catalyzed by ammonium decamolybdate (NH4)8[Mo10O34]. The crystallization temperature (Tc) and crystallinity (xi) were relatively high for HOPCLOH species with a long aliphatic chain [-(CH2)12-] in the oligoester. Also, HOPCLOH was the precursor of twenty-seven different poly(ester-urethanes) (PEUs) with various degrees of polymerization (DP) of HOPCLOH and three types of diisocyanates such as 1,6-hexamethylene diisocyanate (HDI), methylene diphenyl diisocyanate (MDI), and 4,4 '-methylenebis (cyclohexyl isocyanate) (HMDI). HOPCLOH exhibited the melting temperature (Tm) and crystallinity (xi) with a proportional dependency to the degree of polymerization (DP). PEUs showed significant thermal and mechanical properties, which had a direct correlation in terms of the type of DP and diisocyanate. PEUs derived from HDI versus MDI or HMDI exhibited an apparent effect where aliphatic diisocyanate (HDI) induced a significant xi with respect to aromatic and cyclic diisocyanate (MDI or HMDI). The profile of PEUs films according to mechanical properties is mainly a plastic behavior. The chemical nature and properties of HOPCLOH and PEUs were characterized by NMR, FT-IR, GPC, MALDI-TOF, DSC, and mechanical properties. This study explores three different factors such as the initiator, degree of polymerization and diisocyanate on the properties of macrodiols and poly(ester-urethanes) (PEUs).