| Microcellular polyurethane elastomer（MPUE）is a kind of material of which the performance and density between polyurethane elastomer and polyurethane foam.It has a lot of foam hole whose diameter from 0.1 um to hundreds of micrometers.At the same time MPUE has light qualitative,good resistance to impact and energy absorption,good load performance and high strength,good abrasion resistance.especially in shock absorption area.MPUE performs excellently,which can absorb75%95%shock energy.Thus,it is widely used in urban mass transit,construction engineering and other fields.In this paper,we studied the effect of kind of chain extender,the dosage of chain extender,the kind of isocryanate,NCO content,the structure of soft segment,the kind of foaming agent and the dosage of foaming agent on the propertites of microcellular polyurethane elastomer by using one-step method to prepare the material.We also studied the effect of flame retardant polyol and different kinds of foaming agents on flame retardant properties of MPUE.We founded that:（1）The properites of MPUE was better than others when the chain extender was ethylene glycol.With the increased of the dosage of chain extender,the main mechanical properties of microcellular polyurethane elastomer increased,but the elongation at break decreased.The ratio of dynamic and static stiffness of MPUE was minimum when the dosage of chain extender was 3phr.Compared to other isocyanate,MPUE synthesised by MDI performed excellently.PM-200 could also have effect on MPUE,the tanδand the ratio of dynamic and static stiffness was small when the amount of PM-200 was 5phr.With the increase of NCO content,the ratio of dynamic and static stiffness increased gradually.（2）Microcellular polyurethane elastomer based on PTMG had better comprehensive mechanical properties,smaller loss factor and the ratio of dynamic and static stiffness.When 330N/POP-36/28 was 50/50,the comprehensive performance of microcellular polyurethane elastomer was excellent.With the increase of molecular weight of soft segment,the mechanical properties of microcellular polyurethane elastomer,loss factor and the ratio of dynamic and static stiffness decreased.（3）We choosed H2O as foaming agent,CH2Cl2 as auxiliary blowing agent.With the increase of the ratio of CH2Cl2,the foaming time and curing time of MPUE increased gradually,the density decreased first and then increased,part of the obturator became a opening structure.We also found that loss factor and the ratio of dynamic and static stiffness increased first and then decreased when the ratio of CH2Cl2 increased gradually.However,compared with the performance of the water foam agent,CH2Cl2 reduced the dynamic performance of microcellular polyurethane elastomer.With the increase of dosage of foaming agent,the number of foam increased and appeared bubble phenomenon,mechanical properties decreased and the ratio of dynamic and static stiffness increase gradually.（4）Flame retardant polyols was not only improved the mechanical properties of microcellular polyurethane elastomer,also improved its heat resistance and LOI.Different kinds of flame retardants could reduce the mechanical properties of microcellular polyurethane elastomer,but in terms of the heat resistant,the expanded graphite and microcellular polyurethane elastomer compound perform excellently.Then we added melamine（MEL）and expanded graphite（EG）into MPUE,the LOI was the highest when MEL/EG was 1/1.With the dosage of ethyl diethyl phosphate（DEEP）added into MPUE increasing,the foam wall became thin,opening structure increased,the LOI of MPUE increased first and then decreased.we got the highest LOI of MPUE when the DEEP dosage was 7phr and the highest LOI was 32.7%. |
