Study On The Preparation Of Graphene Oxide And/or Carbon Nanotube Coated By Poly- Aniline Nanorod And Their Electromagnetic Interference Shielding Properties

With the development of technology, electromagnetic pollution has brought more and more harmness to the human’s life, and the electromagnetic interference (EMI) shielding materials are used to reduce it. Among them, the conductive polymer composites (CPCs), prepared by mixing conductive fillers with polymer matrixes, have broad application in the EMI shielding field. Carbon-based materials can act as promising CPCs fillers for their special structure and excellent physical and chemical properties. In the carbon-based materials, graphene and carbon nanotubes (CNTs) are the most attractive owing to their high aspect ratio, high mechanical strength and versatility. Polyaniline (PANI) is the most versatile conducting polymers for its controllable morphology, adjustable conductivity, anti-corrosion, light weight and environmentally friendly. In this thesis, the nanocomposites of CNTs and/or graphene oxide (GO) coated by aligned polyaniline nanorods were prepared (GO/PANI and GO/PANI/CNTs), and their application in EMI shielding were also investigated.(1) The nanocomposite with high conductivity and aspect ratio of GO/PANI nanocomposites were prepared by the dilute in situ polymerization.By discussing, the repulsive force from the static and the agglomeration caused by the interfacial tension were discovered to influence the morphology of GO/PANI, and got the optimum polymerization conditions. Its conductivity and EMI shielding effectiveness (EMI SE) were tested by mixing it with paraffin matrix at different weight percentage. Through analysis, we found that their variation trend were quite different at different contents. The increase range in the medium content (30-50 wt%) was much larger than at higher (≥ 50 wt%)or lower (≤ 30 wt%) mass ratios, which could be explained reasonably by the dipole polarization, interfacial polarization and electros hopping (conductivity).(2) The nanocomposites of GO/PANI/CNTs were synthesized by changing the weight ratio of GO, CNTs and aniline in the reacting solution, and got the optimum polymerization conditions. Their structure and thermal stability were analysized by FT-TR, UV-vis, XRD and TGA measurements. Its conductivity and EMI SE were also tested by mixing it with paraffin matrix at different weight percentage. Through comparison, its trend was similar with the GO/PANI nanocomposite. At the same contents, the conductivity and EMI SE of GO/PANI/CNTs composite were higher than that of GO/PANI nanocomposite, which could be attributed to the effective networks and EM wave absorption achieved by the CNTs.(3) The different weight percentage of GO/PANI nanocomposite were mixed with the waterborne polyurethane (WPU) and thermoplastic polyurethane (TPU) matrixes, and coated the solutions in the watch glasses or on the surface of glass slides to make the corresponding membranes. Its dispersity was characterized by the optical microscope, SEM and TEM measurements, and found that the hydrophobicity GO/PANI nanocomposite could be dispersed better in the TPU matrix rather than the WPU matrix. We also mixed the GO/PANI/CNTs with the TPU matrix by the same method, which proved that the TPU was the good matrix for dispersing the hydrophobicity fillers (GO/PANI and GO/PANI/CNTs). Their thermal stability was studied by the TGA and DSC measurements, and discovered that the degree of hard segment’crystallinity could be enhanced by incorporating the fillers of GO/PANI or GO/PANI/CNTs composites. Besides, the conductivity and EMI SE of fillers/TPU were higher than the fillers/paraffin at the same content. The obtained composites have promising application in the EMI shielding field.