Synthesis And Properties Of Polyether Polyurethane-imide Material

Polyether polyurethane materials have many advantages such as high elasticity,low temperature resistance,fatigue resistance,water resistance,etc.,but their mechanical strength is low and their high temperature resistance is poor.Polyimide has excellent oil resistance,radiation resistance,high strength,good chemical resistance and good dielectric properties,but polyimide is difficult to be dissolved and melted at the same time it's flexibility is poor.Due to it's high costs,it is difficult to be applied in many areas.If polyimide was introduced into polyurethane,the product will combine the advantages both of them.We separately synthesized polyurethane-imide foams,elastomers and adhesives,and discussed the factors affecting their reaction process and properties.The main research contents are as follows:1.We have synthesized polyimide powder,which has excellent heat resistance and high glass transition temperature.It is suitable for PI when DMAC as the solvent.Polyurethane-imide foam with TDI was synthesized.The results showed that water content had a great influence on the cell size of the foam and had little effect on the molecular structure of the foam,so the Tg and heat resistance did not change significantly.Comparing the properties of PUI foam and PU foam,it can be found that PUI foam has higher mechanical strength and better heat resistance.2.The polyurethane-imide elastomer was successfully synthesized by prepolymer method.It is found that 75 ° C is a suitable temperature for the prepolymerization reaction,and the imidization temperature is preferably at 110?.When MDI:PTMG1000:PMDA = 2.5:1:1.5,the elastomer has better mechanical properties.As the content of the hard segment in the PUI increases,the heat resistance increases,the Tg increases,the dynamic heat loss decreases,and the chemical solvent resistance becomes better.The molecular weight smaller,the heat resistance better,the phase separation more obvious,the Tg higher;the PUI with PTMG has better heat resistance,lower heat loss than the PUI with PPG,their Tg have little difference.Compared with PU,PUI has better chemical resistance,heat resistance and higher mechanical strength.Compared with PI,PUI has low elongation at break and better flexibility.PUI leather samples were successfully prepared using the polyurethane-imide solution.3.We synthesized PUI-EP adhesive,considering its mechanical strength,brittleness,bonding performance and heat resistance,we believe that when NCO% = 2%,hardener is MOCA,PMDA content is 6%,the comprehensive performance is better.