Study On Factors Affecting The Dynamic Performance Of Microporous Polyurethane

Microcellular polyurethane elastomer(referred to as microcellular PUE)is a special polyurethane material.Because of the cellular structure,its density is between the elastomer and the soft foam.It has the advantages of low density,impact resistance,high resilience,etc.Performance,can be used as shock-absorbing materials and energy-absorbing materials.At present,there are relatively few studies on low-density microcellular polyurethane elastomers.In order to better broaden the application of microcellular polyurethane elastomers,it is necessary to study the factors that affect its dynamic properties.In this paper,low density microporous polyurethane elastomers are synthesized by means of whole-water foaming and semi-pre-polymer method,and the effects of the types of polyols,polyol molecular weight,polyether-type polyols,pre-polymer NCO% content,R values,chain-expanding cross-linking agents,chain-expanding agents,foam stabilizers,foam stabilizers,water dosages and other factors are explored.The main findings of the study are as follows:(1)Polyester-based materials have higher tensile strength and elongation at break,and polyether-based materials have good falling ball resilience.The glass transition temperature and the ratio of dynamic and static stiffness of the microporous polyurethane elastomer are in the order of PTMEG2000 type <PPG220type <PEA20 type <PCL2000 type.Among the polyoxytetramethylene ether glycols of different molecular weights,PTMEG2000 type materials have better mechanical properties,low temperature properties and dynamic properties.PTMEG1000 type materials have the smallest ratio of dynamic and static stiffness.As the molecular weight increases,the dynamic properties of the material become worse.As the proportion of polyether polyol P36-28 increases,the mechanical properties of the material become better,the glass transition temperature of the material gradually rises,and the loss factor gradually decreases.(2)The increase of the prepolymer NCO% content causes the material density to decrease,the loss factor decreases,and various physical and mechanical properties and dynamic properties become worse.When the prepolymer NCO% content is 12%,the dynamic and static stiffness ratio of the material is the lowest.The increase of the R value increases the tensile strength of the material,the glass transition temperature increases,and the dynamic performance becomes better.At the same time,the falling ball resilience of the material becomes worse,and the dynamic and static stiffness ratio gradually decreases.(3)When BDO is used as a chain extender,the material has good mechanical properties,and the glass transition temperature of the material is the lowest.As the amount of BDO increases,the tensile strength and hardness of the material increase,and the glass transition temperature gradually increases.Low-temperature flexibility deteriorates,and dynamic performance of the material also deteriorates.When the amount of BDO is 7 parts,the dynamic and static stiffness ratio of the material is the smallest;when TEOA is used as a chain-extending cross-linking agent,the tensile strength of the material is the largest,and the glass transition temperature is the highest;when DEOA is used as a chain-extending cross-linking agent,the loss factor of the material is the smallest;When KC is used as a chain-extending crosslinking agent,the temperature corresponding to the loss factor peak of the material is higher.(4)When the amount of foam stabilizer increases,the cell size and cell structure of the material are more uniform.When the amount of foam stabilizer is 5 parts,the physical and mechanical properties of the material reach the best.When the amount of foam stabilizer exceeds 3 parts,the dynamic and static stiffness ratio of the material reaches the best.The materials synthesized by DC-193 and M-6688 foam stabilizers have better physical and mechanical properties and more closed-cell structures The L-580 material has the smallest dynamic and static stiffness ratio,and the M-6698 material has the largest dynamic and static stiffness ratio.With the increase in the amount of water,the number of cells in the material increases,the physical and mechanical properties of the material become worse,the dynamic performance becomes better,and the temperature range corresponding to the loss peak decreases;when the amount of water is 0.7 parts,the dynamic and static stiffness of the material Than the biggest.