Research On Mechanical And Waveabsorbing Properties Of Modified Carbon Fiber/Silicone Rubber Flexible Composite

With the rapid development of science and technology today,a new generation of information revolution represented by 5G is coming.While bringing unprecedented life experience,the accompanying complex electromagnetic environment also has a serious negative impact on human health and information security.In the military field,as the armed forces of various countries continue to deepen their mechanization and informatization,the survivability of modern weapons and equipment is facing severe challenges,and the importance of stealth capabilities has become increasingly prominent.On the other hand,as the performance of new equipment is greatly optimized,the service environment of wave-absorbing materials has become more severe,and the integrated structure/absorbing materials have brighter application prospects.In this study,firstly,a comprehensive and detailed study of the performance degradation of carbon fiber-carbon nanotube multi-scale reinforcements(CFs/CNTs)prepared by chemical vapor deposition(CVD)was carried out.The reason for the performance degradation was that the carbon fiber was corroded by the catalyst nickel.The mechanism and process of this corrosion phenomenon is clarified in detail.Later,this principle was applied to develop a new type of carbon fiber-based flexible structure/wave absorbing integrated material.The specific method is based on this principle,using chopped carbon fiber as a raw material,using a similar process to directly corrode the carbon fiber,and a modified carbon fiber with a porous structure and a carbon product with a regular graphite crystal structure distributed on the surface is obtained.It is made into a composite material with HTV silicone rubber with good flexibility,heat resistance and corrosion resistance,and finally a modified carbon fiber reinforced silicone rubber-based composite material with excellent wave absorbing ability and certain mechanical reinforcement is obtained.The main research scopes are as follows:(1)The corrosion of the fiber by the catalyst is the most important factor leading to the performance degradation.The mechanism: the nickel attached to the fibers is catalyzed by Kirkendall effect and high temperature,dissolving the carbon fibers,forming pores,and generating carbon by-products.The other end of the by-products is connected to a nickel ball embedded in the fiber,which also constitutes a hair-like structure;(2)As the corrosion temperature increases,the microwave absorbing and mechanical properties of the composite material will increase first and then decrease at the same time.The material at 700 ? has both the best absorbing and mechanical properties.As the catalyst concentration increases,the material's microwave absorbing performance and mechanical properties also show a trend of first increasing and then decreasing,but the optimal mechanical properties and absorbing properties no longer appear at the same sample.When the catalyst concentration reaches 5 wt.%,a carbon product with a regular carbon lattice,which is mainly graphene and carbon nanofibers,grows on the surface of the fiber.At this time,the material can maintain a certain mechanical enhancement while achieving excellent microwave absorption performance.The highest reflection loss can reach-25 d B,and EAB(10)can reach 3.357 GHz.When the content of the modified fibers with this performance in the composite material reaches 4 wt.%,its absorbing performance can reach-44.74 d B;(3)The use of specially arranged magnetic metal arrays for composite materials can achieve ideal,convenient,fine-tunable,and high-performance wave-absorbing performance control.The absorbing performance of the device can be easily adjusted by changing the regular array of iron nails inserted on the surface to achieve the effect of nearly real-time regulation of the absorbing performance.While maintaining strong absorbing ability of-20 d B(99 %)or more,the wave-absorbing frequency is gradually shifted from the XC band to the low frequency to C Band;(4)After undergoing direct damage from various experiments such as metal array control,rigid splint control,heat resistance and corrosion resistance,the composite material still retains excellent absorbing properties,indicating that the composite material prepared in this study possess excellent weather resistance performance and durability.It turns out that the modified carbon fibers prepared by this principle possess excellent microwave-absorbing performance and certain mechanical enhancement effect at the same time with a low filling amount,while maintaining weather resistance and durability and it is an ideal mechanics/wave-absorbing performance integrated material.