Study On Modification Of Resin By Polyimide Powder

Epoxy resin has many advantages and is widely used.In order to make the epoxy resin to be able to play a role in more stringent application fields and working environment,improve its temperature resistance,wear resistance and impact strength is the top priority.Polyether imide resin has excellent comprehensive properties,but its wear resistance is slightly poor and its thermal expansion coefficient is high.Polyimide(PI)has excellent properties and is often made into fibers,films and plastics.Using the method of mechanical grinding PI fiber to recover PI products and waste materials to prepare rod PI powder can not only reduce the cost,but also use PI powder as filler to improve the tribological properties,impact resistance and heat resistance of the resin.The specific research contents are as follows.After alkali etching,the imide ring of PI rod-shaped powder was successfully opened to expose the amide bond and carboxyl group,which improved the surface activity and formed good interface.After plasma treatment with different surfactants A and B,the contact Angle of powder decreases,the surface activity is higher,and the activity of A is higher than that of B.The preparation process of epoxy resin reinforced by PI was determined.PI powder had a thickening effect on epoxy resin.The higher the content of PI,the higher the viscosity of the system.When the content of PI is 30w%,the viscosity of the system is moderate,and the powder dispersion of PI powder modified epoxy resin(PPMER-30)is uniform.Compared with pure epoxy resin system,the glass transition temperature of PPMER-30 increased by 11.08%,and the thermal decomposition temperature of 5%and 10%increased by 8.06%and 11.29%,respectively.When the air atmosphere is 110℃ for a long time in 12h,the temperature resistance increases greatly.The increase of PI powder content will lead to the decrease of thermal expansion coefficient,and the thermal expansion coefficient of PPMER-30 system is 8.92%lower than that of pure epoxy resin.The higher the content of PI powder,the lower the tensile strength.When the content of PI is less than 30w%,the higher the content of PI powder,the higher the impact strength.Compared with the pure epoxy resin system,the impact strength of PPMER-30-A system with 30w%A plasma treated powder increased by 47.19%.In addition,the friction coefficient of PPMER-30-A system is reduced by 25.67%,and the wear volume is smaller than that of pure epoxy resin after wear treatment.The crosslinking system model of epoxy resin and PI molecular chain was established.With the increase of the degree of ring opening,the free volume fraction and the coefficient of thermal expansion of the model decrease.Compared with the closed loop system,the fully open loop system has higher relative bond energy,more hydrogen bonds and stronger interface.The preparation process conditions of PI powder modified ULTEM 1000R resin were investigated.By applying the maximum temperature of 260℃ and pressing 3MPa to hold the resin for 30min,each system of PI powder modified ULTEM 1000R resin was prepared.The introduction of PI powder has the effect of thickening ULTEM 1000R resin.The higher the content of PI,the higher the viscosity of the system.By changing the content of PI and adjusting the viscosity,the system samples with good morphology of 0,10w%,20w%and 30w%PI were obtained.The glass transition temperature of the 10w%system is 222.17℃,and the glass transition temperature of the 10w%system is 5℃ higher than that of pure ULTEM 1000R resin.The temperature of thermal decomposition does not change much.The temperature resistance of pure ULTEM 1000R resin decreased from 0.12%to 0.05%when PI was added 30w%at 200℃ for 12h.The thermal expansion coefficient of ULTEM 1000R resin modified by PI powder decreased greatly,and the value of pure ULTEM 1000R resin decreased from 48.36ppm/K to 38.28ppm/K after adding 30w%PI powder.The tensile strength and impact strength of PI powder modified ULTEM 1000R resin decreased with the increase of PI content.The introduction of PI powder has little effect on the friction coefficient of the resin,but the wear volume is reduced and the wear resistance is enhanced.