Synthesis of metal-containing polyurethanes from poly (tetramethylene glycol)

Abstract

Zinc and nickel hexadentate schiff base complexes (Znsa₂trien and Nisa₂trien) have been synthesized and used as chain extending agents for the synthesis of metal-containing polyureas and polyurethane-ureas. The reaction between Znsa₂trien and different diisocyanates were studied to obtain the information on the reactivity of the isocyanates with amines in Znsal₂trien. The diisocyantes employed were 4.4'-methylenebis (phenyl isocyanate) (MDI), 2, 4-toluene diisocyante (TDI) and hexamethylene diisocyanate (HMDI). The progress of polymerization reaction was followed by using infrared spectroscopy. The disappearance of isocyanate peak at 2275 cm⁻¹ was observed when the polymerization was completed. The results showed that the suitable isocyanate was MDI. Nickel-containing polyureas (NiM) were obtained from the polymerization reaction between Nisahtrien and MDI. Metal-containing polyurethane-ureas were synthesized by reacting poly (tetramethylene oxide) (PTMO) with MDI and Znsa₂trien or Nisa₂trien. The polymers have been characterized by IR spectroscopy, elemental analysis, solubility and viscosity. The liquid crystalline property of metal-containing polymers was investigated. It was found that these polymers did not show liquid crystalline property. However, the polymers showed good thermal stability. The resistance of polymers towards high temperature was investigated by thermogravimetric analysis (TGA) and measuring limiting oxygen index (LOI) values.