A calcium salt of mono(hydroxypentyl)phthalate [Ca(HPP)2] was synthesized by the reaction of 1,5-pentanediol, phthalic anhydride, and calcium acetate. Four different bisureas such as hexamethylene bis(ω,N-hydroxyethylurea), tolylene 2,4-bis(ω,N-hydroxyethylurea), hexamethylene bis(ω,N-hydroxypropylurea), and tolylene 2,4-bis(ω,N-hydroxypropylurea) were prepared by reacting ethanolamine or propanolamine with hexamethylene diisocyanate (HMDI) or tolylene 2,4-diisocyanate (TDI). Calcium-containing poly(urethane-urea)s (PUUs) were synthesized by reacting HMDI or TDI with 1:1 mixtures of Ca(HPP)2 and each of the bisureas with di-n-butyltin dilaurate as a catalyst. The PUUs were well characterized by Fourier transform infrared spectroscopy, 1H and 13C NMR, solid-state 13C–cross-polarization/magic-angle spinning NMR, viscosity, solubility, elemental analysis, and X-ray diffraction studies. Thermal properties of the polymers were also examined with thermogravimetric analyses and differential scanning calorimetry.
Dr. Jayakumar Rangasamy and Nanjundan, S., “Calcium-containing poly(urethane-urea)s: Synthesis, spectral, and thermal studies”, Journal of Polymer Science Part A: Polymer Chemistry, vol. 42, pp. 1809-1819, 2004.