| Polyurethane elastomer having superior comprehensive performance are widely used in various fields of industrial production. Polyurethane elastomer could have more heat under the dynamic condition and its high temperature resistant performance is poor, which limits the application of the polyurethane elastomer in some harsh conditions. It is great significance to improve the dynamic and thermal performance. The microcelluar polyurethane elastomer have been used more and more widely especially in the high speed railway because of its light quality, sound absorption and noise reduction, high mechanical strength. Therefore, it is very prospect to study the preparation of more excellent performance of microcelluar polyurethane elastomer.In this paper, first of all, we studied the effect of the structure of soft segment, kind of chain extender and isocryanate, hard segment content and aramid short fiber on the propertites of polyurethane elastomer by using prepolymer method to prepare the material based on MDI. We also studied the effect of the dosage of foaming agent, structure of polyols, the kind of chain extender and the ratio of MDI/100 LL on the propertites of microcelluar polyurethane elastomer. We founded that:(1)Polyurethane elastomer based on polyester type had high retention of tensile strength on high temperature and the heat resistance was better, but more heat under the dynamic condition was made.Compared to Polyester-PUE, the tan? of Polyether-PUE was lower, but the heat resisitance was poor. With the increase of molecular weight of the polyester, mechanical strength and heat resistant decrease, but its dynamic performance were improved. Selection the system of PCL220N/PTMG2000,its overall performance was better.(2) Selection of single chain system, the overall performance of the BDO obtained excellent overall performance; and selected BDO/TMP chain system,the elastomer had good mechanical strength and compression permanent deformation was small. The retention rate of material high temperature strength was relatively high and friction was lower; Increasing the content of hard segment will help to improve the mechanical strength and heat-resistant properties of the material; The system of MDI, adding a certain amount of NDI will help to improve the overall performance of materials. When the amount of 40 parts, the mechanical properties, heat resistance and dynamic properties of the material were more better.(3)Polyurethane elastomer with aramid short fiber, adopting the method of prepolymer, had better mechanical properties, heat resistance and dynamic performance; the length to diameter ratio of different aramid fiber had a certain influence on the performance of polyurethane elastomer; the material contained aramid short fiber which was1 1670dtex/3mm that had excellent properties; with the increase content of aramid short fiber, mechanics performance of the material first improved and then reduced; when the amount was 0.5%, the damping factor of material was the lowest.(4) With the increase content of foaming agent, mechanical properties and heat resistance of the material decreases, static stiffness decreased and the static and dynamic stiffness ratio was lower at 0.13%. With increased content of PTMG1000, the mechanical strength of the material, static stiffness and the heat resistance were improved. When the ratio of PTMG2000/PTMG1000 is 40/60, the overall performance of the material is relatively excellent. We select the chain system of EG/TMP was 2/1, the cell structure of the material is relatively uniform, and static and dynamic stiffness of the material was lower,at the same time, high temperature performance was good, and compression set were more smaller than used alone EG. Based on the above experiments, when choose the the ratio of MDI/100 LL is 70/30 to prepare microcellular polyurethane elastomer, its mechanical strength was high, uniform cell, static and dynamic stiffness is relatively low, and high and low temperature performance is relatively excellent. |
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