Preparation And Ballistic Perfoamance Of Polyimide Fiber Reinforced Thermoplastic Resin Matrix Composites

With the technological advances and development in the military field,the penetration and lethality of various weapons and bullets are also increasing,which also puts forward higher and higher requirements for the protective performance of ballistic protective equipment.High-performance organic synthetic fiber plays a leading role in the field of individual protection because of its low density and high specific strength.As a new type of high-performance organic fiber,polyimide（PI）fiber not only has excellent mechanical properties,but also has the outstanding comprehensive properties of PI material,which makes it show a good application prospect in the field of individual ballistic protection.In this paper,a series of fiber reinforced thermoplastic resin matrix composite target plates were prepared by hot molding with PI fiber and ultra high molecular weight polyethylene（UHMWPE）fiber as reinforcements,and shooting test were carried out.The influences of reinforcement structure,penetrator type,interface peeling strength and hybrid structure on the ballistic performance of the composites were discussed,the damage mode and protection mechanism of the target are analyzed through the target morphology and nondestructive testing,in order to provide reference for the application of PI fiber material in the field of ballistic protection.The results show that:（1）For PI fiber reinforced thermoplastic resin matrix composite target,the target of UD structure has better protection effect of 7.62mm pistol bullet,and the target of fabric structure has better protection effect of 1.1g fragment;for the fabric reinforced target with the similar resin matrix,resin content and area density,the more number of fabric layers,the higher V₅₀value of the target.With the increase of interface peeling strength,the V₅₀and specific energy absorption（SEA）values of the target increased first and then decreased;Suitable interface peeling strength can play a better role in energy absorption and improve ballistic performance.（2）The modulus of the reinforcement fiber used on the front surface of the composite target has a great influence on the ballistic performance of the target.Taking PI fiber with higher modulus as the reinforcement in the front area of the target can bring better bulletproof effect.The high modulus in the front area of the target makes the transverse and longitudinal stress waves generated by the impact of the bullet can be transmitted quickly,so as to dissipate more energy,make delamination occur at a deeper depth of the target and expand to a wider area along the in-plane direction.（3）PI fiber and UHMWPE fiber have their own advantages in reducing the back face signature（BFS）and improving the SEA of the target,respectively.With the increase of the number of layers of UHMWPE fiber in the target,the SEA of each hybrid fiber reinforced target increases.Among the targets with different hybrid structures under the same hybrid ratio,the asymmetric laminated structure（H3）with UHMWPE fiber as front surface and the sandwich structure（H4）with PI fiber as front surface have lower BFS.H3 and H4 structure can make PI fiber and UHMWPE fiber give full play to the synergy,and take into account the requirements of individual ballistic protection field for the ballistic limit speed and BFS of composites.They are the ideal choice for the design and preparation of PI/UHMWPE hybrid fiber reinforced composites.