基于VARI工艺的吸波复合材料制备与性能研究?

Prepararion and properties of VARI processed microwave absorbing composites

通过真空辅助树脂灌注工艺(VARI)制备了以羰基铁粉(CIPs)/玻璃纤维(GFs)/环氧树脂(EP)为吸波层、碳纤维(CFs)/EP为反射层的结构型吸波复合材料。通过考察工艺窗口温度、CIPs与EP质量比(m_(CIPs)/m_(EP))、搅拌时间和酒精含量{mC_2H_5OH/m(CIPs+EP)}4个因素对树脂体系黏度、可操作时间、凝胶时间的影响,采用L_9(3~4)正交试验对VARI制备以上复合材料的工艺条件进行优化,结果表明:最优VARI工艺条件为工艺窗口温度35℃、m_(CIPs)/m_(EP)为1.5:1、搅拌时间为30 min和酒精含量为5%。通过傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)和矢量网络分析仪(VNA)等现代分析技术对其化学组成、微观形貌、吸波性能进行了表征。结果表明:CIPs并未与EP形成新的结合键。CIPs颗粒呈球状,粒径为3～5μm,且CIPs颗粒均匀的分散于吸波层中,当m_(CIPs)/m_(EP)为2:1、厚度为2.5 mm的CIPs/GFs/CFs/EP复合板材在11.6 GHz处的反射损耗最大为-26.5 dB,反射损耗小于-10 dB的频宽可达3.6 GHz,具有良好的吸波性能。

A structural absorbing composite was prepared via vacuum assisted resin infusion (VARI) process, where carbonyl iron powder (CIPs)/glass fiber(GFs)/epoxy(EP) were used as the absorption layer and carbon fibers(CFs)/EP as the reflection layer. Effects of process temperature, mass ratio of CIPs and EP, stirring time and alcohol concentration on epoxy viscosity, operation time and gelling time were investigated. Process conditions were optimized by L9(34) orthogonal design. The optimum conditions are: process temperature = 35 ℃, mCIPs / mEP = 1.5:1, stirring time = 30 min and alcohol concentration = 5%. FT-IR, SEM and vector network analyzer (VAN) were used to investigate chemical composition, micro-morphology and microwave absorbing properties of the composite. The results show that CIPs and EP do not form new bonds. CIPs are typical spherical shape evenly dispersed in the absorbing layer with diameter of 3~5 μm. When mCIPs / mEP is 2:1 and thickness is 2.5 mm, the absorption bandwidth with reflection loss value <-10 dB is up to 3.6 GHz and the maximum microwave decay value is -26.5 dB at 11.6 GHz. The CIPs/GFs/CFs/EP composite exhibits excellent microwave absorbing capacity.