Preparation And Penetration Properties Of Modified Polystyrene/UHMWPE Fiber Composites

Ultra-high molecular weight polyethylene fiber(UHMWPE)reinforced composites with high specific absorption energy,good anti-ballistic impact performance,is used in the military and for personal protection.Nevertheless,due to the flat surface and absence of polar groups on the main chain,it is difficult for the UHMWPE fiber to combination with general resin through chemical bonds,resulting in poor surface adhesion.Therefore,it is normally used by compositing with the modified resin matrix.Polystyrene(PS)is a common weak polarity thermoplastic resin,with advantages of good processing performance,excellent infiltration with UHMWPE fiber,but with disadvantages of poor heat resistance and brittle.Relatively,ethylene-vinyl acetate copolymer(EVA)showed characteristic properties namely high flexibility,elasticity,and filler compatibility.Therefore,in this article we selected UHMWPE fiber as a reinforced fiber of bullet-proof composite.The modified PS/UHMWPE fiber bulletproof composites were synthesized by using EVA modified PS resin as the resin matrix of the composites,(AIBN)as initiator,triallyl isocyanurate(TAIC)as crosslinking agent,with a hand-assisted and vacuum-assisted molding process.The mechanical and thermal properties of modified resins and composites were analyzed.Through the trajectory penetration experiment to investigate its penetration performance,and using ANSYS finite element analysis software to simulate the penetration process of composite materials,it can be resulted in the experimental basis and theoretical analysis for the preparation of resin-based fiber reinforced elastomer composite materials and the corresponding performance of ballistic resistanceThe main research contents and conclusions are as follows:(1)Under a temperature of 50?±2?,the resin viscosity with EVA quality fraction was less than 35% can meet the technical requirements.The tensile strength of the modified resin and the composites enhanced with the increasing quality fraction of EVA.When the EVA content was 35%,the tensile strength of the modified resin was 72.7MPa and the elongation at break was 1201.3%.Corresponding,the tensile strength of the composites was 190.7MPa and the tensile modulus was 941.1MPa.The resin and composite showed the optimal mechanical properties when the addition amount of TAIC was 2%.And the corresponding tensile strength of the modified resin was 62.6MPa and the elongation at break was 1251.28%.The tensile strength of the composites was 169.3MPa,the tensile modulus was 1003.3MPa,and the peel strength is was 13.2N/5mm.(2)Through the dynamic thermodynamics analysis of the composites,the composites with more styrene exhibited a higher storage modulus,better wettability between the resin and fiber,an increasing interfacial bonding force and higher stress transfer between the fiber and the resin interface.In addition,the addition of the crosslinking agent TAIC enhanced the elasticity of the resin and improved the storage modulus of the composite material.(3)Through the experimental results of ballistic penetration,it can be conclued that the initial and residual velocity of the bullet were nonlinearly increasing and the thicker target displayed an improved ballistic performance.The composite material was observed to be damaged by the projectile,and the fibers and the resin on the contact surface of the bullet were compressed and deformed.The exit surface was raised and the shear deformation occurs in the vertical direction.(4)The ANSYS finite element simulation of the composite material is was carried out.By studying the dynamic response of the bullet during the penetration process,it was observed that the minimum velocity of the bullet was 341m/s when bullets penetrated the target at the speed of 500m/s,and finally stabilized at 394m/s,decreased by 34.3%.According to the study of damage from the target penetrate,it can be seen that in the bullet penetration point,the material received the effect of extrusion,and large stress.The stress on the projectile area contacting with the bullets was also great,leading to fiber deformation and base destroyed,which was consistent with the experimental situation.