Study On Preparation And Properties Of Rigid Polyurethane Porous Materials

Polyurethane porous material is a kind of polymer foam material.Because of its many kinds of foam,it is widely used in modern society.Polyurethane foam is mainly composed of soft foam and rigid foam.Soft foams are mainly porous structures,and hard foams are mostly closed cell foam.The application of rigid foam materials in China is relatively narrow.Therefore,it is of great significance to solve the problem of hard bubble opening,broaden the application field and break the monopoly of foreign technology.The inner pores of rigid polyurethane foam can be changed with the change of raw materials or environment.The bubble structure inside the foam not only affects the size and opening of the foams.It will also change the properties of foam materials.In this paper,rigid polyurethane porous materials were synthesized,The effects of soft segment and hard segment,foaming agent and filler system on the mechanical properties,cellular structure and heat resistance of rigid polyurethane porous materials were investigated,The foaming formula most suitable for this material is composed.The experimental results are as follows:（1）Polycaprolactone（PCL）rigid polyurethane porous material has better comprehensive mechanical properties,higher compression and bending strength,good temperature resistance.The bubbles in the material are uniform,small aperture coefficient.The cell wall is thin,but the brittleness is high and the reaction speed of the system is fast;When the relative molecular weight of PCL polyols increased,the mechanical properties of PCL polyols first increased and then decreased,but the toughness will be improved and the bending strength will be increased.The reaction speed of the foam system is low,and the structural parameters of the foams increase with the increase of relative molecular weight.Use the PCL210N and PCL220N combination system,when the ratio is 70/30,the synthesized foam material has the best comprehensive performance.（2）Compared with different kinds of chain extender,the compressive strength and bending strength of rigid polyurethane porous materials obtained by chain extender h are higher.The bubble is close to the sphere,with small pore shape coefficient and the best comprehensive performance.After the use of crosslinking agent,the glass transition temperature of the material increased obviously.When using tea as crosslinking agent,the hardness and mechanical strength of the material are the highest.The pore size is larger,the foams are thinner,and the anisotropy of foams is lower.The glass transition temperature is higher and the temperature resistance is better.When the dosage of TEA is 2%,the mechanical strength of foams is the highest.The pore shape coefficient is close to 1,the distribution of bubbles is the most uniform,the pore wall is thinner,and the glass transition temperature is higher.When the hard segment content is 72%,the bending strength is the highest and the pore diameter is larger.With the increase of hard segment content,the glass transition temperature and the heat resistance of the material increase.But if the proportion of hard segment is too large,the mechanical properties will decline.（3）Comparing different foam stabilizers,the mechanical strength of B8485 foam is the highest.The pore size is uniform,the structure is relatively complete,and the pore shape coefficient is close to 1.The mechanical strength of the foamed material with NiaxL-6164 is higher,and the foams are more uniform and the pore size is smaller.The shape is close to the sphere,and the effect of opening is the best.With the increase of HCFC-141b ratio,the pore diameter of the cell gradually increased,the mechanical properties increase first and then decrease.When H₂O/HCFC-141b=9.5/0.5,the material has the highest mechanical strength,the most uniform bubble size distribution,the pore shape coefficient is close to 1,the thermal conductivity is low,and the temperature resistance is good.（4）Compared with different stearates,the melting point of zinc stearate is lower.In the polyol component,the dispersing effect is good,the distribution of bubbles is the most uniform,the opening effect is the best,the conductivity of the material is high,and it is greatly affected by the temperature.With the increase of the content of zinc stearate,the mechanical strength of the material showed a trend of increasing and decreasing.When the content is 0.5%,the material has the highest mechanical strength and the clearest bubble,the structure is the best,and it will continue to increase,the cell structure will become worse,and the temperature resistance will decrease.The faster the stirring speed of the filler in the polyol component,the more uniform the zinc stearate dispersed in the foam.The better the bubble structure is,the higher the hardness and mechanical strength of the material are.