AB crosslinked polyurethanes through ionic crosslinking: Influence of crosslinking networks on physico chemical properties

Isocyanate-terminated prepolymers were synthesized using poly(tetramethylen e oxide)glycol of molecular weight 1000 (PTMG(1000)) with tolylene-2,4-diis ocyanate (TDI). The prepolymers were chain extended with N-methyldiethanola mine (N-MDEA) to form polyurethanes containing tertiary nitrogen. These pol yurethanes were crosslinked with bromine terminated polyurethane, poly(uret hane-imide), and poly(urethane-siloxane) through the formation of cationome rs at tertiary nitrogen sites across the backbone polyurethanes. The crossl inked cationomeric polyurethanes were characterized by Fourier Transform In frared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), mechanical an alyses, (static and dynamic), and static contact angles measurements. FTIR spectral studies confirms the formation of bromine terminated poly(urethane -imide) and poly(urethane-siloxane), as well as quaternization of the terti ary nitrogen which leads to crosslinking. A comparison of thermal stabiliti es of crosslinked polymers with respect to the chemical nature of bromine t erminated prepolymers (BTP) indicates improved thermal stability for poly(u rethane-imide) based ABCP. Stress-strain analysis shows high elongation val ues for poly(urethane-siloxane) and poly(urethane-imide) based ABCPs. Dynam ic mechanical analysis reveals better damping for poly(urethane-siloxane) b ased AB crosslinked polymers.