Calcium salt of mono(hydroxypentyl)phthalate [Ca(HPP)2] was synthesized by the reaction of 1,5-pentanediol, phthalic anhydride, and calcium acetate. Calcium-containing poly(urethane ethers) (PUEs) were synthesized by the reaction of hexamethylene diisocyanate (HMDI) or toluylene 2,4-diisocyanate (TDI) with a mixture of Ca(HPP)2 and poly(ethylene glycol) (PEG300 or PEG400) with di-n-butyltin dilaurate as a catalyst. We synthesized a series of calcium-containing PUEs with different compositions by taking the molar ratio of Ca(HPP)2 : PEG300 or PEG400 : diisocyanate (HMDI or TDI) as 2 : 2 : 4, 3 : 1 : 4, and 1 : 3 : 4 to study the coating properties of the PUEs. Blank PUEs without a calcium-containing ionic diol were also prepared by the reaction of PEG300 or PEG400 with HMDI or TDI. The PUEs were well characterized by fourier transform infrared spectroscopy, 1HNMR, −13C-NMR, solid-state cross-polarity/magic-angle spinning 13C-NMR, viscosity, solubility, and X-ray diffraction studies. The thermal properties of the polymers were also studied with thermogravimetric analysis and differential scanning calorimetry. The PUEs were applied as a top coat on acrylic-coated leather, and their physicomechanical properties were also studied. The coating properties of PUEs, including tensile strength, elongation at break, tear strength, water vapor permeability, flexing endurance, cold crack resistance, abrasion resistance, color fastness, and adhesive strength, were better than the standard values.
Dr. Jayakumar Rangasamy, Lee, Y. - S., and Nanjundan, S., “Synthesis and Coating Characteristics of Novel Calcium-containing Poly(urethane ethers)”, Journal of Applied Polymer Science, vol. 92, pp. 710-721, 2004.