Direct Writing 3D Printing Of Continuous Carbon Fiber/polyimide Honeycomb Structure And Its Performance Researc

In recent years,with the rapid development of aerospace industry,the requirements of flight device materials were increasing for lightweight,high temperature resistance and mechanical properties.The 3D printing of lightweight structural composite materials also began to attract great attention in the scientific research community.At present,although traditional polylactic acid,polycarbonate,nylon and other composite materials had good mechanical properties,which the temperature resistance grade of these resins was less than 200℃so that they can’t meet the high temperature resistance requirements of new aerospace structural parts.Meanwhile as for polyether ether ketone,polyether ketone.Although they had the characteristics of high temperature resistance grade,its processing temperature requirements were too harsh so that the processing process was prone to problems such as wire drawing.The phenomenon seriously affected the processing accuracy.In this context,we looked for another thermo-resistant resin polyimide as the matrix and used the direct writing 3D printing combined with thermal-imidization"secondary reaction"to prepare CF/PI honeycomb structure,which gave it the characteristics of light weight,high strength and high temperature resistance.Based on the requirement of 3D direct writing printing technology.The printing ink must have certain properties of storage and shear thinning.The paper started from the synthesis of self-healing polyamide brine gel and studied its thermal-imidization process.Finally,we successfully prepared CF/PI honeycomb structure by adjusting printing program and analyzing its comprehensive properties.The results showed that density of the printing cell structure can be flexibly adjusted by adjusting the length of the print topology unit(Its density can range from 0.195 g/cm~3-0.335 g/cm~3).meanwhile the square honeycomb structure had excellent volumetric compressive strength(up to 50.20 MPa),which was much higher than that of CF/PLA honeycomb and CF/PEEK negative Poisson’s ratio honeycomb that reported in the other literature.The shear tests showed that the shear strength of vergence direction was greater than that shear strength of the forward direction.There were obvious differences in shear failure modes.And the long-term use temperature of the honeycomb was 350℃.So It can be seen that CF/PI honeycomb prepared by 3D printing in our laboratory was expected to be applied in automotive,aerospace and other fields,such as aero-engine,satellite solar array substrate,cabin body,etc.