Poly(urethane-methacrylate)s. Synthesis and characterization

Abstract

A series of poly(ester-urethane-urea)s containing pendant methacrylate functionality has been prepared, characterized and formulated into polyurethane methacrylate elastomers using a prepolymer process. Poly(ester-urethane-methacrylate)s were polymerized in a two-step process: synthesis of an isocyanate terminated prepolymers prepared from an excess molar concentration of 4,4′-methylene diphenyl diisocyanate with poly(ester)diols [Mn∼2000] and reaction the product with hexamethylenediamine and neutralization with methacrylic acid.In general, these materials exhibit physical properties similar to those of linear segmented polyurethanes rather than conventional thermal or radiation-cured oligomer based on polyurethane methacrylates.The cured materials were characterized by IR, stress–strain, thermogravimetric and thermally stimulated depolarization current experiments. Properties were compared to a polyurethane elastomer control in which the variable was the polyester diols' modification. The polyester diols modification produces polymers with decreased modulus, tensile strength, elongation. The crosslinking process depresses crystallization of the soft segments and improves tensile properties and can obtain protective films and finish materials for leather industry.Introducing diamine and methacrylic structural units extends the hard urethane segments.