Synthesis of polyureas and polyurethanes containing heterocycles

Abstract

This research involved the synthesis of heterocyclic polyureas, polyurethanes and polyurethane-ureas, which was done by the polymerization reaction of heterocyclic compounds containing diamine and diol functional groups with disocyanate compounds at the mole ratio 1:1. The heterocycles used were proflavine (PF), new fuchsin (NF) and bromphenol blue (BPB). The diisocyanates employed were isophorone diisocyanate (IPI), 4,4 methylenebis (phenyl isocyanate) (MDI), tolylene 2,4-diisocynate terminated poly (1,4-butanediol) prepolymer (PB900) and tolylene 2.4-diisocynate terminated poly (propylene glycol) prepolymer (PP1000). The reaction between isophorone diisocyanate (IPI) and different heterocycles were studied to obtain the information on the reactivity of diamine group or diol group in heterocyclic compounds towards diisocyanate group in the polymerization reaction. The progress of polymerization reaction was followed by using infrared spectroscopy. The disappearance of isocyanate peak at 2270 cm (supperscript -1) was observed when the polymerization was completed. The obtained information in this step was used in the synthesis of heterocyclic polyureas, polyurethanes and polyurethane-ureas in the next step. The polymers were characterized by FTIR spectroscopy, NMR spectroscopy, elemental analysis, solubility and viscometry. Heat resistance of polymers was investigated by thermogravimetric analysis (TGA) and measuring limiting oxygen index (LOI) values. It was found that the polyureas based on proflavine and new fuchsin showed good thermal stability.