Synthesis and characterization of linear and crosslinked poly(urethane urea) elastomers with triazine moieties in the main chain

Abstract

A series of new poly(urethane urea) is synthesized via a two-step poly-addition process from polyether, 1,6-hexamethylene diisocyanate, 2,4-diamino-6-phenyl-1,3,5-triazine and different crosslinkers: glycerin or castor oil. The hard to soft segment ratio (OHpolyol/NCO/NH2chain extender) was varied systematically from 1/2/1 to 1/4/3. Poly(tetramethylene glycol) of molecular weight 1,400 was used as the soft segment. The structural behavioral characterization of these polymers was performed through FTIR spectroscopy, thermogravimetric analysis, dynamic mechanical and thermal analysis, stress–strain measurements, and water contact angle measurements. The resulting linear polyurethane urea elastomers exhibit good mechanical properties with breaking strains of 300–890% and tensile strengths of 8–13.5 MPa. Thermogravimetric analysis indicated that the thermal degradation of poly(urethane urea) started at about 280–300 °C, higher than the degradation temperature of conventional polyurethane. The improvement of properties was influenced by the hard segment content and the nature of the crosslinker, but most of all by the structure and amount of the urea introduced through 2,4-diamino-6-phenyl-1,3,5-triazine into the polymer backbone chain.