Research On Surface Copper Plating Of Flax Fiber

Plant fiber have lots of advantages, such as light weight and high strength,green and eco-friendly, moisture absorption and thermal insulation. Plant fiber reinforced polymer composites materials are widely used in building materials,automobile, basic construction and other fields in recent years. The research of surface metallization of flax fiber is based on keeping the excellent properties of the fiber,and give the fiber good conductive properties and antibacterial properties,enlarging the application scope of flax fiber. This article studied the influence of temperature, p H value, the concentration of CuSO4, EDTA·2Na and HCHO on the chemical copper plating layer. By experimental results, the p H value affected the copper layer most significantly. Through the Taguchi model, it could be concluded that the optimal technological parameters for chemical copper plating of flax fiber are as follows: Cu SO4 0.28 mol/L, HCHO 1.5 mol/L, EDTA·2Na 0.16 mol/L,temperature of 55 °C and the p H value of 13.0. Under the optimal parameters combination, the metal deposition rate of the copper plated flax fiber was122.5 μm/h, while the area resistivity could reach 0.082 Ω/cm2. The thickness of copper layer was 0.7 μm-2.1 μm. The copper layer on the flax fiber was uniform and compact with metallic lustre.The FTIR results showed that the functional groups on the surface of flax fiber didn’t have obviously changes both before and after activation process,which indicated that the activated process was not a chemical reaction but a physical adsorption process. By XPS and EDS testing results, the chemical composition of the plated layer on the flax fiber was copper, which was consistent with the reduction mechanism of formaldehyde. XRD analysis result showed that the copper in the coating was of cubic crystal structure.Combine the copper plated flax fabric and epoxy resin to prepare the flax fiber reinforced epoxy composites. The tensile test results suggested the tensile strength increased by 4.23%, because of the enhancement of mechanical interlocking between resin and fibers. While the modulus decreased by 6.78%caused by the degradation in acid and alkaline, the extension performance was improved obviously by 31.78% because of the exist of copper layer. By the DMA test results, the glass transition temperature, storage modulus, loss factor of copper plated composite plates was increased compared with unprocessed flax fiber composites which iwas resulted by the increase of inter-facial adhesion between flax fibers and epoxy. The antimicrobial properties test indicated that the copper coated flax fiber composite material had excellent antibacterial properties. Thecopper ions went through the cytomembrane of germ and combined with the enzyme to prevent the multiply of bacteria.From the results above, it can be concluded that the electroless plated copper layer on flax fiber surface was uniform and compact, with good electrical conductivity, inter-facial adhesion and antibacterial properties. The mechanical properties and thermal properties of copper plated flax fiber reinforced epoxy composites were better than the unprocessed ones. This study was prepared for the functional utilization of flax fibers.