Synthesis and characterization of calcium containing poly(urethane-ether)s

Calcium containing poly(urethane-ether)s (PUEs) were synthesized by the reaction of hexamethylene diisocyanate or toluylene 2,4-diisocyanate (HMDI or TDI) with a mixture of calcium salt of mono(hydroxybutyl)phthalate Ca(HBP)₂] and polyethylene glycol (PEG₂₀₀ or PEG₄₀₀). A series of calcium containing PUEs having different composition were synthesized by taking the mole ratio of Ca(HBP)₂:PEG₂₀₀ or PEG₄₀₀:diisocyanate (HMDI or TDI) as 3:1:4, 2:2:4 and 1:3:4 to study the effect of calcium content on the properties of the copolymer. The structure of the polymers were confirmed by IR, ¹H-NMR, ¹³C-NMR, and solid state ¹³C-CP-MAS NMR. The polymers were soluble in dimethyl sulfoxide and dimethyl formamide. The initial decomposition temperature of the polymers decreases with increase in calcium content. The T_g value of PUEs increases with increase in calcium content and decreases with increase in soft segment content and length. A single T_g value is observed for the calcium containing PUEs based on PEG₂₀₀ shows the presence of homogeneous phase. However, two T_g values for the PUEs based on PEG₄₀₀ for various composition of Ca(HBP)₂, PEG₄₀₀ and diisocyanate (HMDI or TDI) shows the presence of heterogeneous phase. The viscosity of the calcium containing PUEs increases with increase in the soft segment content as well as its length and decreases with increase in calcium content. X-ray diffraction patterns of the polymers show that the HMDI based polymers are partially crystalline and TDI based polymers are amorphous in nature. The dynamic mechanical analysis of the calcium containing PUEs based on HMDI shows that at any given temperature modulus (g^′ and g^″) increases with increase in the ionic content in the polymers.