Abstract:

MDI-50 type polyurethane elastomer was prepared from a prepolymer system based on MDI-50，polyol and MOCA chain extender. The effects of mass fraction of —NCO in prepolymer on properties of the elastomer were studied. The structure and performance were analyzed by means of DSC，TG，FTIR and mechanical properties test. The results showed that hardness and glass transition temperature of MDI-50 type polyurethane elastomer increased with increasing molar ratio of NCO/OH in prepolymer reactive system. The tearing strength and tensile intensity increased at first and then declined with increasing mass content of —NCO. However，elongation at break of the elastomer and viscosity of prepolymer decreased with increasing —NCO mass content. It showed that better properties were obtained at 2.22 of the molar ratios of NCO/OH. —NCO mass content had little influence on thermal stability of the elastomer .The result provided data for the application of formula design of MDI-50 type polyurethane elastomer.